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San Marcos · Building on your lot

Sheds, garages and other accessory structures in San Marcos

Accessory structures are limited to 1 story and 15 feet, and may be no higher than the main home (city rule).

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Key points

  • Accessory height: Accessory structures are limited to 1 story and 15 feet, and may be no higher than the main home (city rule).

Each rule below links to the section of the San Marcos Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What San Marcos's code says

San Marcos code What San Marcos's code adds
Maximum height
  • No more than 1 story and 15 feet at the roof peak.
    Also no higher than the main home. Does not apply to ADUs.
    § 20.410.040 · code text
    Height of the accessory structure(s) shall be one (1) story maximum, up to a maximum of fifteen (15) feet at peak of roof, and shall not exceed the height of the primary dwelling unit.
Size or lot coverage
  • No more than 40% of the main home's living area or 800 square feet, whichever is less.
    Applies: All fully enclosed accessory structures with an existing single-family home, not counting ADUs.
    § 20.410.040 · code text
    The maximum allowable gross floor area for all completely enclosed accessory structures in conjunction with an existing single-family residence, excluding ADUs, shall be equal to forty percent (40%) of the living area of the primary dwelling unit, or eight hundred (800) square feet of gross floor area, whichever is less.
Side and rear setback
  • At least 5 feet from the rear property line.
    Applies: Rear property line setback.
    § 20.410.040 · code text
    Rear property line setback: minimum five (5)-foot setback required.
  • At least 5 feet from the interior property line.
    Applies: Accessory structures behind the main building, in the rear yard area.
    § 20.410.040 · code text
    If located behind the primary building, minimum of five (5)-foot setback to interior property line shall be permitted in the rear yard area.
Distance from the house
  • At least 10 feet from the main home or any other accessory structure.
    Applies: Detached accessory structures.
    § 20.410.040 · code text
    If detached, a minimum of ten (10) feet separation from the primary dwelling unit or any other accessory structure.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How big can a shed or accessory building be in San Marcos?

Accessory structures are limited to 1 story and 15 feet, and may be no higher than the main home (city rule).

General information, not legal advice.

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San Marcos Municipal Code — full text