Whittier ADU rules and requirements

Yes, you can build an ADU on any Whittier lot that has or will have a home. A new backyard unit on a single-family lot can be 1,200 sq ft, or 1,500 sq ft on a lot of 20,000 sq ft or more. Most lots need no parking. Planning charges $1,076 to review the unit, with building fees set from the construction value on top, and the city has 60 days to decide once your application is complete.

Backyard unit: Up to 1,200 sq ft, or 1,500 on lots of 20,000 sq ft or more⁴⁸
Parking: None near a bus stop, for a studio, or for a conversion⁴⁸¹⁰
City permit fees: $1,076 planning review, plus building fees set by construction value⁵⁶
Decision: Within 60 days, or 30 days with a pre-approved plan⁴¹²

Figures read from the city's own documents, last checked 20 September 2026. Each number links to its source.

Who to call: Whittier Planning Division, Community Development Department, 562-567-9320. City Hall, 13230 Penn Street, Whittier, CA 90602. Planning counter 7:30 a.m. to 4 p.m. Monday to Thursday, 8 a.m. to 4 p.m. Friday. planning@cityofwhittier.org.³

Local rules in effect. Whittier has its own ADU ordinance, last amended on 23 September 2025, and it tracks the state rules. The city's rules are in Municipal Code section 18.10.020(I). Where they and state law differ, the city applies whichever is more generous to you.⁴

The rules at a glance

"City rule" means Whittier set the figure. "State rule" means the city applies the state minimum, which no city can go below.

ADU rules in Whittier
Backyard unit, max size City rule	1,200 sq ft for a new detached unit on a single-family lot. On a lot of 20,000 sq ft or more it can be 1,500 sq ft. Converting a garage or other existing building: up to 1,200 sq ft, or the building's current footprint plus 150 sq ft for an entry if it is already over 1,200. On a lot with apartments, a new detached unit is capped at 800 sq ft. Whatever else applies, an 800 sq ft unit with 4 ft setbacks cannot be refused.⁴⁸¹⁴
Attached unit, max size City rule	850 sq ft for a studio or one-bedroom, 1,000 sq ft for two or more bedrooms, or half the floor area of the existing house, whichever is larger.⁴⁸
Junior unit, max size State rule	500 sq ft, inside the existing house or its attached garage, with its own outside door and a small kitchen. The city records a deed restriction before it signs off.⁴¹³
Height State rule	16 ft for a detached unit, one story. 18 ft if the lot is within a half-mile walk of a major transit stop or a high-quality transit corridor, plus 2 ft to match the roof pitch of the house. A unit above a garage is allowed if the stairs are inside or hidden from the street. An attached unit can go to 25 ft or the zone's limit, whichever is lower, and can be two stories if the house is.⁴⁸
Setbacks City rule	Four feet from the side and rear property lines for anything new, 10 ft from a side street, and the normal front setback for your zone. Keep 5 ft between the unit and the house, and 5 ft from the line for any wall with a door or window. The city wants the unit at the back of the lot first. A garage you convert, or rebuild in the same spot and size, keeps its current setbacks.⁴⁸¹
Parking City rule	One space, and tandem in the driveway counts. You need none if the lot is within a half-mile of a bus stop (most of the city, per the city's map), the unit is a studio, the lot is in a historic district, you are converting existing space, permit parking on your street is not offered to the unit, or a car-share vehicle is within a block. Converting or demolishing a garage never requires replacing its parking. A space must be 10 by 20 ft, not compact, and no new curb cut is allowed.⁴⁸¹⁰
Lot coverage and open space State rule	The unit normally has to fit the zone's lot coverage and floor-area limits, but those limits cannot be used to block an 800 sq ft unit that meets the 4 ft setbacks and the height limit. The 1,200 and 1,500 sq ft figures only work if the lot has room under the zone's other rules.⁴¹⁴
Do you have to live there State rule	No, not for an ADU. For a junior unit that shares a bathroom with the house, the owner must live in either the house or the junior unit. Since 1 January 2026 a junior unit with its own bathroom has no owner-occupancy rule, even though the city's code text still reads the older way.⁴¹³
Renting it out City rule	Tenants must stay 31 days or longer. Nightly and weekly rentals of an ADU or junior unit are not allowed, and neither unit can be sold separately from the house.⁴

Whittier ADU permit fees

City permit fees
Planning review of an ADU (Development Review, Level A)	$1,076 City Fee Schedule, Resolution 2026-37, Planning item 104; Planning Division Service Fees sheet⁵⁶
Building permit, plan check and issuance	Set from the construction value. The permit fee comes from the valuation table in the fee schedule, plan review is 65% of the permit fee, mechanical, electrical and plumbing review is 10% of plan check, issuance is $31 and the technology fee is $45. The state green building fee adds $1 per $25,000 of value. Ask Building and Safety for the valuation they will use before you budget; the city does not publish an ADU example. City Fee Schedule, Resolution 2026-37, Building items 26, 27, 38, 39 and 41⁵
Fire flow test (required for every ADU before Planning will take the application)	$547 City Fee Schedule, Resolution 2026-37, Public Works item 161⁵³
Sewer lateral video review	$280, plus any repairs the video shows, at your cost City Fee Schedule, Resolution 2026-37, Public Works item 172; sewer lateral form in the ADU application packet (Ordinance 3059)⁵⁸
New address for the unit	$120 (one hour at the hourly rate) City Fee Schedule, Resolution 2026-37, Building item 22; Preapproved ADU Plans page, Step 4⁵¹
City development impact fees (library, public facilities, aquatics, parks)	Nothing if the unit is 750 sq ft or under. Above that, a share of the city's per-house rates, which total $7,693 for a detached dwelling under the 2010 schedule, in proportion to the unit's size against the house. The city publishes no ADU line, so ask Planning for the figure before you choose between 750 and 800 sq ft. Development Impact Fee Schedule, Resolution 8290 Exhibit A; Gov. Code ADU article⁷¹¹
School district fee	Charged only when the unit is over 500 sq ft; the rate depends on which school district your lot is in ADU and JADU Checklist, Building and Safety Requirements⁹
Certificate of Appropriateness (historic districts and landmark properties only)	$1,218 City Fee Schedule, Resolution 2026-37, Planning item 113⁵

How long it takes

Plan on the fire flow test and sewer video before you can even file, then the full 60 days plus one round of corrections; a resubmittal on a pre-approved plan takes about 5 days.¹²³⁴¹

Completeness check: 15 business days for the city to tell you whether your application is complete under state law. The city says online submittals are assigned to a planner within 7 to 14 working days.
Decision: 60 days after a complete application to approve or deny, or the unit is approved by default
Pre-approved plans: About 5 business days of plan check, and a decision within 30 days by city code

Does an ADU fit your lot in Whittier?

The rules above are the city's. Whether they work on your lot depends on the lot. Type your address and we tell you yes, no, or yes with conditions, then connect you with one licensed builder who works in Whittier. Free, and nobody calls unless you ask.

Check my address

Things to know before you build in Whittier

Two things come before Planning will take your application: a fire flow test through Engineering ($547) and a video of your sewer lateral from the house to the city main ($280 to review). If the video shows cracks or sags, you repair the line at your cost before the permit issues.
The 1,200 and 1,500 sq ft figures are ceilings, not guarantees. Only an 800 sq ft unit with 4 ft setbacks is protected from the zone's lot coverage and floor-area limits, so check with Planning before you design bigger.
A studio needs no parking space anywhere in the city, and any unit within a half-mile of a bus stop needs none either. Look at the city's parking exemption map before you give up driveway space.
If you convert or demolish the garage, the driveway must still hold a car, or you pay to remove it, close the curb cut and restore the curb and parkway. No new curb cuts are allowed for an ADU.
Size thresholds worth knowing: school fees start above 500 sq ft, and city impact fees start above 750 sq ft. A 750 sq ft unit avoids the impact fees; the city's own pre-approved 757 and 800 sq ft plans do not.

Overlays that change the answer

Historic districts and landmark properties. Chapter 18.84 applies. A Certificate of Appropriateness ($1,218) may be needed, the unit cannot harm the historic character of the house or a contributing garage, and no parking is required.⁴⁸⁵
High Fire Severity Zone. Instead of the city's fire flow form, you need plans approved by the Los Angeles County Fire Department. Check the city's fire zone map first.⁹³
Areas with insufficient water or sewer service. New ADUs are not allowed where the director's map shows the water or sewer system cannot serve them. Ask Planning whether your address is on the map.⁴

Pre-approved ADU plans in Whittier

Available Four free plans, all one-story detached units: a 311 sq ft studio, a 495 sq ft one-bedroom, a 757 sq ft two-bedroom with one bath, and an 800 sq ft two-bedroom with two baths, each in Craftsman, Spanish or Traditional styling. The plans cannot be changed at all. Your lot must be zoned R-E, H-R or R-1 with a house on it, and the unit must sit 5 ft from any other building. You sign a hold-harmless agreement, get a fire flow test and a sewer video first, and file through the online permit portal. The city checks completeness in 1 to 2 business days and plan check takes about 5 business days; the code requires a decision within 30 days.¹²⁴

Questions people ask

How big can an ADU be in Whittier?

A new backyard unit on a single-family lot can be 1,200 sq ft, or 1,500 sq ft if the lot is 20,000 sq ft or more. An attached unit can be 850 sq ft (studio or one bedroom), 1,000 sq ft (two or more bedrooms), or half the house, whichever is larger. A junior unit inside the house can be 500 sq ft.

Do I need parking for an ADU in Whittier?

Usually not. A studio, a unit within a half-mile of a bus stop, a unit in a historic district, or a converted garage or room needs no parking. Otherwise one space, and tandem in the driveway is fine.

How much are ADU permit fees in Whittier?

Planning charges $1,076 to review the unit. Building permit and plan check fees are set from the construction value, plus a $547 fire flow test, $280 for the sewer video review and $120 for a new address. City impact fees apply only above 750 sq ft and school fees only above 500 sq ft.

How long does an ADU permit take in Whittier?

The city has 15 business days to tell you whether your application is complete and 60 days after that to decide, or the unit is approved by default. A pre-approved plan gets a decision within 30 days, with plan check taking about 5 business days.

Does Whittier have pre-approved ADU plans?

Yes. Four free one-story detached plans, from a 311 sq ft studio to an 800 sq ft two-bedroom, each in Craftsman, Spanish or Traditional styling. They cannot be modified, and you sign a hold-harmless agreement to use them.

Can I convert my garage into an ADU in Whittier?

Yes. It keeps its current setbacks, you do not have to replace the parking, and it can grow by 150 sq ft for an entry. The driveway must still hold a car or be removed and the curb restored at your cost.

What changed

23 June 2026 City fee schedule re-adopted as Resolution 2026-37 (rescinding Resolution 2025-40). Planning review of an ADU stays at $1,076.
1 January 2026 AB 1154 took effect: a junior unit with its own bathroom no longer requires the owner to live on the property.
1 January 2026 SB 543 took effect: a 15-business-day completeness check and 60-day deemed approval under Gov. Code 66317.
23 September 2025 Ordinance 3167 amended the city's ADU section, Municipal Code 18.10.020(I).
26 August 2025 City fee schedule amended (Resolution 2025-40).
1 January 2025 AB 1332 deadline for cities to offer pre-approved ADU plans. Whittier's four free plans in three styles are live on the city site as of September 2026.
1 January 2025 AB 2533 took effect: an ADU built without permits before 2020 can be legalized without penalties or impact fees unless it is a health or safety hazard. The city code now says the same.
12 November 2024 Ordinance 3159 amended the ADU section.

Sources

Preapproved ADU Plans, City of Whittier Community Development. Accessed 20 September 2026.
Pre-Approved ADU Hold Harmless Statement, City of Whittier Community Development. Accessed 20 September 2026.
Planning Services page (ADU application process, counter hours, fire flow requirement), City of Whittier Community Development. Accessed 20 September 2026.
Whittier Municipal Code 18.10.020(I), Accessory Dwelling Units (Chapter 18.10, Residential Zones Generally), City of Whittier, via Municode. Accessed 20 September 2026.
City Fee Schedule, Resolution No. 2026-37, adopted 23 June 2026, City of Whittier. Accessed 20 September 2026.
Planning Division Service Fees, City of Whittier Planning Division. Accessed 20 September 2026.
Development Impact Fee Schedule, Resolution No. 8290, City of Whittier. Accessed 20 September 2026.
Accessory Dwelling Unit / Junior ADU Application and ADU Handout, City of Whittier Planning Division. Accessed 20 September 2026.
Accessory Dwelling Units (ADU/JADU) Checklist, City of Whittier Community Development. Accessed 20 September 2026.
Accessory Dwelling Parking Exemption map (residential properties within a half-mile of transit stops), City of Whittier. Accessed 20 September 2026.
Government Code sections 66310 to 66342, ADU law (link opens at section 66314), State of California. Accessed 20 September 2026.
Government Code section 66317, permit timelines (SB 543), State of California. Accessed 20 September 2026.
Government Code section 66333, junior accessory dwelling units (as amended by AB 1154), State of California. Accessed 20 September 2026.
Government Code section 66323, units that must be approved (the 800 sq ft unit), State of California. Accessed 20 September 2026.

Nearby

Los Angeles County

Educational guidance drawn from the city's published rules, not a permit determination or a quote. Rules change; the date at the top is when these were last checked. Spotted a wrong figure? Tell us.