ADU Constructionin Hemet, CA
ADU construction in Hemet follows state law plus HMC 90-321, amended March 10, 2026. A single-family lot may hold up to two detached ADUs, one attached ADU and one junior ADU, four units in all, and the City reviews each ministerially: a complete application not acted on within 60 days is deemed approved. Confirm your lot with the City.
Hemet has the lots for second units and a clear use for them. The Census Bureau's 2024 five-year estimate counts 35,345 housing units, 52.9 percent of them single-family detached, and 37.7 percent of occupied homes are rented. The median year built is 1984, and 21.1 percent of units date from the 1980s, so the typical home is roughly 40 years old. The city also grew around retirees, and the 2019 Housing Element counted 18,690 residents aged 65 or older, which makes a unit for an aging parent an obvious use. The median owner-occupied home is worth $352,200, plus or minus $12,896.
This page covers unit counts, size and height, garage conversions, a question most cities never face about mobile homes, utilities, fire and soil checks, and the clock. Permits start at the City's Building & Safety Division, and its ADU Plan Check Guide predates the 2026 ordinance. The City's code page blocked our tools with an HTTP 403 error, so the ordinance text was read in GoCodebook, a third-party mirror updated October 19, 2026. Treat every number as a lead for the City to confirm. Cost ranges and phases are on our ADU construction page.
City of Hemet rules that apply to ADU construction
Where adu construction permits come from in Hemet: City of Hemet Community Development Department, Building & Safety Division.
- Hemet's ADU ordinance (HMC 90-321, last amended by Ord. No. 2072 on March 10, 2026) sends ADU and JADU applications to the building department for ministerial plan check with no discretionary review or public hearing. The City must decide completeness within 15 business days and an application not acted on within 60 days of a complete submission is deemed approved unless a new home is being permitted on the same lot. ADUs cannot be short-term rentals (terms must exceed 30 days) and cannot be occupied before the primary dwelling is approved for occupancy (text read in GoCodebook's verbatim copy of the Hemet Municipal Code, a third-party mirror updated 2026-10-19, because the City's own code page at hemetca.gov/104/Municipal-Code returned HTTP 403).
- Unit counts under HMC 90-321: a lot with a single-family home may have up to two detached ADUs, one attached ADU and one JADU, with no more than four units in total on a single-family lot; a lot with an existing multifamily building may have up to four detached ADUs (not more than the number of existing units) plus attached or converted ADUs up to 25 percent of the existing units; a parcel from an SB 9 lot split is limited to two units including ADUs and JADUs (text read in GoCodebook's verbatim copy of the Hemet Municipal Code, a third-party mirror updated 2026-10-19, because the City's own code page at hemetca.gov/104/Municipal-Code returned HTTP 403).
- Size limits under HMC 90-321: detached and attached ADUs may be 850 square feet for a studio or one bedroom and 1,000 square feet for two or more bedrooms (800 square feet for a detached ADU using the simplified standards), an attached ADU that adds more than 150 square feet to the home may not exceed 50 percent of the existing home's floor area, and a JADU must be 150 to 500 square feet inside the existing single-family home (text read in GoCodebook's verbatim copy of the Hemet Municipal Code, a third-party mirror updated 2026-10-19, because the City's own code page at hemetca.gov/104/Municipal-Code returned HTTP 403).
- Setbacks and height under HMC 90-321: four feet from side and rear lot lines for a new ADU and none for a conversion of an existing structure; detached one-story ADUs up to 16 feet (18 feet near major transit or next to a multi-story multifamily building); two-story ADUs over a garage up to 25 feet with 10 foot side and rear setbacks next to single-family lots; two extra feet allowed to match the home's roof pitch (text read in GoCodebook's verbatim copy of the Hemet Municipal Code, a third-party mirror updated 2026-10-19, because the City's own code page at hemetca.gov/104/Municipal-Code returned HTTP 403).
- Parking under HMC 90-321: no replacement spaces are required when a garage or carport is demolished or converted for an ADU, no parking is required for most ADUs and JADUs, and a detached ADU may be asked for one space per ADU or per bedroom, whichever is less, which can be tandem on the driveway (text read in GoCodebook's verbatim copy of the Hemet Municipal Code, a third-party mirror updated 2026-10-19, because the City's own code page at hemetca.gov/104/Municipal-Code returned HTTP 403).
- Fees and utilities under HMC 90-321: no impact fee for an ADU or JADU under 750 square feet, school fees waived at 500 square feet or less, larger ADUs charged in proportion to the main home's size, fire sprinklers required in an ADU only if the primary residence has them, a separate address may be required, and a JADU may not be metered separately (text read in GoCodebook's verbatim copy of the Hemet Municipal Code, a third-party mirror updated 2026-10-19, because the City's own code page at hemetca.gov/104/Municipal-Code returned HTTP 403).
- The City's ADU Plan Check Guide says to get a new ADU address before plan check, that Southern California Edison and SoCalGas will not set an additional meter on an existing billing address, that water and sewer main upsizing should be checked with Water Resources at (951) 765-3712 before plans are final, that a panel load calculation or sub-panel single-line diagram is needed, and that Title 24 forms, window U-factor and SHGC, a 3:12 minimum roof pitch and smoke and carbon monoxide alarms are required. The guide is older than the March 2026 ordinance and still asks for five paper sets and a conditional use permit for non-conforming ADUs, so the ordinance and the portal rules control.
Sources for these rules
Can you build an ADU on a Hemet lot, and how many? The unit counts in HMC 90-321
Hemet's ADU ordinance, HMC 90-321, was last amended by Ordinance No. 2072 on March 10, 2026. A lot with a single-family home may have up to two detached ADUs, one attached ADU and one junior ADU, with no more than four units in total. A lot with an existing multifamily building may have up to four detached ADUs, never more than the number of existing units, plus attached or converted ADUs up to 25 percent of the existing units. A parcel from an SB 9 lot split is limited to two units including ADUs and JADUs.
Applications go to the building department for ministerial plan check, with no discretionary review or public hearing. ADUs cannot be short-term rentals, so rental terms must exceed 30 days, and no ADU can be occupied before the main dwelling is approved for occupancy. The state sets the floor under all of this: the HCD ADU handbook lists the ADU types a city must approve, and Government Code section 66317 makes approval ministerial.
How big and how tall can an ADU be in Hemet? Sizes, setbacks and a unit over the garage
Detached and attached ADUs may reach 850 square feet for a studio or one bedroom and 1,000 square feet for two or more bedrooms, or 800 square feet for a detached ADU built to the simplified standards. An attached ADU that adds more than 150 square feet to the home cannot exceed 50 percent of the existing floor area, and a JADU must measure 150 to 500 square feet inside the existing single-family home.
A new ADU sits four feet from side and rear lot lines, and a conversion of an existing structure needs no setback. Detached one-story units top out at 16 feet, or 18 feet near major transit or beside a multi-story multifamily building. A two-story unit over a garage may reach 25 feet but needs 10-foot side and rear setbacks next to single-family lots, and two extra feet are allowed to match the home's roof pitch.
Style counts too. HMC 90-321(c)(10) requires a new ADU to be architecturally compatible with the main house in style, materials and primary color, so the plan sheet should name the stucco, roof and paint you are matching.
Can you convert a garage into an ADU in Hemet? No replacement parking, but an address comes first
Yes. Hemet requires no replacement spaces when a garage or carport is demolished or converted for an ADU, and no parking at all for most ADUs and JADUs. A detached ADU may be asked for one space per ADU or per bedroom, whichever is less, and that space can be tandem on the driveway. A conversion of an existing structure also needs no new setback, which is why the garage is often the cheapest place to start.
The City's guide says to obtain a new ADU address before plan check, because Southern California Edison and SoCalGas will not set an additional meter on an existing billing address. Sprinklers are required in the ADU only if the primary residence has them. For a 1970s garage the real work is below and behind the door: infilling the opening, adding insulation and glazing that meet Title 24, a bathroom and a kitchen, and a panel that can carry the new load.
The garage slab matters as well. The Public Safety Element says shrink-swell soils are likely to affect building slabs in Hemet, so ask the designer whether the old slab is sound enough to keep or should be replaced.
Can a mobile home or manufactured home be an ADU in Hemet?
State law counts a manufactured home as an ADU, which is a fair question in a city where 8,257 homes, 23.4 percent, are mobile homes. Hemet's zoning adds limits. A mobile home may be lived in only inside a mobile home park, an approved TR-20 independent mobile home subdivision or a travel trailer park (HMC 90-653), and the code bars installing a manufactured home on a single-family lot if more than ten years passed between manufacture and the permit application, unless it is converting from a pier foundation to a permanent one. We could not confirm how the City applies the ten-year rule to an ADU, so ask Planning before you buy a used unit.
Bulletin 109, the City's set-up packet for a mobile home in a rental park, shows how the City looks at a coach. It asks for a permit application, a plot plan signed by the park owner and Planning, the manufacturer's stamped installation instructions, a tie-down system installed at the same time and a school fee letter. It lists 3 feet to a lot line, 10 feet to a permanent building, 10 feet side to side and 75 percent maximum lot coverage. The packet covers park lots, not ADUs, so use it only as a preview of what gets checked.
Which utilities serve a Hemet ADU, and what comes first?
Power and gas come from Southern California Edison and SoCalGas, while water and sewer come from the City. The ADU Plan Check Guide says to check water and sewer main upsizing with Water Resources at (951) 765-3712 before plans are final, and that a panel load calculation or a sub-panel single-line diagram is needed. It also lists Title 24 forms, window U-factor and SHGC, a 3:12 minimum roof pitch and smoke and carbon monoxide alarms. The guide cites the 2022 codes, and we found no Hemet adoption of the 2025 cycle, so ask which edition applies.
A JADU may not be metered separately, and an ADU that shares the home's service needs a clear plan for who pays which bill. Edison's refusal to add a meter at an existing address is why the address request leads the schedule, and a trench for new sewer or water lines is the line item most likely to surprise a budget.
The guide is older than the March 2026 ordinance. It still asks for five paper sets and says a conditional use permit may be required for a non-conforming ADU, but HMC 90-321 makes ADUs ministerial and the Plan Review page sends every project online, so the ordinance and the portal control.
Fire zones, flood and shrink-swell soil: what the lot itself can stop in Hemet
The Public Safety Element says several Very High fire zones lie in the southern half of the City, with about 1,500 parcels in one, and the Four Seasons neighborhood and Simpson Park are named. CAL FIRE's 2025 maps are described on the City's page as proposed, and we did not open them to see which parcels change, so ask Fire Prevention about your parcel. The interface rules in HMC 14-416 to 14-421 require existing development to comply immediately with the landscaping and perimeter protection section, and a unit inside a mapped zone should expect Class A roofing and noncombustible patio covers.
Soil is the second check. Shrink-swell soils occur throughout Hemet, and soil testing is required with plans for new construction, so ask whether an ADU slab counts. Flooding is worst in the southern parts of the City, where rain can pond for hours, and the Hemet and San Jacinto basins can subside. The City's flood rules use FEMA maps dated 1990 and count work costing 50 percent or more of a structure's value as substantial improvement.
How long does an ADU permit take in Hemet, and which fees apply?
The City must decide whether an application is complete within 15 business days, and one not acted on within 60 days of a complete submission is deemed approved, unless a new home is being permitted on the same lot. Building & Safety is at City Hall, 445 E Florida Avenue, while Fire Prevention works from 510 E Florida Avenue, and some older handouts mix the two. Every new application now goes through the Tyler portal, and the Plan Review page says no permit is issued until every department has signed the plans, outside releases from the Health Department, the school fee receipt and the TUMF receipt are in, and fees are paid.
On fees, HMC 90-321 sets no impact fee for an ADU or JADU under 750 square feet, waives school fees at 500 square feet or less and charges larger ADUs in proportion to the main home's size. The City's schedule lists ADU permit lines as multi-column rows that we could not read as single amounts, so we print no dollar figure.
On an ADU, MDG Builders acts as general contractor, CSLB #1040337: we organize the plans and engineering, file in the portal and hire licensed subcontractors for concrete, framing, plumbing and electrical. Ask to see each subcontractor's license and proof of insurance before the trade arrives.
ADU photos from Hemet and nearby homes
ADU scenes tied to Hemet and the Inland Empire communities around it, from garage conversions and slabs to finished cottages. Tap a photo to enlarge it.
What adu construction costs around Hemet
The ADU construction page puts a garage conversion to a studio or one bedroom at about $100,000 to $200,000 and a new detached unit of 400 to 800 square feet at about $200,000 to $400,000. Three outside sources back those ranges. Berkeley researchers surveyed owners who built or applied for an ADU in 2018 and 2019 and found a Los Angeles County median of $100,000, the Terner Center estimated $148,000 for Los Angeles in 2020, and Remodeling magazine's 2025 Cost vs. Value study lists $178,536 for a Los Angeles ADU, with 39.9 percent returned at resale. None is a Hemet quote, and Riverside County costs may differ. With a median owner-occupied value of $352,200 in Hemet, plus or minus $12,896, a detached unit can cost more than half of what the main house is worth, so the garage route deserves a hard look. A written proposal would show permit, plan check, utility, school and TUMF charges as separate lines. The ADU cost guide shows how the ranges were built, the ADU versus JADU guide compares the two unit types, and the room addition versus ADU guide weighs a separate unit against more rooms in the house. For ADUs nearby see Menifee, Moreno Valley, Riverside and Los Angeles. A bath inside the unit is on the Hemet bathroom page, a larger attached project on the Hemet room addition page, glass on the Hemet window page, and the Hemet 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 |
Hemet ADU questions, answered
How do I build an ADU in Hemet?
Start with the City's Building & Safety Division and the ADU rules in HMC 90-321. Get a new address, check utilities, then submit plans through the Tyler portal. The City reviews ministerially and must rule on completeness within 15 business days. An application not acted on within 60 days of a complete submission is deemed approved.
How big can an ADU be in Hemet?
Up to 850 square feet for a studio or one bedroom and 1,000 square feet for two or more bedrooms, or 800 square feet for a detached ADU using the simplified standards. A junior ADU runs 150 to 500 square feet inside the home. Detached one-story units can reach 16 feet, and two-story units over a garage 25 feet.
How much does it cost to build an ADU in California?
Budget about $100,000 to $200,000 for turning a garage into a studio or one-bedroom, and $200,000 to $400,000 for a ground-up detached ADU sized 400 to 800 square feet. Those ranges rest on Berkeley, Terner Center and Cost vs. Value data for Los Angeles, not on a Hemet bid, and utility, school and permit charges come on top.
Do I need to provide parking for my ADU?
Usually not. Hemet requires no replacement spaces when a garage or carport is converted, and no parking for most ADUs and JADUs. A detached ADU may be asked for one space per ADU or per bedroom, whichever is less, and it can be tandem on the driveway. Ask Planning whether your lot is an exception.
What is the difference between an ADU and a JADU?
A junior ADU is smaller, 150 to 500 square feet, and must sit inside the existing single-family home, while an ADU can be detached, attached or converted and run up to 850 or 1,000 square feet. In Hemet a JADU may not be metered separately, and a lot can hold one JADU among its four units.
Do I have to live on the property to build or rent an ADU?
State law does not let a city require owner occupancy for an ADU, though a city may require rentals of 30 days or longer, and Hemet does. A junior ADU needs an owner on site only when it shares a bathroom with the home. Confirm the current Hemet wording with Planning before you rent.
How long does it take to get an ADU permit?
The City must decide completeness within 15 business days, and a complete application not acted on within 60 days is deemed approved. Add time for plan corrections, outside releases and fee payment before the permit issues. Construction then runs on top of that, and a conversion is usually faster than a new detached unit.
Can I convert my garage into an ADU in Hemet?
Yes. Hemet requires no replacement parking when a garage is converted and no setback for converting an existing structure. Get an ADU address first, plan for a bathroom, a kitchen and a panel that can carry the load, and ask the designer whether the garage slab should stay. Sprinklers are needed only if the main home has them.
Can a mobile home be an ADU in Hemet?
State law counts manufactured homes as ADUs, but Hemet's code bars placing a manufactured home on a single-family lot if more than ten years passed between manufacture and the permit application. We could not confirm how that rule applies to ADUs, so ask Planning before you buy a used unit.
Can my HOA stop me from building an ADU?
Not outright. HCD's handbook says state law voids covenants that effectively prohibit or unreasonably restrict an ADU or JADU on a single-family lot, and 2025's AB 130 bars HOA rules that add fees or financial requirements. An association can still ask for reasonable design review, so read your covenants and write to the board early.
Tell us about your Hemet ADU
Tell us which part of Hemet the lot is in, whether you are weighing the garage or the yard, how old the main house is and whether the lot sits near open hills, and we will plan the first visit around the unit counts and the utility questions.