Bolthole Index

Contra Costa County, California

Building permits, zoning and land rules in Hercules, California

Hercules, California requires building permits for regulated construction, with necessary approvals from the county building official.1 Hercules controls zoning and residential land-use review; Contra Costa Health handles septic systems and wells in Contra Costa County.234 Sewer availability limits onsite sewage disposal inside Hercules, so an off-grid plan needs more than zoning approval.5

At a glance

Building permits
Required for regulated construction; start with the Hercules Building Division1
Zoning
City zoning applies, with residential use-permit and design-review requirements23
Septic systems
Contra Costa Health review; city sewer access limits onsite disposal45
Accessory dwellings
Allowed in the listed residential districts; building permits and city review still required67
Lot size
RS-L minimum is 6,000 square feet, with an approved planned-development exception8
Water wells
Environmental Health issues well permits and inspects drilling4

Who to call

Building permits

Hercules Building Division

Building permit questions and inspection coordination for Hercules

510-799-8244

111 Civic Drive, Hercules, CA 94547

Zoning

Hercules Community Development Department

City zoning, use permits and development standards

(510) 799-8200

111 Civic Drive, Hercules, CA 94547

Building permits

Hercules Community Development Department — ADU review

ADU building permit review and city approval for county plan preapproval

Septic permits

Contra Costa Health — Environmental Health Land Use Program

Septic plan review, construction review, well permits and drilling inspections

925-608-5500

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 Hercules means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Hercules, CA?

Hercules requires approval from the county building official before regulated construction, alteration, repair, conversion or demolition begins.1 Electrical, plumbing and mechanical work also requires a building permit.1 Contact the Hercules Building Division about the proposed scope before treating a small project as exempt; the division provides clarification for remodels and additions.1 A building permit also brings an inspection requirement, so include inspection coordination in the construction schedule.1

Who handles Hercules building permits and zoning questions?

Start building permit questions with the Hercules Building Division at 510-799-8244; the municipal office is at 111 Civic Drive, Hercules, CA 94547.1 Hercules receives building inspection services from Contra Costa County, while city planning approval comes first for ADU plans submitted for county preapproval.7 For zoning, land use, use permits and development standards, contact the Hercules Community Development Department through the city number, (510) 799-8200.9 Septic and well questions belong with Contra Costa Health Environmental Health, rather than the city zoning counter.4

Does Hercules have zoning, lot-size limits and setbacks?

Hercules has its own zoning ordinance, and residential development is subject to district-specific standards.210 In RS-L, the minimum lot size is 6,000 square feet unless an approved planned development allows a smaller lot.8 RS-L setbacks are 20 feet front, 15 feet rear, 5 feet side and 15 feet corner-side; an approved planned development may allow a smaller side setback.11 RS-E setbacks are 20 feet front, 25 feet rear, 15 feet side and 20 feet corner-side.12 Maximum site coverage differs too: 20% in RS-E and 50% in RS-L.1314 Ask Community Development to identify the parcel’s district and applicable development standards before sizing a house or dividing land.915

How do septic permits and sewer connections work in Hercules?

Hercules allows domestic sewage disposal facilities where a property lacks access to the city public sanitary sewer or the sewer is not within 200 feet of the exterior property boundary.5 When sewer access becomes available within that distance, the owner must connect within 90 days after notice.5 That conditional allowance does not establish permission for every off-grid sanitation method.5 Contra Costa Health’s Land Use Program reviews septic designs and inspects construction, and Environmental Health reviews building plans on septic properties.4 The county health program lists site and soil evaluation, percolation testing, system design and a construction permit as separate application steps, with monitoring for an alternative system.4

Can you live in an RV or tiny home on land in Hercules?

We could not confirm a Hercules rule allowing RV occupancy, temporary camping or a tiny home used as a dwelling; ask Community Development about the proposed use and parcel before buying for that purpose.9 Hercules does allow accessory dwelling units in RS-E, RS-L, RM-L, RM-M and RM-H residential districts, subject to other applicable requirements.6 An ADU or junior ADU needs a building permit and Community Development review.7 Treat the ADU pathway as a separate question from permission to occupy a vehicle, and have the city identify the approvals for the actual dwelling proposed.97

What are the steps to building a home in Hercules?

Start with Hercules Community Development to identify zoning and development standards for the parcel.9 New and expanded residential development must apply for an administrative or conditional use permit; administrative review of new single-family homes, additions and remodels is limited to conformance with development regulations.3 New and expanded development other than additions and remodels also requires design review.3 Resolve sewer availability next, and involve Environmental Health in septic building-plan review where applicable.54 Obtain the required building permit before regulated work and arrange building inspections.1 For a mapped special flood-hazard overlay parcel, ask city planning about the additional Flood Damage Prevention Ordinance applications and approvals.16

What should you check before buying land in Hercules?

Ask Hercules Community Development to confirm the parcel’s district, proposed residential use and subdivision approvals rather than assuming an existing lot can accommodate the planned project.915 Verify whether sewer access triggers the city’s connection requirement before budgeting for septic.5 For a private well, Contra Costa Health reviews the design, issues the well permit and inspects drilling.4 We could not confirm Hercules-specific owner-builder conditions, minimum dwelling floor area or project fee amounts; ask the Building Division and Community Development for the requirements for the proposed project.19 For land outside Hercules city limits, use the Contra Costa County guide, because the county’s zoning information covers unincorporated areas.17

Watch-outs

  • Hercules sewer access can make connection mandatory within 90 days after notice, even where onsite sewage disposal was previously possible.5
  • A Hercules parcel in the special flood-hazard overlay has additional flood-prevention application and permit requirements.16
  • We could not confirm RV or tiny-home occupancy permission in Hercules; get a parcel-specific answer from Community Development before committing to that use.9

Sources

  1. Hercules Building Division (herculesca.gov)
  2. City of Hercules Municipal Code (Hercules), quoted and re-checked
  3. Chapter 13-6: Residential Districts (Hercules), quoted and re-checked
  4. Contra Costa Health — Environmental Health Land Use Program (cchealth.org)
  5. Chapter 4: Sanitary Sewers (Hercules), quoted and re-checked
  6. Chapter 13-6: Residential Districts (Hercules), quoted and re-checked
  7. Hercules Community Development Department — ADU review (herculesca.gov)
  8. Chapter 13-6: Residential Districts (Hercules), quoted and re-checked
  9. Hercules Community Development Department (herculesca.gov)
  10. City of Hercules Municipal Code (Hercules), quoted and re-checked
  11. Chapter 13-6: Residential Districts (Hercules), quoted and re-checked
  12. Chapter 13-6: Residential Districts (Hercules), quoted and re-checked
  13. Chapter 13-6: Residential Districts (Hercules), quoted and re-checked
  14. Chapter 13-6: Residential Districts (Hercules), quoted and re-checked
  15. Chapter 2: Subdivisions (Hercules), quoted and re-checked
  16. City of Hercules Municipal Code (Hercules), quoted and re-checked
  17. Planning and Zoning, 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 Hercules

Hercules’s own rules

  • Local zoningPresent

    Land inside Hercules city limits.

    • The City publishes a Title 13 Zoning Ordinance containing zone-district regulations, property-development standards, land-use requirements, and administration provisions.
    “Title 13 Zoning Ordinance (Sec. 13-1.100 – Sec. 13-60.200)”
  • Zoning districtsPublished

    Zoning districts inside Hercules city limits.

    • The municipal zoning ordinance publishes residential, mobile-home-park, commercial, industrial, public/quasi-public, mixed-use, overlay, and specific-plan districts.
    “Division II ZONE DISTRICT REGULATIONS [...] Chapter 13-6 RESIDENTIAL DISTRICTS [...] Chapter 13-7 P-M-H MOBILE HOME PARK DISTRICT [...] Chapter 13-8 COMMERCIAL DISTRICTS [...] Chapter 13-9 INDUSTRIAL DISTRICT [...] Chapter 13-10 PUBLIC/QUASI-PUBLIC DISTRICT”
  • Accessory dwellingsAllowed

    Accessory dwelling units in the RS-E, RS-L, RM-L, RM-M, and RM-H residential districts inside Hercules city limits.

    • Table 13-6.1 marks Accessory Dwelling Unit as P in all five listed residential districts.
    • Other applicable development, building, and state-law requirements may apply.
    “Accessory Dwelling Unit P P P P P Section 13-35.320”
  • Off-grid sanitationLimited

    Domestic sewage disposal on property inside Hercules city limits.

    • Allowed only where there is no access to the City's public sanitary sewer or the sewer is not within 200 feet of the exterior property boundary.
    • Connection becomes mandatory within 90 days after notice when sewer access becomes available within 200 feet.
    • The code does not establish that all off-grid sanitation methods are allowed.

    sewer distance threshold: > 200 feet (Exterior property boundary)

    “Facilities for the disposal of domestic sewage may be maintained on property that does not have access to the public sanitary sewer of the City and on property where the public sanitary sewer of the City is not within two hundred (200) feet of the exterior boundary of the property; provided, that when access to the public sanitary sewer of the City becomes available to the property and is within two hundred (200) feet of the exterior boundary of the property, the owner of such property shall connect to the public sanitary sewer of the City within ninety (90) days after date of notice to do so;”
  • Subdividing landRegulated (with conditions)

    Subdivision, parcel maps, final maps, and urban lot splits inside Hercules city limits.

    • The municipal code contains subdivision requirements and separate approval-process provisions for final maps, parcel maps, and urban lot splits.
    “Article 4 Final Map [...] Article 5 Parcel Map [...] Article 6 Subdivision Requirements [...] Article 9 Urban Lot Splits [...] Sec. 10-2.906 Approval Process.”
  • Permit processPartial

    New and expanded residential development inside Hercules city limits.

    • All new and expanded residential development must apply for an administrative or conditional use permit.
    • Administrative-use-permit review of new single-family homes, additions, and remodels is limited to conformance with development regulations.
    • All new and expanded development except additions and remodels is subject to design review.
    “All new and expanded residential development shall apply for an administrative or conditional use permit. Administrative use permit review of new single-family homes, additions and remodels shall be limited to conformance with development regulations specified or referenced within this Chapter. [...] All new and expanded development except for additions and remodels shall also be subject to Chapter 13-42, Design Review.”

Rules another office applies inside Hercules

Hercules does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum lot sizeSpecified

    RS-E Residential Single-Family Estate district inside Hercules city limits.

    • The zoning map designates the applicable density and corresponding minimum lot size.
    • For 1 or 2 units per acre density, the corresponding minimum lot size is 1 acre or 0.5 acre.

    minimum lot size: 1/2 acre (Zoning-map designation may require 1 acre for 1 unit per acre density.)

    “Maximum density and minimum lot size as designated on zoning map for 1 or 2 units per acre density and corresponding 1 acre or 0.5 acre minimum lot size.”
    One more reviewed finding on this topic
    • Specified — RS-L Residential Single-Family Low Density district inside Hercules city limits.
      “RS-L Residential Single-Family Low Density. To provide areas for single-family housing on smaller lots that will generally be developed as part of a larger planned subdivision where a limited number of models of varied exterior designs are built in a random pattern on individual lots with a gross density of 2 to 7 units per acre and a minimum parcel size of 6,000 square feet unless a smaller lot size is allowed by an approved planned development (PD).”
  • SetbacksSpecified

    RS-L Residential Single-Family Low Density district inside Hercules city limits.

    • The side setback is a minimum unless a smaller setback is allowed by an approved planned development plan.
    • Table 13-6.2 states that regulation standards are minimum amounts unless otherwise stated.

    front setback: >= 20 feet · rear setback: >= 15 feet · side setback: >= 5 feet (Smaller setback may be allowed by an approved planned development plan.) · corner-side setback: >= 15 feet

    “Setbacks Front (ft) 20 20 15 15 15 Rear (ft) 25 15 15 15 15 Side (ft) 15 5 15(6) 15(6) 15(6) Corner Side (ft) 20 15 15 15 15”
    One more reviewed finding on this topic
    • Specified — RS-E Residential Single-Family Estate district inside Hercules city limits.
      “Setbacks Front (ft) 20 20 15 15 15 Rear (ft) 25 15 15 15 15 Side (ft) 15 5 15(6) 15(6) 15(6) Corner Side (ft) 20 15 15 15 15”
  • Lot coverageSpecified

    RS-E Residential Single-Family Estate district inside Hercules city limits.

    • Table 13-6.2 states that regulation standards are minimum amounts unless otherwise stated.

    maximum site coverage: <= 20 percent

    “Maximum Site Coverage 20% 50% 60% 60% 60%”
    One more reviewed finding on this topic
    • Specified — RS-L Residential Single-Family Low Density district inside Hercules city limits.
      “Maximum Site Coverage 20% 50% 60% 60% 60%”
  • Building heightSpecified

    RS-E Residential Single-Family Estate district inside Hercules city limits.

    • Height limits are identified within each zoning district's property-development regulations.

    maximum building height: <= 35 feet (Certain structures may exceed the district limit by up to 25 feet subject to design review and a use permit.)

    “Required height limits are identified within the property development regulations of each zoning district and some overlay districts.”
  • Building in a floodplainLimited

    Development in Hercules areas mapped in the F Special Flood Hazard Area Overlay District.

    • The zoning code contains a dedicated F Special Flood Hazard Area Overlay District; detailed development standards were not opened.
    “All new and expanded development shall be subject to the plan review and permit conditions of the land use zoning district designated for the property along with applications and permits required within Flood Damage Prevention Ordinance.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Hercules or Contra Costa County directly.

  • Building permit — Building work inside Hercules city limits.
  • Owner-builder exemption — Owner-builder work inside Hercules city limits.
  • Inspections — Building work inside Hercules city limits.
  • Certificate of occupancy — Occupancy of buildings inside Hercules city limits.
  • Minimum dwelling size — Dwellings inside Hercules city limits.
11 more unanswered
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Well permit
  • Agricultural exemption
  • Driveway access
  • Short-term rentals
  • Permit fees

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 Hercules publishes no rule on the point, not that none exists. Contra Costa County’s page lists the county offices to call.

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