Zoning, building permits and septic rules in Suisun City, California

Suisun City’s own rules

• Building code adoptedAdopted

  Building construction inside Suisun City limits

  • Subject to local amendments in chapter 15.04
  • Also adopts 2025 CRC, plumbing, electrical, mechanical, fire, energy, green building codes

  California Building Code edition: 2025

  “The 2025 Edition of the California Building Code (CBC) (Part 2 of Title 24 of the California Code of Regulations) is adopted by reference as the building code of the city.”

• Local zoningPresent

  Land inside Suisun City limits

  • Title 18 Zoning of the city code with RL, RM, RH1, RH2, RMU residential zones

  “Table 18.08.02 identifies the residential and nonresidential land uses allowed in residential zoning districts in the city.”

• Zoning districtsPublished

  Residential zoning districts inside Suisun City limits

  • Residential zones: RL, RM, RH1, RH2, RMU
  • Nonresidential districts not reviewed

  RL density: 4-10 du/ac (gross)

  “Table 18.08.01, "Densities and Intensities in Residential Zones" shows the minimum and maximum build-out possible in each residential zone.”

• Living in an RVLimited

  Recreational vehicles on sites in FEMA flood zones inside Suisun City limits only

  • Applies to zones A1-30, AH, AE, V1-30 and VE
  • RV must meet one of: under 180 consecutive days, fully licensed and highway-ready, or meet permit and elevation/anchoring requirements
  • General RV occupancy rules for non-flood areas not found in provided sections

  max stay unless highway-ready: < 180 days (or be ready for highway use or meet manufactured-home elevation standards)

  “be on the site for fewer than 180 consecutive days;”

• Camping on your landLimited

  Camping on public and private property inside Suisun City limits

  • Overnight camping on residential private property is exempt only with consent of the person in possession and no public nuisance
  • Also exempt in city-approved campgrounds and under special event permits
  • Overnight camping in marina land areas is prohibited (21.06.070)

  “Overnight camping on residential private property with consent of the person in possession or control of the private property, and where such use does not create or permit a public nuisance;”

• Manufactured homesLimited

  Manufactured and mobile homes installed on lots or in subdivisions inside Suisun City limits

  • Residential use only
  • Minimum width 20 feet
  • Roof pitch at least 3:12 and conventional exterior covering
  • No unit built more than ten years before application in any residential district
  • Single mobile homes are permitted in RL, RM, RH1, RH2, RMU; mobile home parks need a CUP

  minimum width: >= 20 feet · maximum unit age: <= 10 years

  “Be attached to a permanent foundation system in compliance with all applicable building regulations;”

• Accessory dwellingsAllowed (with conditions)

  ADUs and JADUs in residential and mixed-use zones inside Suisun City limits

  • Ministerial approval within 60 days of a complete application
  • Rental term must exceed 30 days
  • Non-state-exempt ADUs only in RL and RM: one ADU and one JADU; detached up to 850 sq ft (1 bedroom or less) or 1,000 sq ft; JADU up to 500 sq ft
  • Side and rear setback at least 4 feet; one parking space per unit or bedroom, whichever is less, with exceptions

  state-exempt detached ADU max size: <= 800 sq ft

  “detached single-family adu: one detached, new construction adu on a lot with an existing or proposed single-family dwelling.”

• Driveway accessRequired

  Front yard driveways on residential properties inside Suisun City limits

  • Public works encroachment permit (if applicable) and planning design review required
  • Paved walkways and hardscape not to exceed 60 percent of front yard area
  • An ADA curb ramp may not be used as a driveway

  max front yard hardscape: <= 60 percent

  “no front yard driveway will be permitted without the approval and issuance of an encroachment permit from the public works director of suisun city (if applicable) and design review and approval from the planning division.”

• Building in a floodplainRequired

  Manufactured homes placed or substantially improved in flood zones inside Suisun City limits

  • Zones A1-30, AH, AE: elevated on permanent foundation with lowest floor at or above base flood elevation
  • Zones V1-30, V, VE: meet section 15.08.475
  • Existing park placements are subject to elevation or pier-height alternatives certified by an engineer or surveyor

  “be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Suisun City or Solano County directly.

• Building permit — Building permits inside Suisun City limits
• Owner-builder exemption — Owner-builder permits inside Suisun City limits
• Inspections — Inspections inside Suisun City limits
• Certificate of occupancy — Certificates of occupancy inside Suisun City limits
• Minimum dwelling size — Single-family dwellings inside Suisun City limits

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.