TO: HONORABLE CHAIR AND MEMBERS OF THE PLANNING
COMMISSION
FROM: Carl Stiehl, City Planner
PREPARED BY: Chris Tracy, AICP, Senior Planner
SUBJECT: title
Reintroduction of Hillside Ordinance Updates (DCA-2021-2396) to amend the Murrieta Development Code
end
RECOMMENDATION
recommendation
1. Find that the proposed action is consistent with the Public Resources Code Section 21000 et. Seq. (the California Environmental Quality Act (CEQA)) pursuant to Title 14, Division 6, Chapter 3 of the California Code of Regulations (CEQA Guidelines), Section 15162 for the reasons specified in this report; and
2. Adopt a Resolution (Attachment 1) recommending that the City Council introduce and place on first reading an Ordinance for the Title 16 updates reflective of Attachments 2 (Exhibit “A”) and 3 (Exhibit “B”) entitled:
A RESOLUTION OF THE PLANNING COMMISSION OF THE CITY OF MURRIETA, CALIFORNIA, RECOMMENDING THAT THE CITY COUNCIL AUTHORIZE THE FILING OF THE ENVIRONMENTAL DETERMINATION AND APPROVE DEVELOPMENT CODE AMENDMENT 2021-2396 RELATED TO CHAPTERS 16.08, 16.14, 16.18, 16.22, 16.24, AND 16.28.
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ENVIRONMENTAL
The proposed ordinance amendments have been reviewed for consistency with prior environmental documentation prepared and certified by the City of Murrieta, including the adopted Negative Declaration for implementation of the Comprehensive Development Code approved on October 28, 1997, as well as the Murrieta General Plan Final Program EIR (SCH No. 2010111084) and 2021 Subsequent SEIR. The evaluation was conducted pursuant to Public Resources Code section 21166 and CEQA Guidelines section 15162.
The City’s original 1994 General Plan, along with the subsequent implementation of the Comprehensive Development Code in 1998, established a longstanding policy framework recognizing hillside areas, ridgelines, open space, and rural character as important community resources warranting preservation and specialized development consideration. Since incorporation, the City’s General Plan and zoning regulations have consistently addressed hillside development constraints, environmental considerations, grading practices, visual resources, drainage, fire safety, and terrain-sensitive site design. The 1994 General Plan specifically identified preservation of significant landforms, protection of scenic hillsides and ridgelines, maintenance of rural character, and the use of specialized planning and design techniques for hillside areas as foundational community objectives which have been carried over through the years to the current General Plan adopted in 2020.
The proposed ordinance amendments do not establish fundamentally new land use policy, expand allowable development intensity, or introduce new categories of development within hillside areas. Rather, the amendments modernize, clarify, codify, and refine implementation mechanisms associated with existing hillside development policies and standards that have been embedded within the City’s regulatory framework for decades. The amendments accomplish the following:
• Clarify applicability of hillside standards through a codified GIS-based Hillside Overlay Map;
• Replace outdated and inconsistently applied average slope calculations with standardized GIS-based analysis;
• Establish more objective and internally consistent development standards;
• Clarify retaining wall, landscaping, grading, and building height methodologies;
• Improve administrative consistency and project predictability;
• Further implement longstanding General Plan policies concerning hillsides, ridgelines, and community character.
The amendments therefore represent a continuation and refinement of existing hillside preservation and development regulations previously evaluated in the City’s prior environmental documents, rather than a substantial change in land use policy or environmental impact potential. Staff further determined that the proposed updates would not result in new significant environmental impacts, substantially more severe impacts, substantial changes to the project, substantial changes in circumstances, or new information of substantial importance requiring preparation of a subsequent or supplemental environmental document pursuant to CEQA Guidelines section 15162. The previously certified environmental documents adequately address and cover the proposed modifications reflected in Attachments 4 and 5.
PRIOR ACTION/VOTE
On June 28th, 2023, the Planning Commission held a duly noticed public hearing on the proposed Development Code Amendment (DCA-2021-2396) as it relates to hillside development and recommended that the City Council adopt the proposed ordinance. (Vote: 4-0)
EXECUTIVE SUMMARY
Since 2022, the City staff has worked to modernize its hillside development regulations, which have remained largely unchanged for nearly three decades and were often criticized for being subjective and inconsistent. Recognizing that original standards were applied citywide without precise mapping, the City Council initiated a series of workshops between 2022 and 2026 to carefully review each aspect of the hillside regulations and overhaul the related sections of the Municipal Code and Development Code (Murrieta Municipal Code Title 16). The primary goal of these updates is to replace antiquated formulas and vague criteria with clear, objective standards. By utilizing modern Geographic Information Systems (GIS) technology, the City has established a formal Hillside Overlay Map, ensuring that restrictive regulations, such as a 25% slope threshold, apply only to designated areas rather than citywide, which was never the intention.
The proposed amendments introduce specific technical refinements to improve administrative efficiency and project predictability for both staff and applicants by accomplishing the following:
• Establishes clearer and more objective hillside development standards to improve administrative efficiency and project predictability for applicants and staff (see Sections 16.24.020, 16.24.040, and 16.24.050).
• Introduces a standardized methodology for measuring building height on sloped lots and replaces manual average slope calculations with GIS-based data (see Sections 16.18.080(A), 16.24.020(B), and related Figures 16.18-1 through 16.18-6).
• Clarifies retaining wall, landscaping, and fuel modification zone requirements to improve consistency and support fire safety objectives (see Sections 16.24.060(E), 16.24.060(F), and 16.24.060(I)).
• Incorporates enhanced hillside design guidelines, including muted color palettes, contour grading, tiered retaining walls, and integrated landscaping, to reduce visual impacts and better integrate development with the natural terrain (see Sections 16.24.060(D), 16.24.060(E), 16.24.060(G), and 16.24.070).
• Defers broader citywide retaining wall policy updates to a future ordinance while implementing targeted interim refinements applicable to hillside areas (see Recitals dated November 18, 2025 and February 3, 2026, and Section 16.24.060(E)).
• Advances transparency and regulatory clarity while balancing state housing law compliance, private property rights, fire safety requirements, and preservation of Murrieta’s scenic hillside character (see Sections 16.24.010, 16.24.020, 16.24.050(C), and 16.24.070).
• These updates represent a significant shift toward transparency and regulatory clarity, aligning local code with state housing laws while balancing private property rights and at the same time addressing Murrieta's scenic hillside character.
The draft ordinance presented to the Planning Commission (Commission) in 2023 has been revised following workshops with the City Council. Staff are returning to the Commission for reintroduction of the ordinance and a new recommendation to the City Council on the Hillside Updates consistent with the direction received.
BACKGROUND
In August 1996, the City Council retained a design consultant to assist in preparing a new zoning code. By September 1997, following several joint public workshops with the Planning Commission and City Council to gather input and establish development standards, the City initiated the adoption process for a comprehensive Development Code. In early 1998, the City implemented new zoning and development regulations, replacing Riverside County Ordinance No. 348. These regulations included provisions addressing hillside development. Aside from minor amendments in 2003, the City’s hillside development standards have remained largely unchanged since their original adoption.
At the time of adoption, the standards were applied on a citywide basis rather than being limited to specifically designated hillside areas. Additionally, the City lacked the tools to independently identify hillside areas. Although a map depicting hillside features was later developed, it was never formally codified within the Municipal Code. While this map has been used historically during project review, questions have persisted regarding its accuracy. Advances in technology now allow for precise identification of hillside areas on a citywide basis through geographic information systems (GIS).
Over time, staff have identified inconsistencies across various sections of the Municipal Code including the Development Code, leading to conflicting interpretations of existing standards. For example, applicants have noted that the City’s hillside development and general height regulations are complex and inconsistently applied.
The primary objective of the proposed updates is to revise the development standards to ensure they are clear, accurate, and user-friendly for both applicants and staff. The proposed modifications are intended to improve clarity, resolve inconsistencies, incorporate best practices, and streamline regulatory requirements.
On March 29, 2022, during its annual priority goals workshop, the City Council directed staff to review the hillside development standards due to concerns regarding their interpretation. The City’s current hillside regulations are codified in Chapter 16.24, “Hillside Development,” of the Development Code. The proposed updates have since been reviewed and approved by the Riverside County Airport Land Use Commission (Attachment 2). Additionally, the City has created a dedicated webpage to inform the public about the proposed modifications, available at: <https://www.murrietaca.gov/1314/Hillside>.
Development Advisory Group
On August 25, 2022, staff presented an overview of the proposed Development Code amendments to the Development Advisory Group (DAG) to solicit feedback on the draft standards. The group generally agreed that the proposed revisions would help clarify the applicability of hillside development standards.
WRCOG Assistance
Staff also notes that the effort benefited from consultant support funded through a grant program administered by the Western Riverside Council of Governments (WRCOG). Through this program, the City was able to obtain updated graphic exhibits included in the draft Ordinance by working with PlaceWorks, at no cost to the City.
Planning Commission - Workshop 1
This item was continued from the December 14, 2022 meeting. No report or presentation was provided.
Planning Commission - Workshop 2
On January 25, 2023, staff presented a workshop to the Commission outlining proposed updates to the Municipal Code in advance of a future public hearing, with the goal of obtaining feedback on key issues and potential revisions. Major discussion topics included resolving building height measurement conflicts through a consistent grade reference, implementing GIS-based hillside and ridgeline mapping, replacing average slope calculations with GIS data, and identifying screening techniques for ridgeline development. Staff also introduced broader updates to improve code clarity, incorporate graphics, address inconsistencies, apply best practices, and simplify standards.
Community Outreach Workshop
On April 11, 2023, staff conducted a public workshop at the Alderwood Park Clubhouse to present the existing and proposed hillside development standards and solicit additional community feedback. This outreach was undertaken at the direction of the Planning Commission to promote transparency and broaden public input. The presentation addressed topics including the applicability of the Hillside Overlay, structure height limits and measurement methods, slope applicability, elimination of average slope calculations, identification of prominent ridgelines, and updated retaining wall standards. The workshop concluded with a question-and-answer session to gather community feedback.
Planning Commission - Ordinance Recommendation
On June 28th, 2023, the Commission held a duly noticed public hearing on the proposed Development Code Amendment as it relates to hillside development. Staff highlighted the historical evolution of hillside regulations since the 1990s and identified key issues, including overly complex requirements, inconsistent interpretation, and the need to better target regulations within designated hillside overlay areas. The update includes technical revisions related to building height, retaining walls, setbacks, line-of-sight requirements, and landscaping, with a shift toward a more objective, GIS-based framework supported by the Hillside Overlay Map and Prominent Ridgelines Map.
The Commission and public discussed design considerations and policy implications, including alternatives to large retaining walls and concerns about property impacts from mapped overlays. Public speakers urged flexibility and cautioned against rigid mapping, while staff emphasized balancing preservation with development feasibility.
City Council - Workshop 1
On August 15, 2023, the City Council hosted its first workshop on this item. The City Council requested additional information. Council members and staff discussed key standards for retaining wall heights, specifically discussing a 6-foot baseline and the balance between aesthetic landscaping and mandatory fire safety fuel modification zones. The session aimed to replace subjective guidelines with objective criteria for building upon slopes, ensuring that new developments preserve the city’s visual ridgelines while providing a clearer, more predictable path for project approvals. The workshop was continued to a future meeting date.
City Council - Workshop 2
On March 5, 2024, the City Council hosted a second workshop on this item. The discussion centered on a potential review process for retaining walls, clarifying building height measurements on sloped terrain, and ensuring the "Hillside Overlay" maps accurately reflect local topography to avoid unnecessary burdens on flat-land homeowners. Crucially, the Council worked to harmonize aesthetic screening requirements with mandatory state fire safety and fuel modification mandates, prioritizing the protection of prominent ridgelines while ensuring the code aligns with current California law. Due to additional time needed for the discussion and feedback, the workshop was continued for a second time
City Council - Workshop 3
On June 17, 2025, the City Council hosted a third workshop on this item. Staff explained that the existing 30-year-old regulations are plagued by inconsistencies and lack an official overlay map, leading to unpredictable reviews and hindered development. The proposed update utilizes modern GIS technology to establish a codified Hillside Overlay Map and introduces more objective criteria for measuring building heights and wall placement. The goal is to streamline the review process, align with current fire and safety codes, and provide developers with a clear, predictable framework that eliminates the ambiguity found in the current development code.
The workshop also addressed specific design concerns, particularly regarding retaining walls and their aesthetic impact. Council members debated the merits of "living walls" versus traditional structures, with some expressing strong opposition to "monolithic" walls that disrupt the natural landscape. Staff clarified that while the ordinance aims to protect scenic vistas and manage environmental hazards like wildfire and erosion, it would not retroactively affect existing specific plans, such as Greer Ranch, which maintain their own customized standards. The Council emphasized balancing property rights with the city's long-term goal of guiding responsible hillside development without creating "impossible" scenarios for landowners/investors.
City Council - Workshop 4
On October 21, 2025, the City Council held its fourth workshop on this item and reached consensus to adopt a 25% slope threshold for Hillside Areas, replacing the inconsistent 20% standard. To provide clarity and reduce bureaucratic hurdles, the Council directed staff to move away from city-wide application and instead implement a codified Hillside Area Map. By confining these standards to the hillside map, the city exempts properties in flatter areas from the regulatory burden and expense of unnecessary slope evaluations.
The Council emphasized that the updated ordinance should focus on objective design guidelines rather than restrictive prohibitions, aiming to balance property rights with the General Plan’s goal of preserving natural hillside areas. Members specifically requested that staff differentiate between developed and undeveloped land, ensuring that existing homeowners aren't unfairly burdened while still maintaining the city’s aesthetic integrity.
City Council - Workshop 5
On November 18, 2025, the City Council conducted its fifth workshop on this item, during which it identified several key policy directions and considerations, including that updates to retaining wall regulations should be applied citywide rather than limited to Hillside Areas; that standards should balance flexibility through defined options with sufficient specificity, particularly regarding retaining wall design; that retaining wall design standards should be implemented on a citywide basis; that color palettes should generally consist of muted tones with pre-established shades or blends to ensure a consistent and desirable aesthetic; that earthtone colors may be appropriate for hillside structures; that retaining walls exceeding six feet in height may, in certain circumstances, may be excessive citywide; that tiered retaining walls incorporating landscaping are preferred; that Keystone-style walls with integrated landscaping are also desirable; that landscaping is a priority for the Council, including the use of larger plant sizes earlier in the development process; that additional clarification from the Fire Department is needed regarding planting requirements within Fuel Modification Plans; and that distinctions between rural residential and tract home front-yard setbacks should be more clearly defined.
City Council - Workshop 6
On February 3, 2026, the City Council held its sixth and final workshop on the topic. The City Council discussed key topics, including retaining walls, landscaping standards, fire severity zones, distinctions between developed and undeveloped properties, and the relationship between hillside and citywide standards. Public input raised concerns about the visual and regulatory impacts of retaining walls, tree removal credits, definitions of undisturbed land, conditions of approval, and broader issues such as Senate Bill 9 (administrative approval of lot splits) and insurance implications. Following that discussion, the Council reached consensus to provide direction on specific retaining wall types (including geogrid, CMU, and keystone walls) are design options for hillside areas but wanted to maintain flexibility on what that ultimate design is for the applicant, suggested requiring earlier installation of larger landscaping, and that a separate ordinance was needed on a city-wide basis as it relates to retaining walls, along with direction to staff that the definitions of developed and undeveloped land for hillside areas need to be clearly defined.
ANALYSIS
The following analysis provides a comprehensive overview of the main proposed modifications that have been previously introduced and discussed at City Council, Planning Commission, and community workshops. These discussions have helped shape and refine the direction of the proposed amendments through policy guidance, technical input, and community feedback.
In addition to addressing these key substantive changes, this analysis also includes a summary of more minor, non-substantive modifications. These typically consist of clarifications, organizational improvements, and technical edits intended to enhance the overall clarity, consistency, and usability of the regulations without altering their underlying intent. Collectively, this document is intended to present a clear and transparent account of both the major policy considerations and the supporting refinements incorporated into the proposed updates.
Summary of Code Changes - Chapters 8.20 and 15.52 (For Informational Purposes Only - Limited to City Council Review) (Attachments 7 and 8):
• Updates to Section §8.20.030 “Declaration of Nuisance”
o Code Enforcement Division’s request to address revegetation of sloped areas after a catastrophic event.
o Following a catastrophic event causing a loss of vegetation (i.e., wildfire, landslide, etc.), all impacted sloped areas of a subject parcel shall be revegetated to prevent further erosion pursuant to Section 16.28.080 “Landscaping Standards”.
• Updates to Section §15.52.020 “Definitions” for Consistency
o Clarification of a definition for “Hillside Area” and “Hillside Site” for consistency with the proposed updates under Chapter 16.
o “Hillside Area,” means those areas specifically designated in a Hillside Overlay as adopted by the City.
Summary of Code Changes - Title 16 (Attachments 1.3 and 1.4):
The proposed code amendments are intended to refine and improve the existing Hillside Development regulations by clarifying their applicability, eliminating redundancies, and revising specific code sections for greater clarity and internal consistency. In addition, the updates seek to streamline applicable review procedures to improve administrative efficiency while maintaining the original regulatory intent.
A summary of the proposed changes is provided below. For ease of reference, the modifications are organized in a manner that corresponds directly with the structure and sequence of the attached Ordinance Amendment, allowing for a clear comparison between the existing provisions and the proposed revisions:
• Updates to Development Standards Table Updates: Tables 16.08-3, 16.08-4, and 16.14-2
o Addition of footnotes on where to find the maximum building height in the Code, and if the property is within a “Hillside Area”.
o Updates Section §16.08.020 “Residential Districts General Development Standards”, Table 16.08-03 “Residential (Single-Family) Zones General Development Standards” refers to this footnote.
o Updates Section §16.08.020 “Residential Districts General Development Standards”, Table 16.08-04 “Residential (Multi-Family) Zones General Development Standards” refers to this footnote.
o Section §16.14.010 “Purpose”, Table 16.14-2 “Special Purpose Districts General Development Standards” refers to this footnote as well.
• Updates to Section §16.18.080 “Height Measurement and Height Limit Exceptions”
Background:
The current standard may be ambiguous as to when the City’s Hillside Development standards apply. Relatedly, Chapter 16.24 could be misapplied beyond the maximum slope height criteria as identified under Section 16.18.080 “Height Measurement and Height Limit Exceptions”. Staff is aware of an inconsistent interpretation regarding how an applicant would measure a slope under a 14.3 percent slope (one foot rise or fall in 7 feet). The measurement for a building pad would remain unchanged with these proposed modifications.
Prior Community, Planning Commission, and City Council Workshops:
Based on prior feedback, staff has proposed the following updates to establish consistent and objective standards for measuring building height on both sloped terrain and graded pads, regardless of the specific slope percentage. The intent is to eliminate ambiguity in height calculations and ensure a uniform application of development standards across varying site conditions. Under this framework, properties located outside of the designated Hillside Overlay area would be governed by the maximum building height limits established within the applicable underlying zoning district.
For properties located within the mapped Hillside Overlay area, a more restrictive standard would apply in recognition of the unique visual, environmental, and topographic components associated with steeper terrain. Specifically, a maximum building height of 30 feet would be imposed for development on slopes exceeding 25 percent. This approach reflects a balance between allowing reasonable development and preserving hillside character, scenic resources, and neighborhood compatibility. It is also consistent with prior policy direction, as both the City Council and Planning Commission have previously indicated support for incorporating this methodology into the proposed Ordinance amendment.
Proposed Modifications / Discussion:
Section 16.18.080 (Height Measurement and Height Limit Exceptions) of the Murrieta Municipal Code (MMC) is hereby amended to read as follows:
Height Measurement on a Slope
o The structure height measurement is the difference in elevation between the highest and the lowest “Adjacent Ground Elevation” located five feet from the building. If the actual grade difference exceeds 10 feet, a maximum of 10 feet may be added to the maximum allowable height per the zone to accommodate areas such as crawl spaces. Additionally, staff is proposing, under this scenario, chimneys, vent pipes, etc., would be permitted to exceed this limit up to 15 percent as provided currently under MMC
§16.18.080.C. - “Exceptions to Height Limits.” This approach reduces grading in some respects and promotes a grading design that follows natural grades.
o If the difference in elevation is 10 feet or less, the reference grade height is established at the highest “Adjacent Ground Elevation”. Figures 16.18-2 and 16.18-4.
o If the difference in elevation is greater than 10 feet, the reference grade height is established at 10 feet above the lowest “Adjacent Ground Elevation”. Figures 16.18- 3 and 16.18-5.
o Provides some flexibility to account for some subterranean areas that one would encounter on a sloped property (i.e., crawl space areas below a stem wall).
o Provides some flexibility for someone to have a covered elevated deck or balcony within this height envelope.
o For where there are steeper slopes, where the elevation difference is 10 feet or greater, the measurement envelope tightens as height would pull back with the slope. This would minimize the overall height.
o For gentler slopes where there is a differential of less than or equal to 10 feet, it accounts for slight variation at a building site.
o On a very steep lot, it may limit the height of the building on the highest uphill side.
Building Pad
o For a proposed building pad location, the height of the building is the vertical distance from the finished grade to the height of the roof line.
o The finished grade is a known metric and easily identifiable element.
o This mirrors the current standard, and it is a simple approach for both a project applicant and City staff.
o This is a relatively easy standard for an applicant to show compliance with elevations and height measurements on a standard set of plans.
Basement Definition
o Definition needed per City’s Building Official
o Plays a key role in building and life-safety compliance under the California Building Standards Commission codes (including the California Building Code and Residential Code). Basement classification can affect requirements for:
Ø Emergency escape and rescue openings (egress windows)
Ø Fire-resistance and separation
Ø Ventilation and natural light
Ø Ceiling heights and habitability standards
• Updates to Section §16.22.050 “Measurement of Fence or Wall Height”
o Provides clarification that the measurement criteria under Section §16.18.080 (Height Measurement and Height Limit Exceptions), which is to utilize the standards under Chapter 16.24 for parcels located within the Hillside Overlay.
o Provides parameters for when there is a difference in the ground level between two adjacent parcels and how that is determined.
• Minor Modifications to Section §16.24.010 “Purpose”
o Minor typographical updates with capitalization and italicization are provided to reference a given definition.
• Updates to Section §16.24.020 “Applicability”
Background:
The issue is MMC §16.24.060.A under “Hillside Slope Categories” applies the “Hillside Condition” to all natural slopes within the threshold of 25% slope up to 50% slope throughout the City (no development is permitted on slopes over 50%). Staff understands that the intent of this original criteria was for it to be limited to mapped areas (see below image and Attachment 3) within the Hillside Overlay, not on a citywide basis. The other issue is that this map was never codified within the MMC, which should have been the case to facilitate project review by both City staff and project applicants.
Prior Community, Planning Commission, and City Council Workshops:
Staff recommended refining the applicability of the Hillside Overlay standards so that they apply only to specifically mapped areas with slopes of 25 percent or greater, rather than citywide. This direction is consistent with feedback provided during the March 29, 2022, City Council annual priority goals workshop and was reaffirmed at Council Workshop 4, where the Council confirmed that a 25 percent slope is the appropriate threshold for defining hillside areas, as opposed to a 20 percent threshold where that was referenced once in the MMC. To promote consistency and accuracy in project review, staff further recommended using the City’s GIS platform to delineate these areas based on two-foot contour intervals. This methodology establishes a precise and objective basis for determining where hillside regulations apply, thereby reducing ambiguity for both applicants and staff.
Additionally, members of the public recommended incorporating cross-references to applicable Specific Plans to ensure that any relevant hillside development standards are clearly identified. This approach, also confirmed at Council Workshop 4, would improve accuracy, where Specific Plan provisions may modify or supplement the base hillside regulations. Overall, feedback from prior workshops was positive, with a general consensus that formalizing the overlay through mapping, along with integrating cross-referencing to the Specific Plan, would enhance clarity, streamline implementation, and provide a more consistent framework for evaluating development proposals.
Proposed Modifications / Discussion:
Staff proposes the implementation of the following modifications, to bring clarity to the issue:
o Utilization of Geographic Information System (GIS) for identification of mapped “Hillside Areas”.
o Updates to MMC which address the existing discrepancy with a 20 percent slope being referenced, versus the 25 percent slope as described for the Hillside Overlay Area. This has been a key issue of misunderstanding and applicability in the past with respect to project review.
o Updates to Section §16.24.020. The updates help to clarify that the hillside overlay criteria is to only apply to those areas that are located within the Hillside Overlay.
• Updates to Section §16.24.030 “Definitions” Removal of Average Slope Calculation
Background:
As part of the definitions updates, it has been brought to staff’s attention that the following calculation may have been misinterpreted or misapplied for determining a slope.
Prior Community, Planning Commission, and City Council Workshops:
At prior Community Workshops, Planning Commission workshop, and City Council workshops, including most recently and reconfirmed at Council Workshop 4, the use of Geographic Information Systems (GIS) mapping was discussed in detail as a preferred method to replace the traditional average slope calculation approach. This shift reflects an effort to improve consistency, accuracy, and efficiency in evaluating hillside conditions by relying on standardized, City-maintained spatial data rather than project-by-project calculations that may vary depending on methodology or interpretation. The use of GIS allows for slope analysis derived from high-resolution contour data, providing a more objective and transparent basis for determining whether a property meets applicable hillside thresholds.
With this proposed modification, the City recognizes that unique site conditions or data limitations may occasionally result in discrepancies or disputes regarding mapped slope classifications. In such cases, the City Engineer may authorize the use of an alternative technical method to verify slope conditions. This may include preparinga detailed analysis using a CAD-based program or a similar tool that applies to the conventional average slope formula. Allowing this flexibility ensures that applicants have a clear and equitable path to demonstrate site-specific conditions while maintaining the overall intent of standardized slope evaluation procedures.
Proposed Modifications / Discussion:
The proposed modifications would eliminate the existing average slope formula from the MMC. As noted in the introduction to this discussion item, advances in technology have rendered the formula largely unnecessary, as slope conditions can now be accurately and efficiently mapped using the City’s Geographic Information Systems (GIS) with two-foot contour data. This approach provides a more consistent, streamlined method for evaluating hillside conditions, reducing calculation variability and improving clarity for both applicants and reviewing staff. By relying on standardized GIS-based mapping, the review process becomes more transparent and less time-intensive. The City acknowledges that there may be instances where discrepancies arise or where site-specific conditions are not fully captured by the mapped data. In such cases, the City Engineer may authorize the use of an alternative technical analysis to verify slope conditions. This may include using a CAD-based program or a similar analytical tool that applies the traditional average slope formula. This provision ensures flexibility in addressing unique circumstances while maintaining the overall intent of simplifying and modernizing the slope evaluation process.
• Other Definition Updates:
o Provides new definitions consistent with other portions of the MMC, including “City”, “City Engineer”, “City Manager”, and “Director”.
o Corrects/updates existing definitions consistent with other portions of the MMC.
o Updates provided to Figure 16.24-1 (Slope Examples) with the inclusion of a new 4:1, 25 percent slope example and clearer graphics.
• Updates to Section §16.24.040 “Application Submittal Requirements”
o Updates to Section §16.24.040. This covers existing standards for the submittal of a natural features map, a conception grading plan, a drainage map, a slope analysis map, slope profile drawings, data sources, provisions for a geotechnical report, objective design guidelines, criteria for when no grading is required, and additional information that may be needed.
o The proposed language shifts the standard from a subjective interpretation to clearly defined, objective criteria. This approach promotes consistency and predictability in application and review and aligns with recent State housing legislation that requires jurisdictions to rely on objective standards in evaluating housing development proposals.
• Updates to Section §16.24.050 “Project Review Procedures”
o Cross-referencing to the Hillside Overlay Map for applicability.
o Clarification of “Commission” to mean “Planning Commission”.
o Updates with referencing to objective criteria consistent with recent State housing legislation, versus existing subjective criteria and requirements.
Prior Community, Planning Commission, and City Council Workshops:
Updating the citywide retaining wall standards is an important topic for all stakeholders involved. This topic has been covered at numerous points during the outreach process as it relates to this hillside updates project. Most recently, it was covered in detail at Council Workshops 5 and 6. Some of the takeaways from Council Workshop 5 was that flexibility was needed with defined options, while providing some specifics as it relates to retaining walls; colors should generally be muted as they relate to retaining walls, and exact shades or blends should be defined upfront to ensure a consistent and desirable appearance; retaining walls over six feet in height may be too high in some circumstances; having landscaping retaining wall tiers is a desired design element; landscaping is important for the Council; and establishment of larger planting sizes earlier in the development process is a desired outcome.
At Council Workshop 6, the City Council determined that a comprehensive, citywide amendment to the retaining wall standards should not be included as part of the proposed hillside code updates. The Council expressed that the overall retaining wall updates present a broader and more complex set of issues, often involving site-specific constraints, engineering considerations, and neighborhood compatibility, that warrant a more focused and standalone evaluation apart from this code amendment. As such, any substantive overhaul of retaining wall regulations will be deferred to a future effort, where these unique circumstances can be more thoroughly studied and addressed as a separate topic.
The workshop yielded several important policy considerations to help guide future code development. Notably, the Council emphasized the need for an administrative review process for retaining walls exceeding six feet in height, if certain circumstances warrant the additional height. This waiver/modification process mirrors the City’s current approach, as described in Section 16.22.090 (Authority to Waive or Modify Requirements) of the MMC, as it relates to fencing standards. This approach would provide an opportunity to evaluate potential visual, structural, and environmental impacts on a case-by-case basis in hillside areas.
Additionally, the Council directed staff to incorporate illustrative examples and design options for wall treatments within the Code, which has been provided. The intent is to promote higher-quality design, encourage aesthetic consistency, and mitigate the visual massing of taller retaining walls through the use of muted colors, articulation, landscaping, and other context-sensitive design features.
Proposed Modifications / Discussion:
The proposed standards would apply only within designated Hillside Areas. The table above can be summarized as follows:
o Front and street-side setbacks: Retaining walls would be limited to a maximum height of 3 feet. This maintains the existing standard while extending it to explicitly include street-side setbacks.
o Line-of-sight areas: A maximum height of 30 inches would be required to preserve visibility and address safety concerns. This reflects current engineering practice and is clarified here for consistency.
o Terraced walls: Individual retaining walls within a terraced configuration would be limited to 6 feet in height, consistent with existing regulations; however, there is a new waiver/modification process if the wall needs to exceed this height restriction.
o Walls exceeding 6 feet: Retaining walls over 6 feet in height may be permitted when integrated into a structure; however, their visual impact must be mitigated through contour grading and appropriate landscaping. This approach aligns with current standards.
o Horizontal separation: Retaining walls that are 6 feet in height must be separated by a minimum horizontal distance of 6 feet. This requirement remains unchanged from the current code.
o Design criteria reference: The final row provides a cross-reference to the uniform retaining wall design standards described earlier in this staff report.
Other General Updates to Section
o Updates to Table 16.24-1 (Hillside Development Standards) for criteria.
o Updates to site design and roadway placement for consistency with the current California Fire Code and City standards.
o Minor updates for cross-lot profiles, which cover the building envelope for a structure on a downhill lot, the building envelope for an uphill lot, and the building envelope at cross-lot slopes.
o Minor updates for walls and fencing criteria. Refers to Section §16.22.070.F (Retaining Walls) for additional criteria and for consistency with citywide design standards for retaining walls.
o Cross-referencing for consistency with citywide landscaping standards at sloped areas and use of drought-tolerant and fire-resistant landscaping materials.
o Updates for grading techniques at hillside areas, drainage improvements at hillside areas, and for public safety.
• Updates to Section §16.24.070 Hillside Development Guidelines
o Minor updates for the site design and building placement of a residence at a site on a slope. Buildings are encouraged to be placed parallel to the slope, and not counter to it, which is the current guidance.
o Minor updates to roadway placement at hillside locations. Placement is encouraged to work with the terrain and not counter to it. These are the current parameters.
o Minor updates to grading techniques examples, which relate to minimal grading, contour grading, landform grading techniques, as well as drainage improvements in a more objective and naturalized manner.
o Cross-referencing of unifying standards for all zones with respect to landscaping on sloped areas.
• New Section §16.24.080 “Exceptions”
o Clarifying that the Chapter does not apply to residential accessory structures or accessory dwelling units on parcels with existing development approvals, provided that the proposed construction does not require a retaining wall and complies with the applicable standards and exemptions outlined in Sections 16.44.150, 16.44.160, and 16.02.020.
• New Section §16.24.090 “Reserved”
o Reserved blank section for future hillside updates/amendments.
• New Section §16.24.100 “Hillside Overlay Map”
o Codifies the Hillside Overlay Map within the MMC. This has been missing to this point, which has made it challenging for City staff and project applicants to reference.
o Provided that these updates are approved, staff will work with Code publisher on uploading a high-resolution image.
o This information will also be incorporated into the City’s online Geographic Information System (GIS) as a layer for future reference, which will assist City staff and project applicants.
Conclusion
The changes proposed in this update are intended to reconcile the various code sections and achieve consistency throughout the Development Code (Title 16), as well as the Municipal Code (Chapter 15.52) for hillside standards. With the implementation of these updates, clarity will be provided to residents and project applicants on which standards apply and where, addressing the current lack of clarity regarding hillside development. Lastly, with the application of the proposed modifications covered in this ordinance amendment, it will continue to preserve the visual and aesthetic quality of hillsides and ridgelines as viewed from the surrounding community and avoid and minimize site disturbance at these locations to the extent feasible.
NOTICING
The Project was noticed in compliance with Section 16.76 of the Development Code, including sending the notice to all properties within the Hillside Area Overlay, and publication occurred within a newspaper a minimum of 10 days prior to the hearing and posting of the agenda (Attachment 8).
ATTACHMENTS
Attachment 1 - Hillside Updates Resolution
Attachment 2 - Exhibit A - Hillside Updates Ord. Clean Title 16
Attachment 3 - Exhibit B - Hillside Updates Ord. Redline Title 16
Attachment 4 - Hillside Updates - 15162 Consistency Analysis
Attachment 5 - Hillside Updates - Subsequent NOD
Attachment 6 - Ord. Clean Title 8 and 15 (For Info. Purposes Only)
Attachment 7 - Ord. Redline Title 8 and 15 (For Info. Purposes Only)
Attachment 8 - Hillside Updates PC Public Notice - May 13, 2026