What You Can Build In Pasadena.
Pasadena's current ADU rules were adopted as Ordinance No. 7420 and took effect May 20, 2024. On a lot with an existing or proposed single-family home, you can build a detached new-construction ADU of up to 1,200 square feet, and every ADU must be at least 150 square feet. Attached new-construction ADUs are capped at 850 square feet for a studio or one bedroom and 1,000 square feet for two or more bedrooms.
New ADUs need just 4-foot side and rear setbacks, and a detached unit can generally rise to 18 feet and two stories, with two extra feet available near major transit to match the main home's roof pitch. The city also requires a 6-foot building separation, eave to eave, between a new detached ADU and other structures on the lot. A junior ADU of up to 500 square feet can be carved out of the house itself, and Pasadena allows an ADU and a JADU together on the same single-family lot, so a backyard unit like an Abodu does not use up your only option. Not sure what fits your yard? Check your lot and we will map it for you.
One quirk worth knowing: the California Department of Housing and Community Development reviewed Pasadena's ordinance in a February 26, 2025 findings letter and flagged several provisions as stricter than state law. Pasadena's own code says that when the two conflict, state law prevails, which generally works in the homeowner's favor.
Historic Districts, Hillsides, And Special Rules.
Pasadena is famous for its landmark and historic districts, and ADUs are still allowed in them. The rule under the city's ADU standards is that a new ADU on a 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 the unit from being built at all. A detached ADU that is visible from the street in a historic district is limited to 16 feet in height, so single-story backyard placements are the natural fit.
There is a silver lining: properties in historic districts are exempt from ADU parking requirements entirely. Elsewhere, the standard is one space per unit or per bedroom, whichever is less, and it is waived within a half mile walking distance of transit, for conversions of existing space, or when a car-share vehicle is within a block.
In Pasadena's Hillside Overlay Districts, new detached ADUs on most lots are limited to 1,000 square feet, and on lots served by narrow streets up to 26 feet wide, new construction is limited to the state-baseline 800-square-foot unit. Since so much of this is parcel-specific, the fastest move is to run your address through our lot check before you fall in love with a floor plan.
Standard Plans, Fees, And The 60 Day Clock.
Pasadena pioneered a pre-approved ADU Standard Plans program, with city-designed prototypes like a 374-square-foot studio and a 682-square-foot two-bedroom offered at no cost. Know the fine print, though: general citywide use of the program expired December 31, 2025, and as of January 1, 2026 the standard plans are reserved for properties red-tagged in the Eaton Fire. Modifications to the plans are not allowed, no matter how minor, and site-specific review of setbacks, slope, and trees still applies.
The fee side is friendlier. Under reductions effective May 6, 2025, ADUs of 900 square feet or less get 25 percent reduced permit fees and a residential impact fee exemption, and projects using standard plans or signing an affordability agreement get a 50 percent plan check discount.
Timing is protected by state law. Per the HCD ADU Handbook, Pasadena must approve or deny a complete ADU application within 60 days, and if it does neither, the application is deemed approved under Government Code section 66317. Abodu's permitting team has the drawings, calculations, and responses ready so that clock works for you, not against you. See how the process works from first call to installed home.
ADUs On Multifamily Lots.
Pasadena's code lets owners of multifamily properties convert non-livable space, think storage rooms, attics, basements, and garages, into ADUs, with at least one unit and up to 25 percent of the existing unit count allowed, plus up to two detached new-construction ADUs with 4-foot setbacks and a 16-foot height limit, rising to 18 feet for multistory buildings or lots near major transit.
State law has since moved further. In its review of Pasadena's ordinance, HCD pointed to SB 1211, which as of January 1, 2025 allows up to eight detached ADUs on a lot with an existing multifamily dwelling, capped at the number of existing units, and Pasadena's code defers to state law where they conflict. If you own or manage apartments in Pasadena, that is a serious density opportunity. See how Abodu deploys ADUs for multifamily properties at scale.
What It Actually Costs.
Custom site-built ADUs in California routinely exceed $250,000 before change orders, and the final number usually is not known until the project is nearly done. Abodu works the opposite way: transparent published pricing: homes from $234,800 plus a published installation price, an expected all-in from $298,800 that covers design, permits, factory build, delivery, and installation, with no surprise line items in month eight.
Because your Abodu is built in a factory while Pasadena reviews the permit, the 60-day clock and the site work run in parallel instead of in sequence. Curious what that looks like step by step? Read how the process works, browse what neighbors say on our testimonials page.