ADU Constructionin Pasadena, CA
ADU construction in Pasadena follows Municipal Code section 17.50.275 plus state law, and a complete application is reviewed without a hearing. Conversions have no size cap, a new 800 square foot unit gets 4 foot setbacks, and larger units in landmark districts or on hillsides meet street-view and size limits. The City also runs an ADU loan program.
Pasadena is not a blank slate for backyard units. The City's adopted Housing Element counts 85 percent of its housing stock as built before 1990, Bungalow Heaven alone holds more than 800 small Craftsman homes from 1900 to 1930, and the City's own first ADU, a 534 square foot one-bedroom behind a City-owned house on Waverly Avenue, was still being built when Pasadena Now reported it on July 2, 2021. The lots that matter here are mostly older lots behind older houses, and each parcel's overlays are part of the answer.
MDG Builders (CSLB #1040337) is the general contractor on the contract. We assess the lot, work with a designer on the plans, file with the Permit Center and sequence the build, while foundation, framing, plumbing, electrical and finish crews are separate licensed subcontractors whose licenses and certificates of insurance you can request. Statewide costs and the garage conversion checklist are on our ADU construction page, and the rest of our Pasadena work is on the Pasadena overview.
What Pasadena's code and Permit Center say about ADUs
Where adu construction permits come from in Pasadena: City of Pasadena Planning & Community Development Department, Permit Center.
Can you build an ADU in a Pasadena historic district?
Yes, with a visibility condition. In section 17.50.275 as posted on the City's code host, updated October 4, 2026, a larger ADU on an individually designated historic property, or in a landmark or historic district, must not be visible from the public right-of-way unless that requirement would prevent creating the unit. The test applies to what the section calls non-exemption ADUs. The three state-protected types, a conversion, an 800 square foot new unit with 4 foot setbacks and a junior ADU, run on a separate track.
The City says it has designated six areas as historic districts, and Bungalow Heaven has been a landmark district since 1989, according to Wikipedia. On a lot in a district like that, the backyard behind a small house is the likely site, and how much of it the street can see becomes a design question. A single story set behind the house answers it differently from a two-story unit near the alley, so we confirm the parcel's district and sight lines at the first site visit.
A conversion avoids the question when the garage already stands. The City's preservation page says exterior alterations visible from the street in a landmark district need a Certificate of Appropriateness, so ask Design and Historic Preservation how that interacts with the ministerial ADU review before anything is drawn. Our guide to ADU versus JADU rules explains the unit types in plain English.
Check the street-view rule before choosing between a new unit and a conversion.
Build an ADU in Pasadena: how big, how tall and how close to the lot line?
The code text we read sets the numbers. A new ADU on the state-protected 800 square foot track gets 4 foot side and rear setbacks. Beyond that, a detached new unit can reach 1,200 square feet, an attached one 850 square feet for a studio or one bedroom and 1,000 square feet with more bedrooms, and the smallest allowed unit is 150 square feet. Conversions inside existing space carry no size limit.
Height is 16 feet in hillside areas, visible historic areas and for exemption units in a front yard, and 18 feet otherwise, with more for transit and multistory lots and up to 2 extra feet to match a roof pitch. Larger new units keep 6 feet of eave-to-eave separation from other buildings, and a unit over 800 square feet meets the zone's front setback. Single family sites need one parking space per unit, with exceptions for conversions, historic districts, exemption units and transit within half a mile.
Rentals of ADUs created on or after January 1, 2017 must be longer than 30 days, so nightly rental is out, and an ADU cannot be sold separately unless a qualified nonprofit builds it under Government Code section 66341. Our ADU cost table shows what these sizes cost to build.
Garage conversion ADU in Pasadena: parking, setbacks and the 150 square foot add-on
A garage is the quickest route in an older neighborhood. The code allows a conversion within existing space, with up to 150 square feet added only for access, and requires no setbacks beyond what fire safety demands. Replacement parking is not required when a garage or carport is demolished or converted. The unit shares the main driveway, and a second driveway is allowed only from an alley where replacement parking is required.
The Permit Center requires online submittal for ADUs. Its residential plan list asks for dimensioned plans, a foundation plan where floors change, smoke and carbon monoxide alarm locations, plumbing fixtures with clearances, electrical locations and a Title 24 report, and we confirm with the plan checker whether an old garage slab can stay. For comparison, a neighboring city's checklist is in our Los Angeles garage conversion guide, though Pasadena's own requirements govern here.
A junior ADU is the lightest version: up to 500 square feet inside the house, an attached garage included, with separate exterior access and an efficiency kitchen. If it shares a bathroom with the house, either the house or the junior unit must be owner-occupied, and a covenant is recorded before permitting.
ADU construction on a Pasadena hillside lot or in a fire hazard zone
The code gives hillside overlay districts, other than HD-1, their own limits. On streets up to 26 feet wide, new construction is capped at 800 square feet, and on other hillside properties a detached new unit is capped at 1,000 square feet. The City's design parameters sheet requires a soils report for hillside construction such as decks, retaining walls and pools, and Chapter 14.05 of the Municipal Code, the Hillside Grading Ordinance, governs excavation. Ask Building and Safety whether your unit triggers one.
The Fire Department places the fire hazard severity zones generally in the Arroyo Seco, west and north of the 210 freeway, and upper Hastings Ranch. CAL FIRE says Chapter 7A, which covers ember-resistant roofs, vents and glazing, applies to new buildings in High and Very High zones, and Pasadena adopted the 2025 Wildland-Urban Interface Code effective January 1, 2026, and our Pasadena roofing page covers the roof side. The state housing agency's handbook adds that a newly built detached ADU needs solar panels under the Energy Code, while conversions and additions do not.
The Eaton Fire destroyed 185 structures in Pasadena, and a 2025 state law, Government Code section 66328, lets an ADU's certificate of occupancy come before the main house's in an emergency-declared county once inspections pass. The City also reduced or waived plan check and permit fees for eligible rebuilds in August 2025. Its pause on SB 9 applications in Very High zones inside the fire boundary concerns lot splits, not ADUs, but confirm your parcel.
How long does an ADU permit take in Pasadena, and can the City lend money?
State law sets the clocks. The agency has 15 business days to say whether an application is complete and 60 days after that to act, and silence means deemed approval under Government Code section 66317 as amended effective January 1, 2026. The Permit Center says projects needing more review take roughly two to four weeks with about three submissions. Pasadena Water and Power is on the City's list of agencies whose approval may be required before a permit issues, so utility questions go in early.
The City's Second Unit ADU Program, run by the Department of Housing, offers loans of up to $250,000 at 1 percent simple interest with no payments for three years, for a new rental unit in the backyard, with a City-assigned construction manager. The page lists the application window as open, reviews applications on a rolling basis with limited spaces, and suggests renting to a Pasadena Housing Choice Voucher tenant. We read it on November 6, 2026, and another source quotes a different cap, so confirm the terms before planning around them.
A City-managed build is a different arrangement from a private contract with a general contractor, so decide which you want before applying. If you hire us, the proposal lists each permit, each utility charge as an allowance and the City's fees as separate lines, because we found no Pasadena ADU fee schedule to quote. State law exempts ADUs of 750 square feet or less from impact fees, and utility connection charges are separate. Our note on how general contractors use subcontractors explains the contract.
ADU details from Pasadena-area projects
Three views of the framing, utilities and finished space behind an ADU in Pasadena. Tap a photo to enlarge it.
What adu construction costs around Pasadena
Our ADU cost table puts a garage conversion at roughly $100,000 to $200,000 and a new detached unit of 400 to 800 square feet at $200,000 to $400,000, built from the UC Berkeley and Terner Center studies and the 2025 Cost vs. Value report, which shows a Los Angeles ADU job at $178,536. Those are regional figures, not Pasadena quotes, and City fees appear as separate lines. Compare the same job in the City of Los Angeles on our Los Angeles overview or Los Angeles ADU page. If a bigger house is the other option, our room addition page weighs the two. Fencing in Pasadena often follows a new unit, and the Glendale overview shows how the next city over handles the same questions.
| 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 |
Pasadena ADU, historic lot and garage conversion questions
Can I build an ADU in a Pasadena historic district?
Yes, with limits. Larger ADUs on individually designated properties or in landmark and historic districts must not be visible from the public right-of-way unless that would prevent creating the unit, per section 17.50.275. Conversions, 800 square foot units and junior ADUs are state-protected types. Confirm your parcel's district with City Planning.
Do I need to replace parking when I convert a garage to an ADU in Pasadena?
No. Section 17.50.275 says replacement parking is not required when a garage or carport is demolished or converted for an ADU. A new unit on a single family site needs one space, with exceptions for conversions, historic districts, exemption units and transit within half a mile. Check which exception fits your parcel.
How big can an ADU be in Pasadena?
A detached new unit can reach 1,200 square feet, an attached one 850 square feet for a studio or one bedroom and 1,000 with more bedrooms, and a junior ADU 500 square feet, per section 17.50.275. Hillside streets up to 26 feet wide cap new construction at 800 square feet. Conversions inside existing space have no size limit.
How long does it take to get an ADU permit in Pasadena?
State law gives the City 15 business days to call an application complete and 60 days after that to act, with silence meaning approval. The Permit Center says projects needing more review take roughly two to four weeks and about three submissions. We found no published City average for ADUs, so we plan around corrections.
Can I build an ADU on a hillside lot in Pasadena?
Often yes, with smaller size limits. Hillside overlay districts other than HD-1 cap new construction at 800 square feet on streets up to 26 feet wide and detached new units at 1,000 square feet elsewhere. Soils reports apply to hillside construction, and fire zone parcels follow ignition-resistant rules. We check the overlay and fire map first.
Does Pasadena offer a loan to build an ADU?
Yes. The Department of Housing's Second Unit ADU Program lists loans of up to $250,000 at 1 percent simple interest, no payments for three years, a City construction manager and rolling review with limited spaces. We read the page on November 6, 2026, and another source quotes a different cap, so confirm eligibility and terms with the City.
Can I rent my Pasadena ADU on Airbnb?
No, not for short stays. Section 17.50.275 requires rentals of ADUs and junior ADUs created on or after January 1, 2017 to be longer than 30 days. The City also has its own short-term rental rules in its code, so check those before you plan nightly income. Longer rentals follow normal landlord law.
Do I pay impact fees on an ADU in Pasadena?
Not if the unit is 750 square feet or less. Government Code section 66311.5 bars impact fees on ADUs of that size, and larger units pay in proportion to the main house. Utility connection and capacity charges are separate. We could not verify Pasadena's fee amounts, so the proposal lists them as allowances.
Can I sell my ADU separately from the house in Pasadena?
Generally no. Section 17.50.275 bars selling an ADU separately from the main home unless a qualified nonprofit develops it under Government Code section 66341. A city may also adopt a condominium ordinance under section 66342. We found no Pasadena condominium ordinance in the sources we read, so assume one title.
Can I build an ADU on a lot burned in the Eaton Fire?
Yes, the state has made it easier. Government Code section 66328 lets an ADU's certificate of occupancy precede the main house's in an emergency-declared county after inspections pass. The City reduced or waived plan check and permit fees for eligible rebuilds in August 2025. Ask the Permit Center how your parcel's zone and rebuild status interact.
Describe your Pasadena lot
Tell us the neighborhood, whether the house is in a historic district or on a hillside, and whether you have a garage to convert, and we will plan the site visit around the parcel.