Menifee | Hillside, Quail Valley and Fire Zones

Menifee, California Hillside, Quail Valley and Fire Zones: Steep Slope Limits, the Hillside Plot Plan, the Quail Valley Septic Ban and Fire Hazard Rules

Three local conditions can stop or reshape a Menifee project before the zone rules are even reached: steep hillsides, the septic system ban in Quail Valley, and fire hazard zones. Each is handled by a different body. The City writes the hillside rules in Chapter 9.190 of the Development Code, in Article 4. The Santa Ana Regional Water Quality Control Board, a state agency, controls septic systems in Quail Valley, and the City explains the rule on its Quail Valley Moratorium page. Fire hazard zones come from state maps that the City Council approved for Menifee by ordinance in June 2025. This page sets out what each one means for ADUs, SB 9 homes, small lot maps and new houses. The Menifee overview has the summary.

Where the Hillside Rules Apply

Chapter 9.190 applies "to all development on properties in Menifee that contain significant areas of steep slopes and prominent hillsides and ridgelines" within the areas shown on Figure 9.190.020-1, the Menifee Hillside Map. The chapter says these features "are typical of the properties in the Rural Mountainous (RM) and Rural Residential, 5-acre minimum (RR5) zones, but not limited to these areas." Article 6 defines a steep slope as land with a gradient of at least 25 percent, meaning "25 feet of vertical distance for every 100 feet of horizontal distance," and at least 50 feet of vertical rise. A ridgeline is "an elongated crest, or series of crests, with or without individual peaks, significantly higher than the adjoining ground."

Section 9.190.030 exempts development that stays "a minimum of 50 feet from the top of any steep slope or hillside and is no closer than 200 feet horizontally and 50 feet vertically from prominent ridgelines." It also exempts projects with a valid map, grading permit or other approval consistent with the rules before the General Plan update of December 18, 2013, open space and trails on City land, some access roads and utility lines, and fire clearance that keeps the native root stock.

Development that is not exempt "shall require plot plan approval pursuant to Chapter 9.80," and the application must include a plot plan by a licensed surveyor or civil engineer, a grading plan, a topographic map at a scale of at least 1 inch to 100 feet with contours no more than 10 feet apart, a slope analysis in four bands (0 to 24, 25 to 34, 35 to 50 and over 50 percent), a biological report, a cultural resources report by a qualified archeologist, photographs, an erosion control plan, a landscape and habitat restoration plan, architectural and lighting plans, a line of sight visual analysis, and a fuel modification plan.

Hillside Development Standards

Section 9.190.060 sets the limits for development that encroaches on steep slopes, hillsides or ridgelines:

• Ridgelines. "Areas situated within 200 feet horizontally and 50 feet vertically of a hilltop or ridgeline shall not be disturbed."
• Roofs and slopes. "The horizontal distance between a natural or graded steep slope and a roof, or portion thereof, shall not be less than 20 feet."
• Graded slopes. A graded slope in areas of natural steep slopes "shall not exceed 30 feet" in height.
• Blasting. Blasting for roads or pads "shall be strongly discouraged," and grading kept to a minimum.
• Height. "No dwelling, building or structure shall have more than two stories." On a terraced pad the limit is "40 feet measured from the lowest finished floor level, excluding any basement areas."
• Subdivisions. Each new lot needs "some portion that does not contain steep hillsides" big enough for a home, and later encroachment on a lot is counted against the original subdivision. Cluster subdivisions under Chapter 9.170 are "encouraged."

The share of the steep slope land that may be disturbed depends on how much of the lot is steep:

Source: Table 9.190.060-1, Menifee Development Code Article 4, PDF file dated 8-15-24. "An additional 2% may be added" where the existing development area is not contiguous or has no direct access to a public right-of-way.

As VanPlex arithmetic, on a 5-acre RR5 lot with 4 acres of steep slope land, 80 percent of the lot is steep, so up to 12 percent of the 4 acres, or 0.48 acre, may be disturbed. The approving authority may grant relief from the standards at a public hearing if the applicant shows an alternative that "complies with and furthers the intent" of the chapter and is "equivalent to or better than" the standards. The chapter also applies the "Menifee Steep Hillside Guidelines" and the hillside section of the Menifee Design Guidelines, which this guide did not read.

Hillside Rules and State Housing Laws

The hillside chapter reaches the state housing routes too. Section 9.296.060 lists Chapter 9.190, Hillside Development Standards, among the chapters that apply to SB 9 two-unit projects, and Section 9.298.040 lists it for small lot subdivisions. An ADU follows the zone standards in Section 9.295.020, and an ADU on a steep site may need the hillside plot plan for its grading. Under state law a city may apply only objective standards to these projects, and the slope and distance limits above are numeric (VanPlex reading). The Steep Hillside Guidelines, if they hold judgment-based design rules, would not bind a ministerial project; ask the City.

The Quail Valley Septic Ban

Quail Valley is a neighborhood of Menifee where many homes use septic tanks. The City's Quail Valley page says that "In 2005 The Santa Ana Regional Water Quality Board placed a moratorium on septic systems in the Quail Valley area due to failing septic tanks contaminating Canyon Lake," and that no new septic systems could be installed "until two areas of the community receive sewer." A moratorium is a temporary ban. The Eastern Municipal Water District later installed sewer in part of subarea 9, and the board amended the rule.

Sources: City of Menifee, Quail Valley Moratorium page; Santa Ana Regional Water Quality Control Board, notice "Quail Valley Amendment Is Now in Effect".

The board's notice says "Discharges from new septic systems (also known as Onsite Wastewater Treatment Systems or OWTS) continue to be prohibited in Quail Valley," with the exemptions above. It says the amendment was "approved by the Santa Ana Regional Water Quality Control Board on January 16, 2020," and that the Office of Administrative Law approved it on September 14, 2020. The City page directs owners to Riverside County Environmental Health to find out whether a property can meet the conditions, and the board's notice includes a map of the subareas.

What the Septic Ban Means for New Homes

• ADUs. Section 9.295.020(E)(2)(p) says ADUs "shall not be permitted in those areas of the city which have significant problems with regard to water availability or quality, sewage disposal or other public health or safety concerns," including areas under a sewer moratorium. In Quail Valley subareas 4 and 9, an ADU needs a sewer connection (VanPlex reading).
• ADUs on septic elsewhere. An ADU on a septic system needs "a percolation test completed within the last five years," or within 10 years if recertified, and written approval from Riverside County Environmental Health.
• SB 9 two-unit projects. Section 9.296.060 says two-unit developments "shall be required to connect to sewer and shall not be permitted where sewer is not available." That rule applies citywide, so a septic-only lot anywhere in Menifee cannot use the two-unit route.
• SB 9 lot splits and small lot maps. Each new parcel must have "separate sewer, water, gas, and electrical utility services" and be able to connect before approval.
• Hillside utilities. The hillside chapter exempts utility lines, but its exemption leaves out septic systems unless the county certifies that no grading or benching is needed.

Fire Hazard Severity Zones

Fire hazard severity zones are mapped areas rated by fire danger. The minutes of June 18, 2025, printed in the July 16, 2025 packet, record that the City Council "Adopted Ordinance No. 2025-416, approving of the Fire Hazard Severity Zone Maps in the Local Responsibility Areas for the City of Menifee." The City Council agenda of November 19, 2025 then lists an ordinance "Adopting by Reference the 2025 California Fire and California Wildland-Urban Interface Codes" for second reading and adoption. This guide did not read the maps, so it cannot say which lots are mapped.

Sources: Menifee Development Code Sections 9.296.040 and 9.296.060 and Chapter 9.190; Section 9.298.030 and 9.298.040 in Ordinance LR24-0135; Multifamily Objective Design Standards, Section 1.3.

The SB 9 rule in Section 9.296.040 excludes a lot "Within a very high fire hazard severity zone, unless the site complies with all fire-hazard mitigation measures required by applicable building code standards." For two-unit projects in that zone, "Emergency access and water supply requirements shall comply with the California Code of Regulations, Title 14 and Title 24, Part 9," and new structures follow the building code for that zone. The 2025 small lot chapter applies the same measures to lots "in a very high or high fire hazard severity zone."

Where the Code and City Documents Disagree

• Wrong section numbers in Chapter 9.190. Section 9.190.040 requires a plot plan for development "that is not exempt per Section 9.155.020"; the exemptions are in Section 9.190.030. Section 9.190.060 cites "Table 9.90.060-1" for the table numbered 9.190.060-1, and Section 9.190.070 grants relief from "Section 9.290.060," which is the wireless facilities chapter. Read each as the hillside section (VanPlex reading).
• Hillside pointer in the SB 9 and small lot chapters. Sections 9.296.040 and 9.298.030 send lots in the "Hillside Overlay" to "Chapter 9.195," which is Landscaping Standards.
• Date of the Quail Valley amendment. The City page says the water board "passed an amendment" on September 14, 2020. The board's notice gives January 16, 2020 for the board's approval and September 14, 2020 for approval by the Office of Administrative Law, the date the amendment took effect.

Where to Go Next

Related on VanPlex: the Menifee overview, the California SB 9 page and the California ADU law page.

Frequently Asked Questions

Official sources (checked October 2026)