Bolthole Index

San Mateo County, California

Zoning, building permits and septic rules in Half Moon Bay, California

Half Moon Bay, California adopts and administers its own zoning under Title 18 of the city code, not San Mateo County's zoning1. The city takes building permit applications online or at City Hall2. Septic and well permits in San Mateo County come from the county's Environmental Health Services34. We could not confirm how the city applies septic rules inside city limits.

At a glance

Zoning
Half Moon Bay's own zoning ordinance, Title 18 of the city code1
Building permits
City of Half Moon Bay Community Development; online through Cloudpermit or at City Hall2
Septic and wells
San Mateo County Environmental Health Services issues the permits34
Minimum lot (R-1)
5,000 square feet of site area, with larger minimums in R-1-B-1 and R-1-B-2567
Height (R-1)
20 feet for one story, 28 feet for multi-story8
Manufactured homes
Allowed where a single-family detached home is allowed, with director approval in R-1 districts9
Floodplain
A city development permit is required inside mapped flood hazard areas10
Owner-builder
California's statewide owner-builder exemption covers licensing, not permits11

Who to call

Building permits

City of Half Moon Bay Community Development – Building Services

Building permit applications, plan check and inspections inside Half Moon Bay city limits

650-726-8270

[email protected]

501 Main St. Half Moon Bay, CA 94019

Online permits →

Zoning

City of Half Moon Bay Community Development – Planning Division

Zoning, planning permits and long-range planning inside Half Moon Bay city limits

650-726-8270

501 Main Street Half Moon Bay , CA 94019

Septic permits

San Mateo County Environmental Health Services

Septic (OWTS) permits, site evaluations and water-well drilling permits for San Mateo County

(650) 372-6200

Contact details are copied from each office’s official page and were checked against it on October 24, 2026.

Off-grid gear

Going off-grid in Half Moon Bay means bringing your own water and power. The kit we’d start with:

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Does Half Moon Bay have zoning, and what does it mean for lot size and setbacks?

Yes. Half Moon Bay adopts and administers its own zoning ordinance, Title 18 of the city code, and San Mateo County zoning does not govern land inside city limits1. The city's Planning Division reviews and decides planning permits12.

In the R-1 single-family district, the minimum site area is 5,000 square feet; R-1-B-1 requires 6,000 and R-1-B-2 requires 7,500567. R-1 setbacks are 20 feet front, 5 feet side, 15 feet on a street-facing side and 20 feet rear13. R-1-B-1 and R-1-B-2 require 25 feet in front14.

In the R-1 districts, single-story buildings top out at 20 feet and multi-story buildings at 28 feet8. Site coverage is capped at 50% for one story and 35% for multi-story, with a floor area ratio of 0.5:115. Substandard lots follow separate tables15. We have not summarized the commercial, mixed-use and open-space districts, so confirm your parcel's district with the Planning Division16.

Do you need a building permit in Half Moon Bay, and who issues it?

Inside Half Moon Bay, the city's own Community Development office handles building permits, not San Mateo County. The city is accepting permit applications online or in person2, and it uses the Cloudpermit platform for building permits and inspections2. Applications submitted from January 1, 2026 must conform to the 2025 California Building Standards Code17.

We could not confirm the city's list of work that is exempt from a building permit, so ask Building Services at 650-726-8270 before assuming a project is exempt2. California's owner-builder exemption removes the contractor-license requirement for qualifying owners; it does not itself eliminate a building-permit requirement11.

How do septic permits work in Half Moon Bay?

Septic permits are a county matter in San Mateo County, not a city one. Anyone installing an individual sewage disposal system in the county needs a permit from Environmental Health3, and Environmental Health observes and approves the work18. The county's only approved onsite system is a septic system, for areas without a municipal sewer19.

Whether a particular lot inside Half Moon Bay must connect to a public sewer, and how the city's sewer rules interact with the county's septic program, we could not confirm. Call San Mateo County Environmental Health Services at (650) 372-620020 before you count on a septic system. A new water well also needs a drilling permit from Environmental Health Services4.

Can you live in an RV or tiny home in Half Moon Bay?

We could not confirm a Half Moon Bay rule on living in an RV on private land. California's general rule is that RVs are not intended as permanent dwellings, and unless a local ordinance allows otherwise they may generally be occupied only in mobilehome parks or special occupancy parks21. Ask the Planning Division whether the city allows anything different.

For tiny homes, California requires that an occupied unit be approved as a recognized type, such as a manufactured home, a building-code home or an RV in an approved location; a unit that fits none of those is a noncomplying structure whose occupancy is illegal22. Manufactured homes are allowed wherever a single-family detached dwelling is permitted, but in R-1 districts the community development director must approve the home before building permits are issued9.

Building a home in Half Moon Bay: the steps, in order

  1. Confirm the zoning district and its lot, setback and height standards with the Planning Division1216.
  2. Check whether the parcel sits in a mapped flood hazard area; if so, a city development permit is required before construction begins10.
  3. If the lot has no municipal sewer or you need a well, contact San Mateo County Environmental Health Services about the permit320.
  4. Apply for the building permit through Cloudpermit or at City Hall2.
  5. Schedule inspections through Cloudpermit once the permit is issued2.

What stays with San Mateo County, and what to check before you buy in Half Moon Bay?

Septic and well permits stay with San Mateo County Environmental Health Services34. The county's building, zoning and driveway rules apply to unincorporated land only; for land outside the city, see the San Mateo County page.

County-level figures give context: the typical home value in San Mateo County is $1,595,76423, and the effective property tax rate is 0.6%24. Short-term vacation rentals in the city must be the operator's primary residence, so an investment property cannot count on that income25.

Watch-outs

  • Half Moon Bay's city-specific building permit exemptions, certificate of occupancy rules, permit fees and driveway requirements were not confirmed; ask Building Services at 650-726-82702.
  • Do not call the San Mateo County planning counter about a Half Moon Bay lot: the county's zoning information is provided only for unincorporated properties, and city limits are handled by the city's Planning Department26.
  • A lot in a FEMA special flood hazard area needs a city development permit before construction or other development begins10.

Sources

  1. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  2. City of Half Moon Bay Community Development – Building Services (halfmoonbay.gov)
  3. Land Use, Septic & Wells, quoted and re-checked
  4. Land Use, Septic & Wells, quoted and re-checked
  5. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  6. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  7. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  8. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  9. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  10. Chapter 14.34 Flood Damage Prevention, Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  11. Owner-Builder Overview, quoted and re-checked
  12. City of Half Moon Bay Community Development – Planning Division (halfmoonbay.gov)
  13. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  14. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  15. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  16. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  17. Approved Building Standards (California statewide rule), quoted and re-checked
  18. Land Use, Septic & Wells, quoted and re-checked
  19. Land Use, Septic & Wells, quoted and re-checked
  20. San Mateo County Environmental Health Services (smcgov.org)
  21. hcd.ca.gov (California statewide rule), quoted and re-checked
  22. Information Bulletin 2016-01: Tiny Homes (California statewide rule), quoted and re-checked
  23. Typical home value (Zillow): Bolthole Index county data
  24. Effective property tax rate: Bolthole Index county data
  25. Chapter 18.06 Residential Land Use (R-1, R-2, R-3), Half Moon Bay municipal code (eCode360) (Half Moon Bay), quoted and re-checked
  26. Get Zoning Information, quoted and re-checked

Written October 24, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Half Moon Bay

Half Moon Bay’s own rules

  • Local zoningPresent

    Land inside Half Moon Bay city limits; the city adopts and administers its own zoning ordinance (Title 18, Zoning).

    • Title 18 (Zoning) of the city code is the city's own zoning ordinance; county zoning does not govern land inside city limits.
    “the purpose of these residential district regulations is to: provide appropriately located areas for residential development that are consistent with the local coastal program, land use plan and general plan”
  • Zoning districtsPublished

    Residential zoning districts R-1, R-2, R-3 (and R-1-B-1, R-1-B-2, R-1-B-3 variants) inside Half Moon Bay city limits.

    • Commercial, mixed-use, open space and other districts are in other chapters of Title 18 and were not opened in this research pass.
    “table b of this chapter provides the schedule of development standards for all r-1 districts. table c provides the schedule of development standards for r-2 and r-3 districts.”
  • Minimum lot sizeSpecified

    R-1 single-family residential district (base district, Table B) inside Half Moon Bay city limits.

    • Table B calls this the minimum site area; substandard, severely substandard and exceptional lots follow Tables E and F and coastal development permit rules.
    • Site area is measured per the code's definitions, which were not opened.

    minimum site area: >= 5000 square feet

    “table b r-1 zoning district development standards building site characteristics r-1 r-1--b1 r-1--b2 minimum site area (square feet) 5,000 6,000 7,500”
    2 more reviewed findings on this topic
  • SetbacksSpecified

    R-1 single-family residential district inside Half Moon Bay city limits.

    • Combined side setbacks must equal at least 20% of average site width (Table B note 1).
    • Setbacks for substandard lots follow Table E and Table F.

    minimum front setback: >= 20 feet · minimum side setback: >= 5 feet · minimum street facing side setback: >= 15 feet · rear minimum setback: >= 20 feet

    “minimum front setback 20' 25' 25' minimum side setback 5' 5' 6' minimum street facing side setback 15' 15' 15' combined minimum side setback 1 20% 20% 20% rear, minimum setback 20' 20' 20'”
    One more reviewed finding on this topic
  • Lot coverageSpecified

    R-1, R-1-B-1 and R-1-B-2 single-family residential districts inside Half Moon Bay city limits.

    • Floor area ratio is 0.5:1 in all three columns of Table B.
    • Substandard lots follow Table E and Table F coverage and FAR rules.

    maximum single-story site coverage: <= 50 percent · maximum multi-story site coverage: <= 35 percent · floor area ratio: <= 0.5 ratio

    “maximum single-story site coverage 50% 50% 50% maximum multi-story site coverage 35% 35% 35% floor area ratio 0.5:1 0.5:1 0.5:1”
  • Building heightSpecified

    R-1 single-family residential district inside Half Moon Bay city limits.

    • Single-story structures above 20 feet must follow the height-exemption procedure (Table E/F note for substandard lots).

    single-story maximum height: <= 20 feet · multi-story maximum height: <= 28 feet

    “single-story, maximum height 20' 20' 20' multi-story, maximum height 28' 28' 28'”
  • Manufactured homesAllowed (with conditions)

    Manufactured homes on single-family residential sites inside Half Moon Bay city limits.

    • Community development director approval is required before building permits for an individual manufactured home in any R-1 district.
    • Must sit on a permanent foundation approved by the building official, with skirting, a roof pitch of at least 3 in 12, and finished floor no more than 20 inches above grade.
    • Must have been manufactured after June 15, 1976 and be certified under the National Manufactured Home Construction and Safety Act of 1974.
    • State registration must be canceled before occupancy.

    minimum width: >= 18 feet (measured at narrowest point) · maximum site slope: <= 10 percent (average slope of building site)

    “manufactured homes may be located in any residential district where a single-family detached dwelling is permitted, subject to the same restrictions on density and to the same property development regulations.”
  • Building in a floodplainRequired

    Construction or development inside an FEMA special flood hazard area (§ 14.34.070) in Half Moon Bay city limits.

    • The Director of Public Works administers the ordinance and grants or denies development permits (§ 14.34.140).
    • Development permits are required before construction or other development in mapped special flood hazard areas; construction standards are in §§ 14.34.170 onward.
    • Development outside mapped special flood hazard areas is not covered by this chapter.
    “a development permit shall be obtained before any construction or other development begins within any area of special flood hazard established in section 14.34.070.”
  • Short-term rentalsLimited

    Short-term vacation rentals inside Half Moon Bay city limits (Chapter 18.06 use regulations).

    • Short-term vacation rentals may not operate from mobile homes, recreational vehicles, multi-family developments with four or more units, mixed-use or residential developments with lower-income affordable units, farmworker housing, accessory dwelling units except pursuant to chapter 18.33, in OS-R or U-R districts, or in the substantially undeveloped planned developments.
    • No dwelling unit may be operated as a short-term vacation rental unless it is the primary residence of the operator.
    • In the commercial districts, only one unit in a duplex or triplex, or one unit in a mixed-use development, may be registered and operated for short-term vacation rental use.
    “b. primary residence. no dwelling unit shall be operated for short-term vacation rental use unless the dwelling is the primary residence of the operator.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Half Moon Bay or San Mateo County directly.

  • Building permit — Building permit requirement for a new home inside Half Moon Bay city limits.
  • Owner-builder exemption — Owner-builder exemption inside Half Moon Bay city limits.
  • Building code adopted — Building code adoption inside Half Moon Bay city limits.
  • Inspections — Building inspection requirement inside Half Moon Bay city limits.
  • Certificate of occupancy — Certificate of occupancy for a new home inside Half Moon Bay city limits.
15 more unanswered
  • Minimum dwelling size
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Subdividing land
  • Driveway access
  • Permit fees
  • Permit process

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Half Moon Bay publishes no rule on the point, not that none exists. San Mateo County’s page lists the county offices to call.

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