How tall can I build in RH-1?

The baseline is 35 feet for any dwelling in RH-1, RH-1(D) or RH-1(S), under Planning Code § 261 — but the hill moves the number. If the rear of your lot sits 20+ feet higher than the front, the limit rises to 40 feet; if the rear is 20+ feet lower , it drops to 30; and 40+ feet lower drops it to 25. Height is measured per § 260, which is its own art form — measure before you design.

What's the difference between RH-1, RH-1(D) and RH-1(S)?

Three flavors of the same one-family idea, per § 209.1 : plain RH-1 is row-house-style single-family homes on ~25-foot lots without side yards; RH-1(D) is detached houses on wider lots with side yards (think westside tracts); RH-1(S) allows a minor second unit — typically a small ground-floor unit subordinate to the main home.

Can I add a unit in RH-1?

The district's own pattern is one house — but ADUs are part of the picture: even the special-district rules for RH-1 areas publish floor-area ratios for "One Dwelling Unit with ADU " ( § 249.3 ), and state ADU law applies in San Francisco like everywhere else. See our San Francisco ADU rules page for what's allowed on an RH-1 lot.

What is my front setback in RH-1?

Whatever your neighbors already have, roughly speaking. § 132 requires new buildings and additions in RH districts to be set back at least as deep as the adjacent building with the shortest front setback — a contextual rule designed to keep block faces aligned, rather than a fixed number.

RH-1 Zoning in San Francisco, Explained

Your parcel report says RH-1 and the listing calls it "prime single-family zoning." Here's what that actually allows: one house on a narrow lot, a 35-foot height ceiling that moves with the hill, setbacks copied from your neighbors — and more flexibility than the label suggests.

The parcel report says RH-1, the listing agent says "prime single-family zoning," and you're left wondering what you could actually do with the lot — add a floor? A unit over the garage? A bigger house? RH-1 is San Francisco's most common flavor of house zoning, and its rules are specific enough that the label alone tells you a lot.

Here's the decoded version: RH-1 is a "Residential, House — One-Family" district under Planning Code § 209.1 — single-family houses, typically on 25-foot-wide lots, with dwellings capped at 35 feet of height (adjusted up to 40 or down to 25 on sloped lots per § 261), front setbacks matched to your neighbors (§ 132), and the mid-block rear-yard pattern the city famously protects.

What the code says RH-1 is

The Planning Code describes the district in unusually plain language:

"These Districts are occupied almost entirely by single-family houses on lots 25 feet in width, without side yards." — § 209.1

RH districts as a family are meant to "recognize, protect, conserve, and enhance" areas of houses and small buildings with limited width and height, rear yards, and mid-block open space. RH-1 comes in three flavors:

District	Character (per § 209.1)
RH-1	One-family row-house pattern: ~25-ft lots, no side yards, front setbacks common, rarely over 35 ft
RH-1(D)	One-family detached: wider lots, side yards, larger homes — hillside tract neighborhoods
RH-1(S)	One-family with minor second unit: a small, subordinate unit, often a converted ground floor

The numbers that shape a project

Height: 35 feet, but the hill votes. § 261(b) caps dwellings in all three RH-1 flavors at 35 feet, then adjusts for topography: rear of lot 20+ feet above the front → 40 feet allowed; rear 20+ feet below → 30 feet; rear 40+ feet below → 25 feet. On San Francisco's grades, this single subsection decides many third-floor dreams. (Height is measured per § 260 — at the curb, with its own technicalities.)

Front setback: match the block. Instead of a fixed dimension, § 132 requires any new building or addition to sit at least as deep as the shallower of the two adjacent buildings' setbacks. The goal is an even street wall — and it means your buildable envelope literally depends on your neighbors' houses.

Rear yard and the rest. The dimensional controls (rear yards, open space, exposure) live in Article 1.2 of the Planning Code alongside § 132 — the article index is the map to them.

The overlay trap: your block may have extra rules

An RH-1 label is not always the whole answer, because San Francisco layers special use districts on top of base zoning. Two live examples for RH-1 areas: the Oceanview Large Residence Special Use District requires Conditional Use approval for homes with five or more bedrooms or floor-area ratios above 1:1 (1.15:1 with an ADU — the ADU's floor area doesn't count against you), and the Corona Heights Large Residence SUD imposes similar large-home review. Same RH-1 base zoning, different outcome by neighborhood — always check the sectional zoning map for overlays before sizing a project.

"One-family" isn't quite the last word

The name says one-family, and the district's pattern is one house per lot. But the code itself acknowledges more: RH-1(S) exists specifically for a minor second unit, and the special-district FAR tables above publish ratios for "One Dwelling Unit with ADU" — accessory dwelling units are a normal part of RH-1 life under state law. If adding a unit is the goal, start with our San Francisco ADU rules page, then confirm how your specific lot's overlays and topography interact with it.

For everything else about building in the city — codes, permits, and the rest of the zoning families — see our San Francisco hub.

What Does RH-1 Zoning Mean in San Francisco?