Bolthole Index

Napa County, California

Building permits, zoning and septic rules in St. Helena, California

St. Helena, California requires a city building permit before construction begins, with plans reviewed by the city Building Department.1 St. Helena administers its own zoning, while Napa County Environmental Health regulates septic systems on city parcels not served by public sewer.23 Apply for city building permits and schedule inspections through eTRAKiT.4

At a glance

Building permits
City Building Department; construction starts after issuance1
Zoning
City zoning applies inside St. Helena2
Septic permits
Napa County Environmental Health for city parcels without public sewer; new installations require review, an installation permit and inspections35
Minimum lot area
LR-1A: 1 acre, with a qualifying lot-line-adjustment exception; LR: 7,000 square feet, with separate small-lot standards67
Manufactured homes
Qualifying homes require a permanent foundation and conventional-dwelling zoning compliance8
Accessory dwellings
ADUs are contemplated in LR-1A and MR; ask city Planning for complete approval standards910

Who to call

Building permits

City of St. Helena Building Department

City building plan review, building permit issuance and construction inspections

707-967-2779

1088 College Ave. St. Helena, CA 94574

Online permits →

Building permits

St. Helena Building Division — online applications and inspections

eTRAKiT building applications, electronic plans, payments and inspection scheduling

707-967-2779

[email protected]

1088 College Avenue St. Helena, CA 94574

Online permits →

Planning & zoning

St. Helena Planning Division

City zoning, subdivision review and planning applications

(707) 968-2740

1088 College Avenue St. Helena, CA 94574

Septic permits

Napa County Environmental Health — Well and Onsite Wastewater Treatment

Septic regulation for city parcels without public sewer; county well permit inquiries

707-253-4417

[email protected]

1195 Third Street, 2nd Floor Napa CA 94559

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Off-grid gear

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

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Do you need a building permit in St. Helena, CA?

St. Helena’s Building Department says construction may begin only after the building permit is issued; city plan review evaluates structural integrity, construction details, and fire and life safety requirements.1 St. Helena’s building permit cost depends on project valuation, the area involved and, for some projects, impact fees; plan-check fees are paid at application and remaining fees at issuance.1 Ask the city Building Department which building permit and supporting plans your specific house, addition or repair needs before commissioning the final design.1

Who handles St. Helena building permits and zoning applications?

Reach St. Helena’s Building Division at 707-967-2779 or [email protected] for electronic building applications and inspection scheduling.4 St. Helena’s eTRAKiT portal accepts building applications, electronic plans, fee payments and inspection requests; the city no longer accepts paper applications and plans.4 For zoning and subdivision questions, contact St. Helena’s Planning Division at (707) 968-2740 at 1088 College Avenue St. Helena, CA 94574.10 City Planning encourages a staff meeting before a planning application so staff can explain regulations, application forms and the review schedule.10

Does St. Helena have zoning, minimum lot sizes and height limits?

St. Helena has its own zoning code, with residential districts including LR-1A, LR, MR and HR.211 In St. Helena’s LR-1A district, minimum lot area is 1 acre; a qualifying lot-line adjustment may create smaller parcels without increasing the parcel count, but no resulting lot may be below 7,000 square feet.6 St. Helena’s LR district lists a 7,000-square-foot minimum, with a separate small-lot-development provision.7

St. Helena’s LR-1A lot coverage limit is 35%, including accessory structures, and principal structures have a 30-foot height limit.1213 Treat lot area, coverage and height as separate design constraints: ask city Planning to confirm the parcel’s district and applicable setbacks before placing a home on a site plan.101

How do septic permits work inside St. Helena?

Napa County Environmental Health regulates septic systems on St. Helena parcels not served by public sewer.3 New residential septic installations covered by Napa County’s program require plan review, an installation permit and construction inspections.514 Contact the county’s Well and Onsite Wastewater Treatment office at 707-253-4417 to discuss a city parcel without sewer service.15

City building approval and county septic approval address different parts of a St. Helena project: the city reviews building plans, while county Environmental Health regulates the onsite wastewater system.13 St. Helena Public Works reviews water and wastewater connections during the city building review, so ask about service availability before choosing an onsite system.1

Can you live in an RV, tiny home or manufactured home in St. Helena?

We could not confirm St. Helena’s private-lot RV occupancy, temporary camping or wheeled tiny-home rules; ask the city Planning Division about the proposed use and address before arranging to live on the land.10 St. Helena’s qualifying manufactured-home provisions require a permanent foundation, single-family residential use and compliance with zoning provisions for conventionally built dwellings, along with certification and exterior-material conditions.8

St. Helena’s LR-1A and MR district descriptions contemplate accessory dwelling units, but those descriptions do not establish the complete approval requirements for a particular project.9 Ask city Planning whether the proposed small dwelling can qualify as an ADU and which development and design standards apply.910

What are the steps to build a home in St. Helena?

  1. Meet with St. Helena Planning to confirm the proposed use, building size, height and location against city zoning before finalizing plans.101
  2. Discuss water and wastewater connections through city Public Works review; if the parcel has no public sewer, bring the septic proposal to Napa County Environmental Health for plan review and an installation permit.135
  3. Create a city eTRAKiT account, submit the building application and electronic plans, and pay the applicable fees.4
  4. Wait for city building permit issuance before beginning construction, then request city construction inspections through eTRAKiT and complete required county septic inspections.1414

What should you check before buying land in St. Helena?

For a St. Helena parcel, ask city Planning about the proposed residential use and any subdivision plan: St. Helena regulates subdivisions, and residential development standards differ by district.101611 California requires local authorization before constructing, modifying or destroying a water well; we could not confirm St. Helena’s additional city well requirements, so ask city Planning and Napa County Well and Onsite Wastewater Treatment about both approvals.171015

A St. Helena address should not substitute for confirming city limits: the county’s building and zoning rules discussed on the Napa County guide apply to unincorporated land.1819 If rental income is part of the purchase plan, St. Helena requires a short-term rental permit and caps the citywide total at 25; a permit is not transferable.20

Watch-outs

  • St. Helena requires inspection requests through eTRAKiT and no longer accepts paper building applications or plans.4
  • We could not confirm St. Helena’s RV occupancy, temporary camping, tiny-home occupancy or minimum dwelling-size rules; ask city Planning before committing to those uses.10
  • Napa County septic regulation reaches St. Helena parcels without public sewer, even though city offices review building permits and zoning.3110

Sources

  1. City of St. Helena Building Department (cityofsthelena.gov)
  2. Title 17 Zoning Code (St. Helena), quoted and re-checked
  3. Well and Onsite Wastewater Treatment, quoted and re-checked
  4. St. Helena Building Division — online applications and inspections (cityofsthelena.gov)
  5. Well and Onsite Wastewater Treatment, quoted and re-checked
  6. cityofsthelena.gov (St. Helena), quoted and re-checked
  7. 17.16.030 Development standards (St. Helena), quoted and re-checked
  8. 17.22.160 Mobile homes (St. Helena), quoted and re-checked
  9. cityofsthelena.gov (St. Helena), quoted and re-checked
  10. St. Helena Planning Division (cityofsthelena.gov)
  11. Title 17 Zoning Code (St. Helena), quoted and re-checked
  12. cityofsthelena.gov (St. Helena), quoted and re-checked
  13. cityofsthelena.gov (St. Helena), quoted and re-checked
  14. LAMP Additional Considerations AB 885, quoted and re-checked
  15. Napa County Environmental Health — Well and Onsite Wastewater Treatment (napacounty.gov)
  16. Title 16 Subdivisions (St. Helena), quoted and re-checked
  17. Well Standards (California statewide rule), quoted and re-checked
  18. Code Compliance Frequently Asked Questions (2026 county census)
  19. Code Compliance (2026 county census)
  20. 17.22.200 Short-term rentals (St. Helena), quoted and re-checked

Written October 11, 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 St. Helena

St. Helena’s own rules

  • Local zoningPresent

    Land inside St. Helena city limits.

    • The city code contains a Title 17 Zoning Code with residential, agricultural and natural-resource, use-specific, and citywide standards divisions.
    “City of St. Helena Municipal Code Title 17, Zoning Code”
  • Zoning districtsPublished

    Zoning districts inside St. Helena city limits.

    • The code publishes residential, commercial/mixed-use, business/industrial, community agricultural/natural-resource, public/open-space, overlay, and use-specific zoning chapters.
    “Table 17.15.020.A: Base Zoning Districts Abbreviation Name LR-1A Low Density Residential One-Acre Minimum LR Low Density Residential MR Medium Density Residential HR High Density Residential”
  • Minimum lot sizeSpecified

    LR-1A Low Density Residential One-Acre Minimum district inside St. Helena city limits.

    • Parcels created by lot-line adjustments may be less than one acre if the number of parcels does not increase and no lot is less than 7,000 square feet.

    minimum lot area: 1 acre (Subject to the lot-line-adjustment exception stated in End Note 3.) · minimum lot area: >= 7000 sq ft (No lot created by qualifying lot-line adjustment may be smaller.)

    “Min. Lot Area 1.0 ac 3 7,000 sq ft 6,000 sq ft 7,000 sq ft”
    One more reviewed finding on this topic
    • Specified — LR Low Density Residential district inside St. Helena city limits.
      “Min. Lot Area 1.0 ac 3 7,000 sq ft 6,000 sq ft 7,000 sq ft”
  • Lot coverageSpecified

    LR Low Density Residential district inside St. Helena city limits.

    • Lot coverage includes accessory structures.
    • New small lot development has a separate 55 percent figure in the table.

    maximum lot coverage: <= 35 percent (55% for new small lot development.)

    “Max. Lot Coverage (includes accessory structures) 35% 35% [...] 55% for new small lot development”
    One more reviewed finding on this topic
    • Specified — LR-1A district inside St. Helena city limits.
      “Max. Lot Coverage (includes accessory structures) 35% 35%”
  • Building heightSpecified

    LR Low Density Residential district inside St. Helena city limits.

    • The table limits principal structures to two stories and includes a separate accessory-structure height.

    principal structure maximum height: <= 30 ft (Two-story limit.) · accessory structure maximum height: <= 16 ft

    “Principal Structure 30 ft 30 ft/2 stories 30 ft/2 stories 42 ft/3 stories [...] Accessory Structure 6 16 ft 16 ft 16 ft 16 ft”
    One more reviewed finding on this topic
    • Specified — LR-1A district inside St. Helena city limits.
      “Principal Structure 30 ft 30 ft/2 stories 30 ft/2 stories 42 ft/3 stories [...] Accessory Structure 6 16 ft 16 ft 16 ft 16 ft”
  • Manufactured homesLimited

    Installation and occupancy of qualifying mobile/manufactured homes inside St. Helena city limits.

    • The home must have been constructed and/or purchased after October 1976.
    • It must be certified under the National Mobile Home Construction of Safety Standards Act of 1974.
    • It must be installed on a foundation system pursuant to Health and Safety Code Section 18551.
    • It may be occupied only as a single-family residential use.
    • It is subject to zoning provisions applicable to conventionally built dwellings.
    • It must be attached to a permanent foundation complying with applicable building regulations.
    • Exterior and roof materials must satisfy the listed conventional-dwelling requirements.

    construction/purchase date threshold: > October 1976

    “The installation of mobile homes constructed and/or purchased after October 1976, and certified under the National Mobile Home Construction of Safety Standards Act of 1974 (42 U.S.C. § 5401 et seq.) on a foundation system pursuant to § 18551 of the Health and Safety Code must be permitted in accordance with the following conditions: A. To be occupied only as a single-family residential use.”
  • Accessory dwellingsAllowed (with conditions)

    Accessory dwelling units in the LR-1A and MR residential zoning districts inside St. Helena city limits.

    • The applicable zoning, development, and design standards remain applicable.
    • The source identifies ADUs as a permitted residential use concept but does not provide the complete approval standards in the opened excerpt.
    “The LR-1A Zone provides for single-family detached homes, accessory dwelling units, limited agricultural uses, and compatible uses. [...] The MR Zone is intended to protect existing patterns of development for a range of residential development types, accessory dwelling units, and compatible uses in areas.”
  • Subdividing landRegulated (with conditions)

    Subdivision, parcel maps, tentative maps, final maps, urban lot splits, and related improvements inside St. Helena city limits.

    • The municipal code contains separate provisions for subdivision maps, conceptual maps, tentative maps, final maps, parcel maps, urban lot splits, dedications, fees, reservations, and design standards.
    “TENTATIVE SUBDIVISION MAP or VESTING TENTATIVE SUBDIVISION MAP - Plans shall be prepared in compliance with the requirements of the Subdivision Map Act (St. Helena Municipal Code Section 16.16.020 & Section 16.16.030) and accompanied by all required information.”
  • Short-term rentalsLimited

    Short-term rental use of single-family dwellings on parcels in St. Helena city limits.

    • A short-term rental permit is required.
    • The use must be permitted in the applicable zoning district.
    • No more than one single-family dwelling per lot may be used.
    • The permit holder must own the property, may hold no more than one permit, and the permit is not transferable.
    • The dwelling must exist or be constructed as of the application date.
    • The citywide total may not exceed 25 permits.
    • The dwelling may have no more than five bedrooms used for short-term rental and occupancy is limited to two times the bedrooms plus two, up to 12 persons.
    • At least two on-site parking spaces are required.
    • The dwelling must meet building, health, fire, and related safety codes and receive fire-department inspection before short-term-rental activity begins.

    citywide permit cap: <= 25 permits (At any time.) · maximum bedrooms used for short-term rental: <= 5 bedrooms · maximum guests: <= 12 persons (Also limited to two times the number of bedrooms plus two.) · minimum on-site parking: >= 2 spaces

    “The total number of permits for short-term rental dwellings in the City must not exceed 25 at any time. [...] The maximum number of bedrooms used for short-term rental use in the short-term rental dwelling must be no greater than five.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask St. Helena or Napa County directly.

  • Building permit — New construction and other building work inside St. Helena city limits.
  • Owner-builder exemption — Owner-builders performing construction inside St. Helena city limits.
  • Inspections — Building work inside St. Helena city limits.
  • Certificate of occupancy — Occupancy of buildings inside St. Helena city limits.
  • Minimum dwelling size — Minimum dwelling size in LR-1A and LR districts inside St. Helena city limits.
14 more unanswered
  • 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
  • Driveway access
  • Building in a floodplain
  • 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 St. Helena publishes no rule on the point, not that none exists. Napa County’s page lists the county offices to call.

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