Building an ADU in South Pasadena. Rules, costs, timeline.

Can I build an ADU in South Pasadena?

Five things to know before you start

If you read nothing else on this page, read these. They are the five points that change the most South Pasadena projects.

How many units your lot can hold

South Pasadena is a 3.4-square-mile independent city between Pasadena, San Marino and the northeast Los Angeles neighborhoods, on lots that mostly run 4,000 to 8,000 square feet with a housing stock that skews early twentieth century. The ordinance treats those lots more generously than their size suggests. SPMC § 36.350.200(E)(1)(a) allows one ADU, attached or detached, plus one junior ADU — and then states that under Gov. Code § 66323 an owner may also convert an existing structure to an ADU in addition to those two.

That is the same stack Gov. Code § 66323(a)(1)–(2) requires. What changed in 2025 is that the City wrote it down. The previous version of the local text read as one ADU plus one junior ADU, and everyone had to argue preemption to get to the real number. There is nothing left to argue.

What the city cannot do

Review is ministerial. SPMC § 36.350.200(C) provides that ADU applications are considered ministerially, at staff level, on objective standards, within 60 days of being deemed complete, and are deemed approved if the City fails to act — citing Gov. Code §§ 66316 and 66317 directly. There is no hearing and no discretionary design review. Even where an ADU rides along with a new house that does need discretionary approval, the code says the ADU permit is still considered without discretionary review or hearing.

The City may not require you to live on the property. It may not demand replacement parking when you convert a garage. It may not use lot coverage, floor-area ratio or open-space rules to stop an 800-square-foot ADU. And on a unit that qualifies under Gov. Code § 66323, it may not apply any objective development or design standard beyond the ones that section itself authorizes — a limit the local code now repeats at the head of subsections (E), (F), (G) and (J).

What an ADU costs here in 2026

An ADU budget has three parts that behave very differently. The plan fee is fixed and known before you start. Construction is a range that narrows once we see your lot. City fees are modest by comparison, and in South Pasadena one of them is published as a flat number while the rest are tied to construction valuation.

What the City of South Pasadena charges

The City publishes one flat ADU line: $633.00 for ADU Review – Ministerial, in the Schedule of Fees for Fiscal Year 2026-2027 adopted by Resolution No. 8000 on May 6, 2026 and effective July 6, 2026. Building permit and plan-check fees are not a flat ADU charge — they are computed from project valuation under the Building Division Fee Schedule, which also directs an ADU to the additional-parcel line for address assignment rather than the higher base house-number fee. Where a front-yard ADU triggers a landscape plan, the schedule carries separate landscape plan check and inspection fees. Ask the Planning counter for a written estimate against your valuation before you set a budget.

What it returns

South Pasadena sits inside the Los Angeles–Long Beach–Glendale HUD Metro Fair Market Rent Area. HUD’s revised FY 2026 Fair Market Rents for that area, published at 91 FR 21301 and effective May 21, 2026, are $2,079 for a studio, $2,328 for one bedroom, $2,903 for two bedrooms and $3,681 for three.

Read those as a floor rather than a forecast. Fair Market Rents average across an entire metropolitan area and across housing of every age and condition, most of it decades older than anything you would build now. A new, permitted, detached two-bedroom unit typically rents at or above the two-bedroom figure, and South Pasadena has two demand drivers that push the same direction — a well-regarded unified school district and a Metro A Line station at Mission Street. What your street will actually fetch is a question for a local agent, and worth asking before you commit.

The other half of the return is resale. A permitted ADU adds recorded square footage that comps into the sale of the property. An unpermitted conversion does the opposite: it is a disclosure problem and a financing problem, which is why both the City and the state built legalization paths for existing units.

When an ADU isn’t the right move

Not every South Pasadena property is a good candidate, and it is cheaper to learn that now than after you have paid for drawings. Four situations where we would tell you to wait, change type, or not build:

• Your numbers depend on short-term rental income. They will not work. SPMC § 36.350.200(K) bars renting an ADU for less than 30 days and allows the City to record a deed restriction saying so, and Gov. Code § 66323(e) requires the same. Run the math on a month-to-month tenancy or reconsider the project.
• You need to sell the unit as its own condominium. South Pasadena has not adopted an AB 1033 opt-in, which is the precondition Gov. Code § 66342 sets. The nonprofit route the local code does allow is narrow and is not a general-purpose exit — see the separate-sale discussion below.
• Your only buildable spot is a character-defining accessory structure. On a historic property, SPMC § 36.350.200(J)(6)(a) bars demolishing an accessory structure found to be a character-defining feature in order to build an ADU. If the old garage is the reason the property is listed, the answer is a conversion or a different location, not a teardown.
• The fire-area siting rule leaves nothing worth building. In the high fire hazard area a detached ADU has to sit within 150 feet of the front property line, sprinklers are required, and a narrow street adds a parking space. On a long lot with the house well forward, those three together can squeeze a detached unit out. A conversion or a junior ADU usually returns more than forcing a new build into the gap.

The rules that make this city different

South Pasadena has no Coastal Zone. What it has instead is one of the most intact early-twentieth-century housing stocks in Los Angeles County and a fire-hazard designation over the southwest quarter of the city, and both are written into the ADU section rather than left to a separate overlay.

Historic properties — a new design code, and the way around it

Subsection (J) did not exist before the 2025 rewrite. It replaced a short and blunt rule — one story, 16 feet, rear placement — with a full design code, and in doing so it loosened the height limit while tightening the detailing. A homeowner reading anything written before 2025 will get this backwards.

Start with what the definition catches. SPMC § 36.350.200(A)(8) covers a property designated as an individual landmark or as a contributor to a designated historic district, and separately any property identified on a City-adopted inventory as eligible to be either, as authorized by Health and Safety Code § 18955. The second limb has never been through a designation hearing. Plenty of owners do not know they are on it.

If subsection (J) applies, three permitted types exist: a conversion of an existing accessory structure with or without added floor area, a new detached ADU, and a junior ADU inside the envelope of the primary dwelling. An attached ADU is not permitted at all on a historic property. Height may not exceed the height of the primary dwelling, except that 16 feet is always available even where the main house is shorter. A two-story ADU is permitted at 18 feet flat plus a one-foot parapet or 22 feet pitched, where it stays lower than the primary dwelling and the primary dwelling is itself two stories — with an exception on a hillside lot, where a two-story unit downslope at the rear of a one-story property qualifies if it still reads lower from the street.

Where the design code does apply, it is specific. The roof type and pitch must match the primary dwelling or the accessory structure being converted. Roof material must match, with vinyl tile and cement shake prohibited outright and three substitutions allowed — composition shingle for wood shingle, cement tile for clay tile, solar shingle for asphalt or wood shingle. Cladding material and orientation must substantially match, but has to be differentiated by color, profile, width or texture, so a copy is as wrong as a contrast. Doors and windows must use the same or similar materials, windows must share the predominant orientation, and no exposed vinyl is permitted on them. Dormers, bay windows, arched windows and shutters are allowed only where they already appear on the main house.

Review stays ministerial and staff-level. Cultural Heritage Commission review is triggered only where a new detached ADU or an accessory-structure addition does not comply with the subsection (J) standards. On demolition, an accessory structure older than 45 years gets a staff-level Historic Resource Evaluation Report, and a structure found to be a character-defining feature may not be demolished to make room for an ADU at all.

The high fire hazard area south of Monterey Road

SPMC § 36.350.200(A)(7) defines the area as the part of the city south of Monterey Road and west of Meridian Avenue, extending to the city border in each direction, as established in Chapter 14 of the municipal code. That chapter moved in 2025. Ordinance No. 2404 rewrote SPMC § 14.1 so that the City now adopts the State Fire Marshal’s Local Responsibility Area Fire Hazard Severity Zones map dated March 24, 2025, designates the same south-of-Monterey area as a high fire hazard severity zone under Gov. Code § 51179 by a local map dated August 20, 2025, and treats a parcel shown partly in the very high zone and partly in the high zone on the state map as very high throughout. Class A roof assemblies are required in the high zone.

Inside that area, SPMC § 36.350.200(I) adds three requirements to everything else on this page. A property fronting a street narrower than 28 feet must provide one off-street parking space for the ADU, and the ADU may not displace existing parking for the main house — though a garage may still be converted if the removed spaces are provided elsewhere on the property in addition to the ADU’s. Fire sprinklers are required. And a detached ADU has to sit within 150 feet of the front property line so that a standard 250-foot pre-connected hose line reaches it, with a flag-lot alternative of 100 feet from a dry standpipe installed with the Fire Chief’s approval.

The ADU Amnesty Program

South Pasadena is one of the few cities in the area running a formal amnesty program for existing accessory dwelling units built without some or all of their permits. The City’s flyer describes the bargain plainly: bring the unit up to basic health and safety standards without the risk of fines or code enforcement action, with significant fee reductions and help identifying what needs to change. The route in is the ordinary ADU application from the Planning Division, marked “Existing – legalization.”

A parallel state right sits underneath it. Gov. Code § 66311.7 bars a city from denying a permit for an ADU or junior ADU built before January 1, 2020 on building-code grounds, unless correcting the violation is necessary to stop the building being substandard. That provision came from AB 2533 and was renumbered by SB 543, effective January 1, 2026. It applies whether or not the City is running an amnesty program, and where the two overlap the more permissive set of rules is the one to work from.

Multifamily lots

The multifamily rules moved a long way in 2025 and are now more generous than most homeowners expect. SPMC § 36.350.200(F)(2) allows up to eight detached ADUs on a lot with an existing multifamily dwelling, capped at the number of existing units on the lot, and two on a lot with a proposed multifamily dwelling. That matches the state floor at Gov. Code § 66323(a)(4)(A)(ii), added by SB 1211. Separately, non-livable space inside the existing building envelope — storage, boiler rooms, passageways, attics, basements, garages — may be converted into ADUs up to 25 percent of the number of existing units, with at least one always allowed.

Two details differ from the single-family standards. A one-story detached ADU on a multifamily lot gets 18 feet rather than 16 (§ 36.350.200(F)(4)), and where the multifamily standards conflict with the historic-property design code, subsection (J) controls (§ 36.350.200(F)(1)). Junior ADUs remain a single-family-only unit type.

Owner-occupancy and separate sale

No owner-occupancy requirement applies to an ADU here, consistent with Gov. Code § 66315. For a junior ADU, SPMC § 36.350.200(D)(1) still requires the owner to live in either the remaining portion of the primary residence or in the JADU itself.

On separate sale, the 2025 rewrite reversed the local position. SPMC § 36.350.200(D) now provides that an ADU may be sold or conveyed separately to low- or moderate-income persons in accordance with Gov. Code §§ 66340 and 66341, where a qualified nonprofit corporation built or developed it. That is AB 587, at Gov. Code § 66341, and it is mandatory statewide — it needs no city opt-in, and the City’s own information sheet says as much while noting the eligibility rules will not apply widely here.

The condominium route is a different statute and South Pasadena has not taken it. Gov. Code § 66342 requires a city to adopt an AB 1033 opt-in ordinance before an ADU can be conveyed separately as a condominium, and no such ordinance appears in the South Pasadena code. A junior ADU may not be sold separately under either route.