What are Pasadena's ADU rules?

How big an ADU can I build in Pasadena?

Up to 800 sq ft on any single-family lot, and up to 1,200 sq ft if the unit fits the zone's normal standards. Section 17.50.275 of Pasadena's code sorts ADUs into two tracks ².

Exemption ADUs are the units state law makes the city approve: a detached new unit of up to 800 sq ft, a garage or accessory-structure conversion with no size limit, or a conversion inside the house, each of which can be paired with a junior ADU of up to 500 sq ft ².

Non-exemption ADUs use Pasadena's larger limits: 1,200 sq ft detached, or 850 sq ft for a studio or one-bedroom and 1,000 sq ft for more bedrooms when attached ², but they must meet the zone's encroachment plane, floor area, lot coverage and setback rules ³. Every ADU must be at least 150 sq ft ². In the Hillside Overlay Districts a detached new unit is capped at 1,000 sq ft ⁵.

One caution as of October 2026: HCD, the state housing department, told Pasadena in February 2025 that the ordinance fails to comply with state law, including by allowing only one exemption ADU per lot when state law lets an owner combine a converted ADU, a detached new ADU and a junior ADU ⁶. The ordinance says state law prevails where they conflict ², so if you want more than one unit, ask Planning in writing.

How tall can it be, and how close to the property line?

Four feet from the side and rear lines for any new unit, and 18 feet tall for most detached units ².

• Setbacks: 4 feet at the side and rear for new construction; a straight conversion needs no setback beyond fire safety ². A non-exemption ADU must also respect the zone's front yard; an exemption ADU does not ², and HCD flagged that clause because state law does not let a front setback block an 800 sq ft unit ⁶.
• Detached height: 18 feet and two stories by default, dropping to 16 feet in a Hillside Overlay District, in a landmark or historic district when the unit is visible from the street, or for an exemption ADU in the front setback. Within a half-mile walk of a major transit stop those sites get 18 feet plus two more to match the house's roof pitch ².
• Attached height: 25 feet and two stories, or the zone's limit if lower ².

Our LA height and setback guides cover the state baseline.

Do I have to add a parking space?

Often not. Pasadena asks for one space per unit or per bedroom, whichever is less, covered, uncovered or tandem on the driveway ⁷. No space is required if the lot is within a half-mile walk of a public transit stop, the ADU is inside the existing space of the house or an accessory structure including a garage, the property is in a historic district, or a car-share pick-up point is within one block ⁷.

If you convert or demolish the garage that held the house's required parking, you do not have to replace it, and the ADU shares the house's driveway ⁷. HCD's letter adds that the city cannot impose any parking requirement on an exemption ADU ⁶.

What does Pasadena charge in fees, and where are the breaks?

Pasadena's own survey put its plan check and permit fees at about $14,300 for an 800 sq ft ADU, $16,900 at 1,000 sq ft and $22,100 at 1,200 sq ft, the highest of 14 cities compared ⁸. The council then cut several fees, effective May 6, 2025, with the impact fee and construction tax cuts following on July 17, 2025 ⁴. As of October 2026, for an ADU on a single-family lot ⁴:

• 900 sq ft or smaller, no housing agreement: exempt from the Residential Impact Fee; 25 percent off the Construction Tax, General Plan Maintenance Fee and Technology Fee; C&D deposit cut to $1,000.
• Any size with a Housing Agreement, or built from a city Standard Plan: plan check fees cut 50 percent; exempt from the Residential Impact Fee, Construction Tax, General Plan Maintenance Fee and Technology Fee; C&D deposit $1,000.
• Everything else: C&D deposit $1,000.

An ADU over 900 sq ft with no agreement pays a Residential Impact Fee in proportion to the size of the main house ⁴. That 900 sq ft line is more generous than the state's 750 sq ft exemption ⁹, and staff said units of 900 sq ft or less are nearly 90 percent of the ADUs built in Pasadena ⁸.

A Housing Agreement is optional, must be signed before the permit issues, and commits the unit for at least seven years to a family member, a city rental-assistance tenant, or a household at or below 120 percent of area median income ⁴. Property tax is set by the LA County Assessor, not the city ⁴; see our property tax guide.

My house is in a landmark or historic district. What changes?

You can still build, but a city-standard unit has to hide from the street unless that is impossible. The council had formally designated 27 landmark districts between 1989 and mid-2019, when it added Arden Road as LD-28 ¹⁰. The code says a non-exemption ADU in an individually designated historic property or a landmark or historic district shall not be visible from the public right-of-way, unless that requirement prevents the creation of the unit ². Three other things follow:

• Height: a detached unit visible from the street is capped at 16 feet instead of 18 ².
• Parking: none required ⁷.
• Design review: a Certificate of Appropriateness, evaluated under the city's Design Guidelines for Historic Districts and the Secretary of the Interior's Standards ¹¹.

HCD's handbook says ADUs are allowed in historic districts and a city may impose objective standards to protect listed property, but that an ADU created under state Section 66323, the 800 sq ft exemption unit, is not subject to local design standards beyond that section ⁹. So the visibility rule clearly binds the larger unit; for an 800 sq ft exemption unit on a visible site, ask DHPQuestions@cityofpasadena.net, the city's contact for historic-district ADUs ¹.

Can I use the city's pre-approved plans or its ADU loan?

Yes to both, with conditions. The city's earlier Standard Plans expired on December 31, 2025 when the 2025 California Building Code took effect, and can now be used only on properties red-tagged by the Eaton Fire ¹². One new plan arrived in August 2026: Prototype A, a 374 sq ft studio, free, usable on most single-family lots ¹². It earns the 50 percent plan check discount and the fee exemptions above ⁴, but no modification is allowed, however minor, and the lot must not be on a slope, hillside or expansive soil ¹².

The Pasadena Second Unit ADU Program lends up to $250,000 at 1 percent simple interest with no payments for three years, with a city-assigned construction manager, in return for renting to a Pasadena Housing Choice Voucher tenant ¹³.

The rental rules apply either way: any ADU or junior ADU created since January 1, 2017 must be rented for longer than 30 days, and the unit cannot be sold separately from the house unless a qualified nonprofit built it ²; see our condo guide.

What should I check first for a Pasadena address?

Work through the city's own process diagram, which puts the checks in this order ¹⁴:

1. Historic status and zone: whether the lot is in a landmark or historic district or a Hillside Overlay, which set your size, height and visibility limits ².
2. Pasadena Water & Power: make an appointment with PWP to find conflicts with utility equipment or easements before you design ¹⁴. Pasadena runs its own utility, so LADWP rules do not apply.
3. Fire sprinklers: needed only if the main house already has them ¹⁵.
4. Fee track: decide before filing whether you will stay at or under 900 sq ft, sign a Housing Agreement, or use the Standard Plan; the permit portal asks those three questions, and a wrong answer causes delays or fee errors ⁴.
5. Timeline: once a complete application is in, the city must approve or deny it within 60 days ⁹.

Quick answers

Sources

1. Accessory Dwelling Units (city ADU page): regulations, permitted-zones table, historic contact, fire sprinklers, Second Unit program, City of Pasadena Planning & Community Development. Facts checked 2026-10-13
2. Ordinance No. 7420 (adopted Apr. 15, 2024), Exhibit 1: PMC Section 17.50.275 Accessory Dwelling Units and Junior Accessory Dwelling Units, City of Pasadena (City Council agenda, Apr. 15, 2024). Facts checked 2026-10-13
3. Ordinance No. 7420, Exhibit 1, Section 17.50.275.D Development standards, City of Pasadena (City Council agenda, Apr. 15, 2024). Facts checked 2026-10-13
4. Accessory Dwelling Units (city ADU page): Reduced Fees for ADUs on Single-Family Sites, Impact Fees, Housing Agreements, Property Taxes, City of Pasadena Planning & Community Development. Facts checked 2026-10-13
5. Ordinance No. 7420, Exhibit 1, Section 17.50.275.D.3 Hillside Overlay Districts, City of Pasadena (City Council agenda, Apr. 15, 2024). Facts checked 2026-10-13
6. Review of Pasadena's Accessory Dwelling Unit (ADU) Ordinance under State ADU Law, findings letter dated Feb. 26, 2025, California Department of Housing and Community Development (HCD). Facts checked 2026-10-13
7. Accessory Dwelling Units (city ADU page): Parking Criteria, City of Pasadena Planning & Community Development. Facts checked 2026-10-13
8. Agenda Report, May 5, 2025: Adopt a Resolution Amending the FY 2025 General Fee Schedule to Reduce or Waive Various Fees for Accessory Dwelling Units (ADUs), City of Pasadena Planning & Community Development (City Council agenda). Facts checked 2026-10-13
9. Accessory Dwelling Unit Handbook (March 2026): impact fees, owner-occupancy, historic districts, 60-day permitting, California Department of Housing and Community Development (HCD). Facts checked 2026-10-13
10. Agenda Report, July 22, 2019: Adoption of a Zone Change to Designate a Landmark District Overlay for the Arden Road Landmark District (LD-28), City of Pasadena Planning & Community Development (City Council agenda). Facts checked 2026-10-13
11. Historic Preservation Documents: Design Guidelines for Historic Districts, Certificate of Appropriateness, Landmark District Conservation Plans, City of Pasadena Planning & Community Development. Facts checked 2026-10-13
12. ADU Standard Plans Program, City of Pasadena Planning & Community Development. Facts checked 2026-10-13
13. Pasadena Second Unit ADU Program, City of Pasadena Housing Department. Facts checked 2026-10-13
14. Permitting an Accessory Dwelling Unit (ADU): ADU Checklist / Process Diagram, City of Pasadena Planning & Community Development. Facts checked 2026-10-13
15. Accessory Dwelling Units and Automatic Residential Fire Sprinkler System Requirements (Office of the State Fire Marshal information bulletin, hosted by the City of Pasadena), California Office of the State Fire Marshal. Facts checked 2026-10-13

Greenlight is not a contractor, architect or engineer, and this is not legal advice. Rules change; every fact here shows the date we last checked it.