Six Inches Kept This SF In-Law Illegal. The Fix: Over $1 Million.

Supervisor Alan Wong announces his ceiling-height ordinance at San Francisco City Hall on June 26. Photo by Neal Wong, Richmond Review/Sunset Beacon.

Katherine Roberts has owned her Cole Valley house for about 23 years, and for much of that time she has tried to legalize the lower-level unit a previous owner built without permits, only to learn that bringing its ceiling up to city standard would mean excavation and foundation work reported at well over $1 million. San Francisco requires habitable rooms to have ceilings of at least 7 feet 6 inches, six inches more than the 7-foot minimum in the California Residential Code, and Supervisor Alan Wong's pending ordinance, File No. 260623, would cut the city's rule back to the state line.

The short version:

• San Francisco requires 7 feet 6 inches of ceiling in habitable rooms; the California Residential Code requires 7 feet. File No. 260623 would lower habitable rooms to 7 feet and other rooms to 6 feet 8 inches.
• The ordinance was introduced June 26, was on the July 8 agenda of the Department of Building Inspection's Code Advisory Committee, and is pending before the Board of Supervisors' Land Use and Transportation Committee.
• It changes one number. Fire safety, exits, structure, electrical, plumbing, ventilation, and natural-light rules all still apply to any unit you legalize or build.

From the text

Two documents tell you what is on the table. The first is the city's own ADU guidance, which still states the rule every current applicant is held to:

"ADUs must be a minimum of 220 sq ft and have a minimum 7.5 ft ceiling heights"

That line comes from the city's Design an ADU that meets City codes page. The second is the July 8 Code Advisory Committee agenda, which describes the proposal in one sentence:

"Discussion and possible action regarding proposed ordinance amending the Housing Code to reduce the minimum ceiling height for habitable rooms to seven feet and other rooms to six feet eight inches. (File No. 260623)"

Note the second number. Rooms that are not habitable would get their own lower floor of 6 feet 8 inches, which matters in a converted garage where the ductwork and the beam line never agree. Which rooms count as which is a definitions question worth settling at plan check.

What changed, and where it came from

The rule change grew out of Wong's "Dumb Laws Contest," launched in March, which drew more than 200 submissions. The ceiling rule won. At the June 16 Board of Supervisors meeting, SFist reported, Wong honored Roberts and Sunset resident Mike Nohr, whose entries both targeted the ceiling standard. Nohr said the cost of compliance has kept his own in-law unit off the rental market.

Ten days later Wong announced the draft at City Hall. "The only thing we're doing is removing a local requirement that exceeds state standards without providing additional safety," he said, according to the Richmond Review/Sunset Beacon. Asked why San Francisco adopted the stricter number in the first place, he said he did not think there was a good reason.

Do the math on Roberts's house and the rule starts to look like a tax on geometry. Well over $1 million to gain six inches is more than $166,000 per inch. It is a six-inch rule. It has had a two-decade career.

Who wins, and who still has work to do

Owners of existing, unpermitted in-laws. This is the group the ordinance is written for. San Francisco's Dwelling Unit Legalization Program lets you legalize one unwarranted unit per lot under Planning Code Section 207.3, and DBI offers an initial screening with no filing fee that estimates what legalization would cost. Today that estimate can turn on six inches you cannot buy without digging. As we noted when California widened its ADU amnesty under AB 2533, the state already bars a city from denying legalization of a pre-2020 unit over code violations unless a real health or safety fix is needed. Whether a city can treat six inches of local ceiling rule as that kind of fix is an argument this ordinance would make moot.

First-time ADU clients building new. If you are designing a garage or ground-floor conversion in a Sunset or Richmond row house, six inches is the difference between keeping the existing slab and lowering it. The Sunset Beacon's coverage notes the change could also make new construction cheaper, since lower ceilings take less material, so the savings are not limited to legalization.

Tenants. If you rent an in-law that was never permitted, this ordinance does not change your lease, and it does not force your landlord to do anything. What it can change is whether legalization is affordable. Wong said thousands of in-laws are already lived in without permits, and some sit empty because owners fear fines. The city's legalization FAQ sends questions about rent-control status to the San Francisco Rent Board and the San Francisco Tenants Union, and that is the right first call before any work starts.

What does not move. Every other requirement stays. The legalization FAQ lists ceiling height alongside ventilation, light, fire safety, and egress, and it points to SFFD Administrative Bulletin FS-05 for ground-floor sprinkler requirements. A basement that clears 7 feet but lacks the required exits, light, and ventilation is still not a legal apartment.

Our read: the six inches were never about safety, and the ordinance deserves to pass, but owners should not mistake it for amnesty. It removes the most expensive fix on the list for a lot of units. It does not remove the list.

The cross-street check. The 7-foot line Wong wants is the one the California Residential Code already sets, and absent a local amendment it is the number an owner in Los Angeles or San Diego designs to. New York arrives at the same place by a different road: as we covered for Brooklyn garden apartments, a NYC basement ADU has to clear a 7-foot ceiling and give every room a real window, and a cellar cannot be legally rented at all. Of the markets where we have checked the rule, San Francisco is the only one asking for 7 feet 6 inches. If the ordinance passes, a Sunset basement and a Bed-Stuy basement will face the same 7-foot number for the first time.

What to watch

The ordinance needs a hearing and vote at the Land Use and Transportation Committee, then a vote of the full Board. Watch two other things. First, whether the Building Inspection Commission, which the Code Advisory Committee advises, weighs in before the committee hearing. Second, whether the city's ADU guidance page is updated when the rule changes; until it is, expect the old 7.5-foot line to keep appearing on handouts and plan checks, and bring the ordinance number with you.

If you are pricing the other fixes on your legalization list, A-du's services marketplace is where to find a contractor for the pre-application walk-through.

The next date to watch is the committee hearing. Once it is on the calendar, you will know how long the six inches have left.

Elsewhere on the ADU beat

• LADBS has revised its ADU and JADU standards bulletin, IB P/BC 2026-150, to track AB 2533 and the city's ADU ordinance, LADBS.
• Oregon's land-use agency has moved into phase two of its Middle Housing Oregon Homes rulemaking, which runs through December 2027 and includes a model residential system development charge, Oregon DLCD.
• San Diego's 2026 Land Development Code update carries corrections to the ADU Home Density Bonus Program and its community enhancement fee, City of San Diego.