ADU Constructionin La Habra, CA
ADU construction in La Habra follows Municipal Code 18.12.150, amended in 2025, and state law: the City decides a complete application ministerially within 60 days, or 30 for a preapproved plan. A detached unit may reach 1,200 square feet, and standards bend to allow 800. Lots near Southern California Edison easements wait for an approved encroachment agreement.
La Habra is a built-out city of single-family lots, which is where ADUs go. The Census Bureau's 2020 to 2024 estimates count 21,225 homes, and 11,069 of them, 52.2 percent, are detached houses, with another 2,013 attached. The City's Housing Element calls the city 99 percent built out and names ADUs and attached townhome infill as its growing housing types. It also says the population jumped from under 5,000 in 1950 to more than 41,350 in 1970, so most lots carry a 1950s to 1970s house with a backyard behind it.
This page covers the utility-corridor hold that is particular to La Habra, the application path and clocks, size and design standards, garage conversions, JADUs and fees, older homes and unpermitted units, and the fire and oil layers. The ordinance text comes from the GoCodebook mirror, which shows Ordinance CC 2025-05, and the City's ADU page backs it, so confirm every rule with Building and Safety. We print no fee amounts. Price ranges and phases are on our ADU construction page.
La Habra Building and Safety rules that apply to ADU construction
Where adu construction permits come from in La Habra: City of La Habra Community and Economic Development Department, Building and Safety Division.
- On July 21, 2025 the La Habra City Council approved amendments to Municipal Code 18.12.150 (ADUs and JADUs), adopted as Ordinance CC 2025-05, according to the City's ADU and Planning pages. The ordinance text decides applications ministerially within 60 days of a complete application (30 days for a pre-approved or previously approved plan), and an application not acted on in 60 days is deemed approved.
- Under Municipal Code 18.12.150, a new detached ADU may be up to 1,200 square feet and a new attached ADU up to 850 square feet (0 to 1 bedroom) or 1,000 square feet (2 or more bedrooms) but not more than 50 percent of the existing home; an ADU within an existing or proposed home has no size limit. Side and rear setbacks are 4 feet, a detached ADU must be 10 feet from other buildings, height follows the zone, and the standards are waived as needed to allow an 800 square foot ADU. This text comes from a third-party code mirror showing the 2025 ordinance.
- La Habra requires one parking space for an ADU with a bedroom (tandem on the driveway allowed), but no space for a studio and no space where the ADU is within one-half mile walk of transit, is part of the existing residence or an accessory structure, has a car share within one block, or is in a historic district. Spaces lost to a garage or carport conversion need not be replaced.
- La Habra's ADU ordinance charges no impact fee on an ADU under 750 square feet, charges larger ADUs impact fees in proportion to the primary home's size, requires utility connections, bars rental under 31 days, bars separate sale except as state law allows, requires a new ADU's street-facing side to show at least three unified architectural features and the same roof style as the home, and limits a JADU to 500 square feet with a deed restriction requiring owner occupancy.
- Per the City's ADU page, a lot with an existing or proposed single-family home may have one ADU and one JADU, a multifamily lot may have attached ADUs up to 25 percent of the existing units (at least one) plus up to two detached ADUs, and the building permit package needs the permit application, plans and an ADU survey. If the lot is within or near a Southern California Edison easement, SCE review is required first, a Preliminary Title Report must be included, and the application is held incomplete until an approved SCE Encroachment Agreement is received.
- The City's ADU page says Building and Safety receives every ADU permit package, routes it to Building, Planning, Engineering and Public Works, and refers projects that need fire review to the Los Angeles County Fire Department. It also accepts County of San Diego pre-approved ADU plans, which cannot be modified and still need Title 24, CalGreen and truss calculations and La Habra-specific information.
- For unpermitted ADUs built before January 1, 2020, La Habra's code bars denial of a permit solely because the unit violates building standards or zoning, limits impact and connection fees on such a unit, and says any notice to correct a violation issued before 2030 must tell the owner that enforcement can be delayed five years if the building official finds it is not needed to protect health and safety.
- Municipal Code 18.24.060 lets the City approve a two-unit housing development or urban lot split in a single-unit zone ministerially, with 4-foot side and rear setbacks, one parking space per unit unless near transit or a car share, and exclusions for sites in a historic district or city landmark, a hazardous waste site, an earthquake fault zone and FEMA flood hazard areas. The City's 2021 SB 9 summary handout also lists high fire severity zones among the exclusions, so confirm the current rule for a hillside parcel.
Does a Southern California Edison easement stop an ADU on a La Habra lot?
It can stall one, which makes this the first question to ask about any lot near a transmission corridor. The City's ADU page says that when a lot is within or near a Southern California Edison easement, SCE review comes first, a Preliminary Title Report must go in with the package, and the application is held incomplete until an approved SCE Encroachment Agreement arrives. A held application does not start the City's 60 day clock.
So the order of work changes. Order the title report, look for the easement on it, and write to SCE before a designer draws a footprint, because the unit may have to sit outside the strip or be redrawn around it. We read no SCE timing, so we make no claim about how long an agreement takes.
Utilities are the second layer. The ordinance requires utility connections for the unit, and the City's pool handout asks owners to check easement issues with Engineering at 562-383-4151, a sensible call for any backyard build. Ask a plumber to camera the existing sewer lateral and an electrician whether the main panel can carry a second dwelling before the design is final.
How do you build an ADU in La Habra, from application to final inspection?
Building and Safety receives every ADU permit package, and the package needs the City's permit application, plans and an ADU survey. The City routes it to Building, Planning, Engineering and Public Works, and refers projects that need fire review to the Los Angeles County Fire Department. Submittals run through the Customer Self Service portal, and staff take 1 to 3 business days to check for completeness.
The ordinance text decides applications ministerially, with no hearing, within 60 days of a complete application, or 30 days for a pre-approved or previously approved plan, and an application not acted on in 60 days is deemed approved. State law adds a clock on the front end: Government Code section 66317, as amended for 2026, has the City tell the applicant within 15 business days whether the application is complete. A denial must come with a full list of defects.
The City said on July 21, 2025 that it approved the amendments to Municipal Code 18.12.150, and the mirror dates Ordinance CC 2025-05 to August 4, 2025. It also accepts County of San Diego pre-approved ADU plans, which cannot be modified and still need Title 24, CalGreen and truss calculations and La Habra-specific information.
How big can an ADU be in La Habra? Square feet, setbacks and street-side design
A new detached ADU may reach 1,200 square feet. A new attached unit is capped at 850 square feet for zero or one bedroom and 1,000 for two or more, and never above 50 percent of the existing home. An ADU built within an existing or proposed home has no size limit. Side and rear setbacks are 4 feet, a detached unit sits 10 feet from other buildings, and height follows the zone.
The ordinance also says its standards are waived as needed to allow an 800 square foot ADU, which tracks the state floor. Government Code section 66321 bars a city from setting a maximum below 850 square feet, or 1,000 if the unit has more than one bedroom, and 800 square feet must still be allowed with 4 foot side and rear setbacks.
Design rules apply on the street side. A new ADU must show at least three unified architectural features and the same roof style as the home on its street-facing side. Multifamily lots follow a different count: attached ADUs up to 25 percent of the existing units, at least one, plus up to two detached. On a lot with a house, one ADU and one JADU is the limit.
Can I convert my La Habra garage to an ADU, and do I need to replace the parking?
Yes, and no replacement is required. La Habra's ordinance says spaces lost to a garage or carport conversion need not be replaced, and Government Code section 66314 says the same for the state. A conversion inside existing space is one of four ADU types the state requires every city to approve.
The ADU itself needs one parking space if it has a bedroom, and tandem on the driveway counts. None is required for a studio, or where the unit is within a half mile walk of transit, is part of the existing residence or an accessory structure, has a car share within one block, or is in a historic district. That list covers most garage conversions.
The questions that matter sit under and around the old garage. Ask for records research on past permits, a look at the slab and footings, a plan for the door opening, a bathroom, a separate water shut-off and an electrical service decision. We read no La Habra handout for garage conversions, so ask whether Building and Safety has a standard detail sheet. The garage conversion permit guide shows the checklist Los Angeles uses, which is a useful comparison and not La Habra's rule.
JADUs, renting, selling and impact fees for a La Habra ADU
A junior ADU is limited to 500 square feet. The ordinance text asks for a deed restriction with owner occupancy, while state law as amended for 2026 requires owner occupancy only where the JADU shares a bathroom with the main house, so ask Planning which rule governs your design. Our ADU versus JADU guide compares the two unit types.
The ordinance bars rental for fewer than 31 days and bars separate sale except as state law allows, which means a qualified low-income buyer through a nonprofit or a city condominium ordinance. We found no La Habra condominium ordinance for ADUs. Impact fees are the other money rule: none for an ADU under 750 square feet, and fees in proportion to the primary home's size above that. Utility connection charges are separate.
Two outside facts help planning. The Housing and Community Development handbook says a newly built detached ADU must carry solar panels under the Energy Code, which conversions do not, and the CalHFA grant of up to $40,000 had run out of funds when the handbook was written. On property tax, the Board of Equalization says a reassessment reaches only the new portion of a property, valued at what it adds in the market.
ADUs behind a 1960s house: unpermitted units, SB 9 lots and what the City allows
Many La Habra lots already hold a converted garage or back room. For an unpermitted ADU built before January 1, 2020, the City's code bars denying a permit solely because the unit violates building or zoning standards, and limits impact and connection fees on such a unit. Any notice to correct a violation issued before 2030 must say enforcement can be delayed five years if the building official finds correction is not needed to protect health and safety.
Housing age sets the checklist. About 76.6 percent of La Habra's homes were built before 1980, and the City's Housing Element says substandard units are spread across the city. Ask the plumber and electrician what the existing house will tolerate, because a second dwelling doubles the load on a 1960s service and a sewer lateral.
SB 9 is the cousin to this page. Municipal Code 18.24.060 lets the City approve a two-unit development or urban lot split in a single-unit zone ministerially, with 4 foot side and rear setbacks and one parking space per unit unless near transit or a car share. Sites in a historic district, hazardous waste site, earthquake fault zone or FEMA flood area are excluded, and the City's 2021 handout also lists high fire severity zones, so confirm the current rule for a hillside parcel.
A Los Angeles County fire code, new fire zones and the old oil field under La Habra ADU lots
La Habra is an Orange County city that adopted the County of Los Angeles Fire Code as its own, under Municipal Code 15.46.010, and contracts with the Los Angeles County Fire Department for fire prevention. For an ADU that matters at the review step: the Fire Department checks improvements to buildings with fire sprinklers and the plan package goes to that department when fire review applies. State law bars an ADU from forcing sprinklers into the main house, and requires them in the ADU only if the main house has them.
A new state map is the second layer. CAL FIRE's March 24, 2025 recommended map lists La Habra with 138 Moderate, 125 High and 250 Very High, in the units of the state's table, and the City posted it for comment from April 21 to July 11, 2025. We did not verify which streets fall in which tier, so check the parcel on the City's fire hazard map page before promising a hillside unit.
Slope and oil are the third. The Westridge and La Habra Hills area was built on the former Coyote oil field, and Municipal Code 18.50 maps an Oil Wells and Drilling overlay zone. Grading follows the Orange County Grading and Excavation Code as the City adopted it, and we found no separate hillside ordinance. MDG Builders, CSLB #1040337, is the general contractor on these jobs, and licensed grading, concrete, framing and plumbing firms build the unit.
ADU photos from La Habra and nearby homes
ADU scenes tied to La Habra and the Orange County and Los Angeles County communities around it, from garage conversions and utility trenches to finished cottages. Tap a photo to enlarge it.
What adu construction costs around La Habra
The ADU construction page sources a garage conversion to a studio or one bedroom at roughly $100,000 to $200,000 and a new detached unit of 400 to 800 square feet at roughly $200,000 to $400,000. Three independent reads stand behind that: a UC Berkeley survey of 2018 and 2019 households that found a $100,000 Los Angeles County median, the Terner Center's 2020 estimate of $148,000 for Los Angeles, and Remodeling magazine's 2025 Cost vs. Value report, whose $178,536 Los Angeles job cost recouped about 39.9 percent at resale. None is a La Habra or Orange County quote. A directory page that lists garage conversions at $73,000 to $133,000 gives no method, so we left it out. Permit, plan check, school and utility charges are separate lines in a written proposal, because the City's fee schedule was too garbled to read with confidence. The ADU cost guide explains what moves the number. For nearby work, compare ADU construction in Fullerton, Whittier, La Mirada and Placentia. A bath inside the unit is on our La Habra bathroom page, an attached addition on the La Habra room addition page, windows for the unit on the La Habra window page, and the La Habra 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 |
La Habra ADU questions, answered
Can I build an ADU in La Habra?
Yes. Municipal Code 18.12.150 allows one ADU and one JADU on a lot with a single-family home, and state law requires approval without a hearing. The City decides a complete application within 60 days. Lots under a Southern California Edison easement wait for an approved encroachment agreement, so check your title report first.
How do you build and permit an ADU in La Habra?
Send Building and Safety the permit application, plans and an ADU survey through the City's online portal. The City routes the package to Building, Planning, Engineering and Public Works, and to the Los Angeles County Fire Department when fire review applies. A complete application is decided within 60 days, or 30 for a preapproved plan.
How big can an ADU be in California?
State law lets a city cap a new detached ADU no lower than 850 square feet, or 1,000 if it has more than one bedroom, and 800 square feet must always be allowed. La Habra's ordinance reaches 1,200 square feet for a detached unit, 850 or 1,000 for an attached one within 50 percent of the house, and 500 for a JADU.
How much does it cost to build an ADU in California?
Budget roughly $100,000 to $200,000 to convert a garage and $200,000 to $400,000 to build a new detached unit of 400 to 800 square feet. Those ranges rest on Los Angeles County data and a 2025 Los Angeles report, since no La Habra survey turned up. A written proposal, with fees as separate lines, sets the real price.
Do I need to provide parking for my ADU?
Usually one space if the unit has a bedroom, and tandem on the driveway counts, but none for a studio or a garage conversion. La Habra also waives parking within a half mile walk of transit, near a car share within one block, in a historic district and when the ADU is inside the home or an accessory structure.
What is the difference between an ADU and a JADU?
A JADU is smaller and lives inside the house, while an ADU can be detached, attached or converted. A JADU is capped at 500 square feet and needs an efficiency kitchen and its own entry. La Habra's text asks for owner occupancy by deed restriction, and state law limits it to JADUs sharing a bathroom.
Can I convert my garage to an ADU?
Yes. A conversion inside existing space is one of four ADU types California requires cities to approve, and La Habra does not make owners replace the lost spaces. Expect a records check, slab and footing review, infill of the garage door opening, a bathroom and a decision on separate electrical service.
Can I sell my ADU separately from the main house?
Generally no. La Habra bars separate sale except as state law allows, and state law allows it only to a qualified buyer through a qualifying nonprofit or under a city condominium ordinance. We found no La Habra condominium ordinance for ADUs, so ask Planning at 562-383-4100 before planning a sale.
How long does it take to get an ADU permit in La Habra?
The City has 60 days to decide a complete application, or 30 for a preapproved plan, and a missed deadline means deemed approval. State law adds 15 business days for a completeness check. Those are legal limits, not an average, and an SCE easement hold can delay the start. We found no official figure for typical elapsed time.
Tell us about your La Habra ADU plans
Tell us which part of La Habra you are in, whether you are weighing the garage or the backyard, and whether the lot sits near power lines, and we will plan the first visit around those answers.