Building an ADU in San Rafael: Rules, Fees and Permits

San Rafael at a glance

The rules table — from the ordinance, not a template

Every row below traces to Table 14.16.285 of the San Rafael Municipal Code or to the city's own ADU pages. If a row is not in the ordinance, it is not in this table.

Six things on this page exist nowhere else in Marin in this form: the 1,000 sq ft ordinance cap, the Eichler height rule, the 10-ft front-entry rule, the city's under-750 sq ft waiver list, the pre-approved plans programme, and the OpenGov ministerial process — plus a seventh, the legalisation path for pre-2020 units, covered below.

Size, height and setbacks

What the ordinance actually says

The 1,000 sq ft detached cap, Ord. 2002

Table 14.16.285 sets the detached maximum at 1,000 sq ft. Attached ADUs are capped at 1,000 sq ft or 50% of the existing primary home's floor area, whichever is less. A conversion — turning existing space, such as a garage, into a unit — carries no size cap in the table, because the building you already have sets the boundary. A junior ADU (JADU) inside the home caps at 500 sq ft under §14.16.286, with a deed restriction recorded and owner-occupancy as current state law provides.

Why other pages say 1,200 sq ft

Template guide pages for San Rafael — GatherADU and ADUSherpa among them — claim a 1,200 sq ft detached maximum. That figure does not match the ordinance of record located in our research: SRMC §14.16.285, Ordinance 2002, adopted December 6, 2021, says 1,000 sq ft. The 1,200 figure is real law in some other Marin towns and in state law for certain conversions, which is likely how it travelled — but it is not San Rafael's detached cap. Plan to 1,000 sq ft, and treat anything larger as a question to put to the city in writing, not as a starting assumption.

Two honest qualifications belong next to that cap. First, the state's 800 sq ft exempt unit is unaffected: California law guarantees a detached unit of up to 800 sq ft of interior livable space, at 4-ft side and rear setbacks, regardless of local lot-coverage, floor-area or open-space rules — the city's own FAQ confirms that treatment. Second, our research did not locate a post-2023 conforming amendment updating San Rafael's printed table for newer state law. Where state law is more permissive than the 2021 text, state law controls. One measurement note: from Jan 1, 2026, state law (Gov. Code §66321, as amended in 2025) measures ADU floor area as interior livable space — so the 1,000 sq ft cap is measured as interior livable space.

The Eichler-overlay height rule

The general table height is 16 ft for attached and detached ADUs, with a deviation path up to the underlying zone height where district setbacks are met. If your home sits in the Eichler-Alliance (-EA) overlay, a tighter rule applies instead: the ADU's height is limited to the height of the existing residence or 17 ft, whichever is less. On a single-storey Eichler, that can mean your house — not the 16 ft table figure — sets the ceiling for the ADU. Check the overlay before you fall in love with a two-storey design.

Front entry and corner-lot rules

Side and rear setbacks are 4 ft. The front setback follows the primary dwelling's standard. A detached ADU's front entry has its own rule: the entry must sit back 10 ft from any right-of-way. That entry rule shapes where the door — and often the whole floor plan — can go on a shallow lot. Corner and reverse-corner lots carry additional street-side provisions in the ordinance table, so a corner lot deserves a specific look before design work starts, not after.

The permit process

Step by step, through OpenGov

San Rafael reviews ADUs ministerially — a compliant application is decided against objective standards, not argued at a hearing. The clocks below are law, not estimates.

Those clocks cover the city's decision, not your whole project. Design, engineering, utility coordination and construction sit outside them, which is why the checker verdict separates the permit step from the full timeline instead of blending them into one optimistic number.

Fees

What San Rafael waives — and what it charges

Under 750 sq ft: the city's waiver list

The City of San Rafael states it directly on its accessory dwelling unit permit process and fees page (sanrafael.gov, as of Nov 2026): “For ADUs under 750 sq ft, these fees are waived: Impact fees; General plan maintenance; Street maintenance; Bedroom taxes.” That list is San Rafael's, in the city's words — it is broader and more specific than the general state exemption from impact fees at the same size threshold, and it is one reason a unit designed just under 750 sq ft can cost meaningfully less in fees than one designed just over it. If your plans are hovering near that line, the fee treatment belongs in the design conversation, early.

Everything else: valuation-based

Beyond those waivers, San Rafael publishes no ADU-specific flat fee. The remaining permit charges are valuation-based, calculated from your project's declared value under the city's Master Fee Schedule. That means any page quoting you a single flat San Rafael ADU permit fee is inventing it. Your real fee figure comes from the schedule applied to your project — and your builder's permit set is what sets the valuation it is calculated from.

One programme San Rafael homeowners often hear about does not automatically reach them: Marin County's fee waiver — up to $2,500 per ADU — covers unincorporated Marin County only. San Rafael is an incorporated city, so do not count the county waiver into a San Rafael budget. The county fee-waiver guide explains the scope in full, so you can check whether an address is inside or outside it.

Pre-approved plans

San Rafael's pre-approved ADU plans programme

The city runs a pre-approved ADU plans programme, stated on the same sanrafael.gov permit page (as of Nov 2026): “Using pre-approved plans — Pre-approved plans speed up the approval process. There are 2 types: Designed by the City; Designed by third-party professional.” The idea, under California's AB 1332 programme duty, is that a design the city has already reviewed once should not have to be reviewed from zero on every lot: a detached ADU using a pre-approved plan — or a previously permitted identical plan — must be decided in 30 days instead of 60 under state law.

Pre-approval speeds the design review; it does not skip the site. Foundation, setbacks on your parcel, utilities and the entry rule on this page still get checked against your lot. Treat the programme as a head start on the permit clock, and confirm the current catalogue and its conditions on the city's page before you build a plan around a specific design — programmes like this change as new plans are submitted and approved.

Legalising a unit, and San Rafael traps

The pre-2020 path, and the address-level traps

Legalising an unpermitted unit built before 2020

The city publishes a path to legalise unpermitted units built before 2020. It sits on the state framework (AB 2533): the agency works from a substandard-housing checklist focused on health and safety, may not deny legalisation solely for building-code violations that do not threaten health or safety, and may not charge impact fees or penalties for a qualifying unit — standard permit, plan-check and inspection fees still apply. If you own a garage conversion or backyard unit that was built without permits before 2020, this path is the difference between a paperwork problem and a permanent one. Start with the city's legalisation page, and get the unit's status settled before you sell, refinance or add further work.

Which sanitary district serves your address?

San Rafael is not one sewer system. Parts of the city are served by the San Rafael Sanitation District and others by the Las Gallinas Valley Sanitary District, and connection requirements differ by address. A detached ADU with its own kitchen and bathroom is a new sewer connection question in either district — but which district, and on what terms, depends on where your parcel sits. This is an early check, not a late surprise: confirm your district while the design is still flexible.

The hillside caveat, honestly labelled

San Rafael's 2021 ordinance history includes discussion of restricting ADUs on certain substandard hillside streets. Our research could not confirm the current status of that idea in the ordinance as it stands today, so this page does not present it as a live rule. If your lot is on a steep or substandard hillside street, ask the city directly, in writing, whether any street-specific limitation applies to your address — and do that before paying for design work.

A related honesty point: San Rafael does not publish per-permit open data for ADUs, so this page carries no permit statistics for the city — because there is no official per-permit record to build them from. Anyone showing you precise San Rafael ADU permit counts or average permit costs is working from something other than a published city record.

What it costs

San Rafael cost, in summary only

San Rafael projects price inside the locked Marin planning ranges: a garage conversion runs $120k–$220k, a detached one-bedroom ADU $300k–$500k, and a JADU inside the house $80k–$180k — planning ranges, estimates, not bids. Your sanitary district, your lot's slope and whether you land under the 750 sq ft fee line move you inside those bands. The full anatomy — what is included, what drives a Marin number up or down, and how fees stack — lives on the Marin ADU cost guide, and how matching to a builder works is on How it works.

Questions, answered

San Rafael homeowners ask us these

Related guides

Where to go next

Check your lot

Check your San Rafael address

Tell us the address and what you want to build. The checker is pre-set to San Rafael, so your verdict is measured against the 1,000 sq ft cap, the Eichler and entry rules, and the under-750 sq ft fee line on this page — in plain language, in about 60 seconds.