ADU Constructionin Menifee, CA
ADU construction in Menifee follows state ADU law plus a City ordinance that the City's own papers describe two ways: 1,500 square feet and 18 feet in the code text, 1,200 square feet and 16 feet in the June 2026 Guidebook. The City must decide a complete application within 60 days. Confirm size with Planning before drawing.
Menifee is mostly single-family houses. The Census Bureau's 2024 one-year estimates count 41,467 homes, and 84.4 percent of them, 35,008, are single-family detached houses, with another 1,201 attached. Owners live in 78.5 percent of occupied homes. The margin of error on the total is plus or minus 2,561, so read the counts as approximate. About 52.2 percent of the homes were built in 2000 or later, and about 18.8 percent before 1980.
The City is young, established on October 1, 2008 as Riverside County's 26th city, and its ADU rules are younger still: Ordinance 2024-384 was adopted on February 7, 2024. This page covers the state letter that questions that ordinance, the size and height conflict in the City's own documents, the free plan program, septic and sewer, garage conversions, fire and hillside checks and the money. Costs and phases are on our ADU construction page. All City details come from menifee.ca.gov pages and handouts read in November 2026.
Menifee Planning and Building rules that apply to ADU construction
Where adu construction permits come from in Menifee: City of Menifee Community Development Department, Building & Safety Division.
- Menifee's ADU code (Development Code 9.295.020, Ordinance 2024-384 adopted February 7, 2024) says ADU and JADU permits are 'considered ministerially, without discretionary review or a hearing', and the City must approve or deny within 60 days of a completed application when there is an existing single-family home. A denial must come with a written list of defects. A permit cannot be denied for correcting nonconforming zoning, code violations or unpermitted structures that do not threaten health and safety.
- Menifee's code (read from the City's Encode site) allows a detached or attached ADU up to 1,500 square feet, detached height up to 18 feet (20 feet within 1/2 mile walking distance of a major transit stop, 25 feet for attached), four foot side and rear setbacks, one off-street parking space unless an exemption applies (such as within 1/2 mile walking distance of public transit), a rental minimum of 30 days, and no development impact fees for an ADU under 750 square feet. For an ADU inside an existing permitted structure the code also says fire sprinklers are not required if the primary home has none and a private sewage disposal system needs approval from all appropriate agencies.
- The City's own ADU Guidebook (June 2026) summarizes the standards differently from the code text above: one ADU and one JADU per single-family lot, maximum 1,200 square feet detached, attached 1,200 square feet or 50 percent of the primary home (whichever is less), 16 foot height by right, 800 square feet by right, and a JADU of 500 square feet or less. Because the two City sources disagree, confirm size and height with Planning before drawing.
- Menifee offers a Permit Ready ADU program: eight pre-reviewed, code-compliant plan sets (studios of 306 and 415 square feet up to 3-bedroom plans of 988 and 1,198 square feet) that are free online and in two or more architectural styles. The plans can be flipped to fit the site, a site plan and the application are still required, and the City says using them as provided shortens review.
- Menifee's ADU submittal handout (digital, minimum 24 by 36 inches) is filed in the portal as 'Residential Accessory Dwelling Unit New' and lists the 2025 California codes, the California Wildland-Urban Interface Code and the City Municipal Code, a geotechnical report, a site plan showing septic systems, wells and pools, and NFPA 13-D sprinkler status if the main home is sprinklered. The City's ADU Guidebook says most ADU applications are approved within one to three rounds of review.
- The State HCD's June 30, 2025 letter to Menifee found that Ordinance 2024-384 does not comply with State ADU law in several ways, including leaving out mixed-use zones, limiting unit combinations, requiring separate utility connections, not waiving replacement of uncovered parking and using subjective architectural standards, and asked for a City response by July 29, 2025. No City response was found, so treat City ADU rules as possibly changing.
- ADUs are exempt from several local fees: the Guidebook says State law bars school fees on units under 500 square feet and impact fees on units of 750 square feet or less, and all fees must be paid before the building permit. The City's fee schedules for Planning, Engineering, Fire and Building are linked from its ADU program page.
Is Menifee's ADU ordinance in compliance with California law?
The State Department of Housing and Community Development said no, in part. Its June 30, 2025 letter to Menifee found that Ordinance 2024-384 does not comply with State ADU law in several ways. The letter points to the omission of mixed-use zones, limits on which unit combinations are allowed, a requirement for separate utility connections, a failure to waive replacement of uncovered parking, and subjective architectural standards. HCD asked for a City response by July 29, 2025.
We did not find a City response. That does not mean none exists, only that we could not find one on the City's pages or HCD's. In practice, state law wins where the two conflict, and HCD's letter is a reason to treat any City ADU rule as possibly changing.
For a homeowner the lesson is practical. Do not design to a number on a handout alone. Ask Planning in writing which standard it will apply on your parcel, and ask whether the ordinance has been amended since the letter.
How big and how tall can an ADU be in Menifee?
The City's two sources give different answers, and we will not pick one. The code text on the City's Encode site (Development Code 9.295.020) allows a detached or attached ADU up to 1,500 square feet, a detached height up to 18 feet, 20 feet within a half mile walking distance of a major transit stop and 25 feet for an attached unit. The City's June 2026 ADU Guidebook says 1,200 square feet detached, an attached unit of 1,200 square feet or 50 percent of the main home, whichever is less, a height of 16 feet and 800 square feet by right.
State law sets a floor under both. A city must allow at least an 800 square foot detached unit with side and rear setbacks of no more than four feet, and a height of at least 16 feet (Government Code 66321 and 66314). The code text keeps a four foot setback and one off-street parking space unless an exemption applies, such as a half mile walk to public transit, and a rental term of at least 30 days.
Confirm size and height with Planning before the architect draws a line. The wrong number costs a redraw and a new plan check.
Build an ADU in Menifee: are there pre-approved plans, and how long does the permit take?
Yes, and they are free. The City's Permit Ready ADU program offers eight pre-reviewed, code-compliant plan sets, from studios of 306 and 415 square feet up to three-bedroom plans of 988 and 1,198 square feet, in two or more architectural styles. The plans can be flipped to fit the lot. A site plan and the application are still required, and the City says using the plans as provided shortens review.
The clock is set by law. Under the City's code, an ADU permit is considered ministerially, without discretionary review or a hearing, and the City must approve or deny within 60 days of a completed application when a single-family home already stands on the lot. A denial must come with a written list of defects. The City's Guidebook says most ADU applications clear in one to three rounds of review, and the portal's plan review runs 14 business days for the first round and 10 for each later one.
A new unit is filed in the Menifee Permit Portal as Residential Accessory Dwelling Unit New, on digital sheets at least 24 by 36 inches.
Can you build an ADU on a septic system in Menifee, and what is the Quail Valley moratorium?
Many Menifee lots are not on sewer, particularly in Quail Valley and rural residential areas, and the Guidebook says a new septic system needs Riverside County Environmental Health approval as well as the City's. Eastern Municipal Water District clearances can also apply. Since 2005 the Santa Ana Regional Water Quality Control Board has restricted new septic systems in Quail Valley after failing tanks contaminated Canyon Lake.
Its September 14, 2020 amendment still bars new septic systems in sub-areas 4 and 9 until the home connects to sewer. Sub-areas 1, 2, 3, 5, 6, 7 and 8 can build on septic only if no sewer is available and the system meets an approved Local Agency Management Program or Tier 1 of the State's onsite wastewater policy, with County and City approval. The City says this governs ADUs, additions, new bathrooms and pools there.
The City's ADU handout asks for a site plan that shows septic systems, wells and pools, plus a geotechnical report. We did not see the moratorium map, so ask Building & Safety for your sub-area before you pay for plans.
- Is the lot on sewer, and has Eastern Municipal Water District confirmed it?
- If septic, which Quail Valley sub-area, and is the existing tank in good standing?
- Where will a new sewer or septic line run, and does it cross a drainage course?
Garage conversion ADU in Menifee: parking, sprinklers and what HCD flagged
A garage conversion is the lowest-cost path to a legal unit, and state law gives it protection. Under Government Code 66323 a city must approve an ADU, with or without a junior ADU, converted inside an existing house or accessory structure, with up to 150 square feet added only for entry and exit. Conversions need no new setbacks, and state law bars replacement parking when a garage, carport or uncovered space is converted.
That last point is one HCD raised. Its letter says Menifee's ordinance did not waive replacement of uncovered parking. The City's code does say fire sprinklers are not required for an ADU inside an existing permitted structure when the main home has none, and that a private sewage system needs approval from every agency involved.
The older the garage, the more a records check matters. Menifee's guides check existing structures for permit status, and unpermitted ones can draw separate permits. Ask the City whether the garage has a final inspection on file.
Can you build an ADU on a Menifee hillside, in a fire zone or near a flood area?
Sometimes with extra steps. The State Fire Marshal's recommended 2025 map for Menifee, issued March 24, 2025, has Moderate, High and Very High tiers, and the City's Safety Element says low-lying urban areas are generally Moderate and hillsides Very High. The City's page says Riverside County Fire must adopt the maps by ordinance, and we could not confirm adoption or place any parcel in a zone. A Very High zone home needs 100 feet of defensible space and hardening under the California Wildland-Urban Interface Code, which the City's ADU handout lists. Menifee Fire Department-OFM, run by Riverside County Fire and Cal Fire, reviews fire plans in 14 business days for the first round.
Steep lots add Development Code chapter 9.190, which requires plot plan approval, a slope analysis and biological and cultural reports unless the work stays 50 feet from the top of a steep slope and clear of prominent ridgelines. Parts of Romoland sit in a FEMA 100-year flood zone, and the City says mapped flood zones are incomplete. Some parcels also fall inside airport influence areas for March Air Reserve Base and Perris Valley Airport.
Ask Planning whether the parcel sits in a specific plan. The City lists 17, and they act as customized zoning.
What do ADU fees cover in Menifee, and can you rent the unit or sell it?
Fees are where an ADU budget leaks, and we have no Menifee dollar figure to print. The Guidebook says State law bars school fees on units under 500 square feet and impact fees on units of 750 square feet or less, and that all fees must be paid before the building permit. The City's fee schedules for Planning, Engineering, Fire and Building are linked from its ADU program page, and the City says its planning and impact fees were updated on July 1, 2026. Utility connection charges are a separate matter.
State law does not require the owner to live on the lot for an ADU, and a city may require rentals of 30 days or longer. A junior ADU is capped at 500 square feet inside the house, and owner occupancy applies only if the sanitation is shared. An ADU cannot be sold apart from the house, with narrow exceptions in Government Code 66341 and 66342. If an HOA objects, HCD's handbook cites Civil Code 4751 and 714.3, which void rules that effectively prohibit an ADU on a single-family lot.
We found no City page on HOA rules, so approval by an association is not a City permit step.
ADU photos from Menifee and nearby homes
ADU scenes tied to Menifee and the Inland Empire communities around it, from slabs and trenches to garage conversions and finished cottages. Tap a photo to enlarge it.
What adu construction costs around Menifee
On our ADU construction page, a garage conversion to a studio or one bedroom runs about $100,000 to $200,000, and a new detached unit of 400 to 800 square feet about $200,000 to $400,000. Three independent reads stand behind the ranges, all from Southern California. A UC Berkeley study of households that built or applied for an ADU in 2018 and 2019 found a Los Angeles County median of $100,000. The Terner Center put Los Angeles at $148,000 in 2020. Separately, Remodeling magazine's 2025 Cost vs. Value report lists a Los Angeles ADU job at $178,536, and 39.9 percent comes back at resale. None is a Menifee quote, where the median owner-occupied home is worth $586,100 in the 2024 estimate. Septic work, a utility trench, fire hardening and plan fees each get their own line in a written proposal. The ADU cost guide shows how the ranges are built, and the room addition versus ADU guide helps choose between the two jobs. For other cities' approaches, see ADU construction in Escondido, La Mesa and Los Angeles. A bath inside the unit is on our Menifee bathroom page, an attached project on the Menifee room addition page, windows on the Menifee window page, and the Menifee area page lists every trade we cover in the city.
| What it covers | Typical range |
|---|---|
| Garage conversion to a studio or one bedroom | $100,000 to $200,000 |
| New detached ADU, 400 to 800 sq ft | $200,000 to $400,000 |
| UC Berkeley survey, Los Angeles County median, 2018 and 2019 projects | $100,000 overall. $90,000 garage. $180,000 detached. |
| Terner Center and Berkeley CCI, 2020 | $148,000 Los Angeles estimate. $167,000 statewide average. |
| Remodeling Cost vs. Value 2025, Los Angeles | $178,536 job cost |
| Electrical and plumbing, Angi Los Angeles, January 2026 | Electrical $2,600 to $7,800. plumbing $3,900 to $10,400. |
| City permit and plan check fees | Not priced here |
Menifee ADU questions, answered
How big can an ADU be in Menifee?
The City's papers disagree. The Development Code text allows up to 1,500 square feet and 18 feet of detached height, while the City's June 2026 ADU Guidebook says 1,200 square feet and 16 feet, with 800 square feet by right. State law requires a city to allow at least 800 square feet. Confirm with Planning in writing before drawing.
How do I build an ADU in Menifee?
Start with Planning to confirm size, setbacks and sewer or septic, then draw plans or choose one of the City's eight free Permit Ready plans. File through the Menifee Permit Portal as Residential Accessory Dwelling Unit New, answer plan review comments, pay fees, build and pass inspections. We handle the design, filing and schedule as a licensed general contractor.
How much does it cost to build an ADU in California?
A garage conversion to a studio or one bedroom lands near $100,000 to $200,000 in our sources, and a new detached unit of 400 to 800 square feet near $200,000 to $400,000. Southern California surveys and a 2025 Los Angeles job cost stand behind them, with nothing for Menifee itself, so a site visit and a written proposal set the real figure.
How long does it take to get an ADU permit in Menifee?
By law the City must approve or deny a completed application within 60 days when a single-family home is already on the lot. The City's plan review runs 14 business days for the first round and 10 for later ones, and its Guidebook says most applications clear in one to three rounds. A septic lot adds County review time.
Do I need to provide parking for my ADU?
Usually one space, unless an exemption applies. The City's code requires one off-street space, with exemptions such as a half mile walk to public transit, and state law bars replacement parking when a garage is converted. HCD flagged that the City did not waive replacement of uncovered parking, so ask Planning which version it applies.
What is the difference between an ADU and a JADU?
An ADU is a full second unit, attached or detached, while a junior ADU is a unit of up to 500 square feet built inside the existing single-family house. Menifee's Guidebook allows one of each per single-family lot. A JADU needs an efficiency kitchen and, under state law, owner occupancy only when the sanitation is shared.
Can I build an ADU in Quail Valley?
Possibly, depending on sewer. A 2020 State water board amendment bars new septic systems in Quail Valley sub-areas 4 and 9 until sewer connection, and allows them elsewhere in the area only if no sewer is available and the system meets an approved program. County Environmental Health and the City must approve. Ask Building & Safety for your sub-area.
Do I have to live on the property to rent an ADU?
No for an ADU, since state law does not allow a city to require owner occupancy of one. A city may require rentals of 30 days or longer, and Menifee's code sets a 30 day minimum. A junior ADU is the exception, where owner occupancy applies only if the bathroom is shared with the main house.
Tell us about your Menifee ADU plans
Tell us which neighborhood you are in, whether you are weighing the garage or the back yard, whether the lot is on sewer or septic, and whether you like one of the City's free plans, and we will plan the first visit around that.