Portola Valley · Building on your lot
Building on your lot in Portola Valley
Portola Valley's fence rules cover horse fences and permits for fences in required yards. Accessory structures fall under their own chapter.
Key points
- Fences: Fences in required yards need a permit, except those at most 2 feet tall and 20 feet long; horse fences, at most 4 feet.
- Accessory structures: Portola Valley has a chapter on accessory structures (Chapter 18.42).
Each rule below is marked Portola Valley code or CA state law and links to the section it comes from (checked October 2026). General information, not legal advice.
Fences and walls
| Height anywhere on the lot |
|
|---|---|
| Permit |
|
Lot splits under SB 9
Portola Valley code 2 parcels of about equal area; neither may be smaller than 40% of the original lot. No new parcel may be smaller than 1,200 square feet.
All 18 Portola Valley rules on lot splits under SB 9, with the code text →
Solar panels and EV chargers
Portola Valley code The building official issues all needed permits when the application is complete and meets the town's checklist. Electronic submittal is allowed, and electronic signatures are accepted.
All 6 Portola Valley rules on solar panels and EV chargers, with the code text →
Tree removal
| Permit to remove |
|
|---|
Building in a flood zone
| Floodplain permit |
|
|---|---|
| Height of the lowest floor |
|
Noise and construction hours
Portola Valley code Leaf blowers at most 65 dBA at 50 feet, labeled 65 dBA or less, with mufflers and full extension tubes. 65 dBA Lmax.
All 5 Portola Valley rules on noise and construction hours, with the code text →
Family child care homes
| Zoning | A small or large family child care home is a residential use and a use by right under all local ordinances, including zoning |
|---|---|
| Business license or fee | A city or county may not charge a business license, fee or tax to run a family child care home |
| Local rules | Local limits on height, setbacks, lot size, health and safety must be the same as for every other home in the same zone |
| Small home | Up to eight children, counting the provider's own children under 10 who live there |
| Large home | 7 to 14 children, counting the provider's own children under 10 who live there |
Parking spaces required for homes
Portola Valley code 2 guest parking spaces in addition to the required spaces. 1 space for every 3 units or fraction thereof.
All 6 Portola Valley rules on parking spaces required for homes, with the code text →
Other Portola Valley rules on this
Portola Valley's code also has these chapters. We have not summarized their values on this page yet; read them in the library.
- Accessory structures (Ch. 18.42)
- Fences for horses (§ 18.43.060)
- Horsekeeping permits and stables (Ch. 6.08)
- Erosion control on graded slopes (§ 15.12.260)
- Grading in creek setbacks (§ 18.59.110) — creek setback areas only
Who this affects
Frequently asked questions
How tall can a fence be in Portola Valley?
Fences in required yards need a permit, except those at most 2 feet tall and 20 feet long; horse fences, at most 4 feet.
How big can a shed or accessory building be in Portola Valley?
Portola Valley has a chapter on accessory structures (Chapter 18.42). Portola Valley also has a related rule: Accessory structures (Ch. 18.42).
Do I need a permit to remove a tree in Portola Valley?
Portola Valley's code: Yes. A site development permit is required. (Removing or harming a significant tree, including placing fill within the dripline or greatly reducing the tree's size.) (§ 15.12.070).
What are the rules for building in a Portola Valley flood zone?
Portola Valley's code: A development permit is needed before any construction or other development begins in a special flood hazard area. (§ 18.32.035); At or above the regulatory base flood elevation. (New or substantially improved homes; the lowest floor includes any basement.) (§ 18.32.060).
Can I run a family child care home in Portola Valley?
California law sets this for every city, including Portola Valley: Zoning: A small or large family child care home is a residential use and a use by right under all local ordinances, including zoning (Health & Safety Code § 1597.45(a)); Business license or fee: A city or county may not charge a business license, fee or tax to run a family child care home (Health & Safety Code § 1597.45(b)); Local rules: Local limits on height, setbacks, lot size, health and safety must be the same as for every other home in the same zone (Health & Safety Code § 1597.45(e)); Small home: Up to eight children, counting the provider's own children under 10 who live there (Health & Safety Code § 1596.78(c)); Large home: 7 to 14 children, counting the provider's own children under 10 who live there (Health & Safety Code § 1596.78(b)).
General information, not legal advice.
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