Zoning, building permits and septic rules in San Dimas, California

San Dimas’s own rules

• Building code adoptedAdopted (with conditions)

  Construction, alteration, use and occupancy of buildings and structures inside San Dimas city limits

  • Adopts California Building Code, 2025 edition, Volumes 1 and 2, with appendix chapters C, F, I and J, which the city states are based on the 2024 International Building Code.
  • Chapter 15.04 contains city amendments to CBC Chapter 1 (Section 15.04.020) and to Appendix J grading (cubic-yard threshold and erosion control).
  • Adoption text is in eCode360 Chapter 15.04 with prior ordinance history Ords. 423, 436, 299 and 275; the effective date of the 2025 adoption was not stated on the page opened.

  “except as provided in this chapter, those certain building codes known and designated as the california building code, 2025 edition, volumes 1 and 2”

• Local zoningPresent (with conditions)

  Land inside San Dimas city limits; the city administers its own zoning code (Title 18, Zoning)

  • Use, district and dimensional rules are in Title 18 and were not opened in this run; see the unknown dimensional and district claims.

  “volume ii zoning code title 18 zoning (§ 18.04.010 – § 18.544.810)”

• Living in an RVProhibited

  Using a house car (motor home or RV) as a place of habitation or residence anywhere inside San Dimas city limits

  • Exception: nothing in the section prohibits a house trailer or mobile home used as an abode in an approved mobile home park, if it complies with all other conditions and requirements of the code.
  • Text is the city's amendment to CBC section 101.2 (scope); it does not address RV parking or storage, which is governed by Title 18 (not opened).

  “it is hereby declared unlawful to use any streetcars, boxcars, house cars, motor bus bodies, or similar means of conveyance or structures of similar nature of construction, for places of habitation, residence, or place of business in this city.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask San Dimas or Los Angeles County directly.

• Building permit — New construction and alterations inside San Dimas city limits
• Owner-builder exemption — Owner-builder permits in San Dimas city
• Inspections — Inspections of new construction inside San Dimas city limits
• Zoning districts — Zoning district map and list for San Dimas city
• Minimum dwelling size — Minimum dwelling size in San Dimas city residential zones

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.

Off-grid gear

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

• Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
• Power Bluetti Solar generators and home battery backup for living off the grid.
• Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
• Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.

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