UPDATE ! In San Francisco, over 70% of the parcels are zoned for residential use. Due to the current critical housing crises, the City have made substantial changes to what you're allowed to build in these zones. Residents are finally seeing solid efforts from the City to facilitate building more units and faster. Though a more permissive zoning regulations and a streamlined or Ministerial permitting process, you could get permits for 2 new units on a property within 90 days.

All these changes happened as recent as of January 2024. The Ordinance 230446 modified multiple restrictions in the San Francisco Municipal code. One of the significant changes is the minimum lot size in San Francisco from 2,400 sqft to 1,200 sqft for all zoning districts. Along with this change, also the minimum lot frontage is now 20 feet for ALL zoning districts.

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Density Limit Exception for residential districts in San Francisco

Update: City of San Francisco passed an exciting ordinance that allows ALL residential zoned districts (RH-1, RH-1(D), RH-2 and RH-3) to have 4 units on any lot, or 6 units on corner lots. This ordinance is called Density Limit Exception and it concerns only the number of units homeowners could have on their property, and NOT the envelope or height of the building. The height limit will be the same as it has been for many years, along with the neighborhood restrictions on the building massing. As opposed to Senate Bill 9 (SB9), this ordinance doesn't benefit from the ministerial review process, or any other streamlined permitting process. If you want to know how much you can build on your property, you can find out easily by looking up your address.

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Update: on September 16th 2021, California passed Senate Bill 9 to allow property owners to split a single-family lot into two lots, add a second home to their lot or split their lot into two and place duplexes on each. The last option would create four housing units on a property currently limited to a single-family house. You can find a friendly description of SB-9 law in this article.

‍RH-1(D) Districts: One-Family (Detached Dwellings).

‍These Districts are characterized by lots of greater width and area than in other parts of the City, and by single-family houses with side yards. The structures are relatively large, but rarely exceed 35 feet in height. Ground level open space and landscaping at the front and rear are usually abundant. Much of the development has been in sizable tracts with similarities of building style and narrow streets following the contours of hills. In some cases private covenants have controlled the nature of development and helped to maintain the street areas.

RH-1 Districts: One-Family.

‍These Districts are occupied almost entirely by single-family houses on lots 25 feet in width, without side yards. Floor sizes and building styles vary, but tend to be uniform within tracts developed in distinct time periods. Though built on separate lots, the structures have the appearance of small-scale row housing, rarely exceeding 35 feet in height. Front setbacks are common, and ground level open space is generous. In most cases the single-family character of these Districts has been maintained for a considerable time.

RH-1(S) Districts: One-Family with Minor Second Unit.

‍These Districts are similar in character to RH-1 Districts, except that a small second dwelling unit has been installed in many structures, usually by conversion of a ground-story space formerly part of the main unit or devoted to storage. The second unit remains subordinate to the owner's unit, and may house one or two persons related to the owner or be rented to others. Despite these conversions, the structures retain the appearance of single-family dwellings.

RH-1(D), RH-1, and RH-1(S) Districts.

For buildings that submit a development application on or after January 15, 2019, the minimum rear yard depth shall be equal to 30% of the total depth of the lot on which the building is situated, but in no case less than 15 feet. Exceptions are permitted on Corner Lots and through lots abutting properties with buildings fronting both streets, as described in subsection (f) below. For buildings that submitted a development application prior to January 15, 2019, the minimum rear yard depth shall be determined based on the applicable law on the date of submission.

RH-1(D), RH-1, RH-1(S), RM-3, RM-4, NC-1, NCT-1, Inner Sunset, Outer Clement Street, Cole Valley, Haight Street, Lakeside Village, Sacramento Street, 24th Street-Noe Valley, and West Portal Avenue Districts. Rear yards shall be provided at grade level and at each succeeding level or story of the building.

SIDE YARDS, RH-1(D) DISTRICTS.

  The following requirements for side yards shall apply to every building in an RH-1(D) District. Any lot width of less than 33 feet as described herein shall refer only to substandard lots of record as defined in Section 180 of this Code.

  (a)   Minimum side yards shall be provided as follows:

     (1)   For lots with a width of less than 28 feet: none;

     (2)   For lots with a width of 28 feet or more but less than 31 feet: one side yard equal to the amount by which the lot width exceeds 25 feet, or the same total amount in the form of two side yards, one of which shall be at least three feet;

     (3)   For lots with a width of 31 feet or more but less than 40 feet: two side yards each of three feet;

     (4)   For lots with a width of 40 feet or more but less than 50 feet: two side yards each of four feet;

     (5)   For lots with a width of 50 feet or more: two side yards each of five feet.

  (b)   Where, however, the building does not exceed 25 feet in height, any side yard required by Subsection (a) to be more than three feet in width may be reduced to three feet if the width of the other side yard is increased by the same amount as the first one is reduced.

  (c)   Buildings may be built to the common line of two adjoining lots if a side yard having a width of not less than the combined width of the two side yards required above for each lot is provided on each such lot on the opposite side.

  (d)   Only those obstructions specified in Section 136 of this Code shall be permitted in a required side yard, and no other obstruction shall be constructed, placed or maintained within any such yard. No motor vehicle, trailer, boat or other vehicle shall be parked or stored within any such yard, except as specified in Section 136.

Check out more articles to see how the new bill, SB-9 help you add another unit or split the lot to add more value to the property.

If you're interested to see the ADU options for a specific address, order CityStructure ADU report. It helps you see and understand the size and location of a possible ADU for your lot which is the very fist step for any feasibility study. See what you could build, how much it may cost and what is the return on your investment. All in one ADU report.

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RH-2 Districts: Two-Family. ‍

These Districts are devoted to one-family and two-family houses, with the latter commonly consisting of two large flats, one occupied by the owner and the other available for rental. Structures are finely scaled and usually do not exceed 25 feet in width or 40 feet in height. Building styles are often more varied than in single-family areas, but certain streets and tracts are quite uniform. Considerable ground-level open space is available, and it frequently is private for each unit. The Districts may have easy access to shopping facilities and transit lines. In some cases, Group Housing and institutions are found in these areas, although nonresidential uses tend to be quite limited.‍

RH-3 Districts: Three-Family.

‍These Districts have many similarities to RH-2 Districts, but structures with three units are common in addition to one-family and two-family houses. The predominant form is large flats rather than apartments, with lots 25 feet wide, a fine or moderate scale and separate entrances for each unit. Building styles tend to be varied but complementary to one another. Outdoor space is available at ground level, and also on decks and balconies for individual units. Nonresidential uses are more common in these areas than in RH-2 Districts.

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RH-2, RH-3, RTO, RTO-M, RM-1 and RM-2 Districts, and the Pacific Avenue NC District.

The minimum rear yard depth shall be equal to 45% of the total depth of the lot on which the building is situated, except to the extent that a reduction in this requirement is permitted by subsection (e) below. Rear yards shall be provided at grade level and at each succeeding level or story of the building. In RH-2, RH-3, RTO, RTO-M, RM-1, and RM-2 Districts, exceptions are permitted on Corner Lots and through lots abutting a property with buildings fronting on both streets, as described in subsection (f) below.

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Reduction of Requirements in RH-2, RH-3, RTO, RTO-M, RM-1 and RM-2 Districts.

The rear yard requirement stated in subsection subsection2 (c)(3) above and as stated in subsection subsection2 (c)(2)(A) above for SRO buildings located in the Eastern Neighborhoods Mixed Use Districts not exceeding a height of 65 feet, shall be reduced in specific situations as described in this subsection (e), based upon conditions on adjacent lots. Except for those SRO buildings referenced above in this subsection (e) whose rear yard can be reduced in the circumstances described in subsection (e) to a 15-foot minimum, under no circumstances shall the minimum rear yard be thus reduced to less than a depth equal to 25% of the total depth of the lot on which the building is situated, or to less than 15 feet, whichever is greater.

Method of Measurement. For purposes of this subsection (e), an “adjacent building” shall mean a building on a lot adjoining the subject lot along a side lot line. In all cases the location of the rear building wall of an adjacent building shall be taken as the line of greatest depth of any portion of the adjacent building which occupies at least one-half the width between the side lot lines of the lot on which such adjacent building is located, and which has a height of at least 20 feet above grade, or two Stories, whichever is less, excluding all permitted obstructions listed for rear yards in Section 136 of this Code. Where a lot adjoining the subject lot is vacant, or contains no Dwelling or Group Housing structure, or is located in an RH-1(D), RH-1, RH-1(S), RM-3, RM-4, RC, RED, RED-MX, MUG, WMUG, MUR, UMU, SPD, RSD, SLR, SLI, SSO, NC, C, M, or P District, such adjoining lot shall, for purposes of the calculations in this subsection (e), be considered to have an adjacent building upon it whose rear building wall is at a depth equal to 75% of the total depth of the subject lot.

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Applicability to Special Lot Situations. In the following special lot situations, the general rule stated in subsection (e)(1) above shall be applied as provided in this subsection (e)(4), and the required rear yard shall be reduced if conditions on the adjacent lot or lots so indicate and if all other requirements of this Section 134 are met.

Lots Abutting Properties with Buildings that Front on Another Street or Alley. In the case of any lot that abuts along one of its side lot lines upon a lot with a building that fronts on another Street or Alley, the lot on which it so abuts shall be disregarded, and the forward edge of the required rear yard shall be reduced to a line on the subject lot which is at the depth of the rear building wall of the one adjacent building fronting on the same Street or Alley. In the case of any lot that abuts along both its side lot lines upon lots with buildings that front on another Street or Alley, both lots on which it so abuts shall be disregarded, and the minimum rear yard depth for the subject lot shall be equal to 25% of the total depth of the subject lot, or 15 feet, whichever is greater.

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Are you a prospective buyer or a real estate agent interested to see the development opportunities of any property? Here is how you can find out FREE ...

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