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Hillsborough, California: what can you build or do?

Plain-English answers to common homeowner questions, taken from Hillsborough's published ordinances, with every rule linked to the section it comes from.

Last reviewed 2026-10-05

• Accessory Dwelling Units (ADUs)
  Yes. ADUs are permitted on Hillsborough residential lots with an ADU permit and building permit, approved without a hearing within 60 days. A new detached ADU up to 800 sq ft and 16 ft tall with 4-foot side/rear setbacks qualifies under the state-standard track; larger units (up to 850 sq ft, or 1,000 sq ft with 2+ bedrooms) must meet extra local design standards.Allowed with a permit
• Backyard Chickens
  Yes, but only with a letter of permission from Hillsborough's city manager. Roosters three months or older are banned, and the coop or pen must be at least 125 feet from any neighbor's house.Allowed with a permit
• Short-Term Rentals (Airbnb / VRBO)
  No. Hillsborough treats rentals of fewer than 30 days as prohibited commercial "transitory lodging" in residential areas, and advertising them is also banned. You can rent your home, or a single room in the home you live in, for 30 days or longer.Not allowed
• Fences
  Fences along a street are normally limited to 6 feet, and up to 8 feet only with design review. Any fence in the street setback or over 6 feet needs design review, and any fence over 3 feet needs a building permit. Fences can't go in the town right-of-way, and corner lots must keep a 40-foot sight triangle clear above 2.5 feet.Allowed with board review
• Sheds & Accessory Buildings
  Sheds must normally meet Hillsborough's full setbacks: 25 feet from the street line and 20 feet from side and rear lot lines. One small shed (40 sq ft or less, 6 ft tall or less) may go in a setback if it's at least 5 feet from the lot line, 40 feet from any neighbor's house and the neighbor agrees in writing. All exterior construction needs design review.Allowed with board review
• Burn Permits & Backyard Fires
  Backyard brush and yard-waste burning isn't allowed: the Bay Area Air District's open-burning rule bans it, apart from narrow fire-hazard burns approved by a fire official. Recreational fires in a fire pit using clean dry wood, and cooking fires, are allowed except during Mandatory Burn Ban periods declared by the air district (Spare the Air alerts).Restricted
• Home-Based Businesses
  Yes, with an annual Hillsborough home business permit from the Finance Department. The business must be run entirely inside the home, with no signs and no more traffic or parking than a normal household.Allowed with a permit
• Swimming Pools
  Yes, with a building permit. Pools, spas and hot tubs normally must be 20 feet from side and rear lot lines and 25 feet from the street, but can be as close as 5 feet to a side or rear line if they're 40 feet from the neighbor's house and the neighbor agrees in writing. A safety barrier and at least two state drowning-prevention features are required.Allowed with a permit
• Building Near the Coast or Creeks
  Hillsborough has no coastal or creek-setback zone in its code; building near a creek is governed by the town's floodplain rules. In a FEMA-mapped flood hazard area you need a floodplain development permit, the lowest floor must be at least 1 foot above base flood elevation, and building in a floodway is barred unless an engineer shows no rise in flood levels.Allowed with a permit
• Docks, Piers & Floats
  Hillsborough's municipal code chapters we reviewed don't regulate docks, piers or floats. The town has no harbor, bay frontage or lake shoreline in its code, and no dock permit process.Not specifically regulated