Septic system requirements in California
What landplan.io applies when it designs a septic system in California: the system types allowed, tank sizes, setbacks and soil loading rates, with what septic products cost there.
Updated
Design a septic system for an address in California
Reviewed landplan.io designs by California's own rules, which our staff reviewed against the state's regulations. Last published 6 October 2026.
Septic systems allowed in California
The system types landplan.io permits in California:
- Drip Distribution System
- Leach Line System
- Horizontal Seepage Pit System
- Vertical Seepage Pit System
- Mounded Leaching System
- Infiltrator Advanced Treatment Leachfield (ATL)
- Infiltrator Advanced Enviro-Septic® (AES)
Septic tank size in California
The daily design flow of a home: 150 gal/day per bedroom, at least 150 gal/day. The septic tank is sized from that flow:
| Daily design flow | Minimum tank |
|---|---|
| up to 240 gal/day | 1,000 gallons |
| 240 to 360 gal/day | 1,500 gallons |
| 360 to 600 gal/day | 2,000 gallons |
| 600 to 720 gal/day | 2,500 gallons |
| 720 to 840 gal/day | 2,750 gallons |
| 840 to 920 gal/day | 3,000 gallons |
| 920 to 1,040 gal/day | 3,250 gallons |
Septic setbacks in California
| From | To | Distance |
|---|---|---|
| Polygon | Existing Septic Component to be Abandoned | 5 ft |
These are the values the landplan.io design engine applies in California. Confirm a design with the California health department or your county's before you build.
Septic system costs in California
| Product | Median | Typical range | Listings |
|---|---|---|---|
| Septic Tank | $1,720 | $1,577 – $1,803 | 15 |
The California price index: every product type, month by month.
Parcel data in California
landplan.io has parcel boundaries for 57 of California's 58 counties: the counties where 100% of the state's people live. Type an address there and the design starts from the parcel.
Septic companies, designers and jobs in California
- Septic companies and distributors in California (87)
- Septic designers in California
- Septic design jobs in California
Where the rules come from
The regulations and documents landplan.io's California rules are read from:
- Water Quality Control Policy for Siting, Design, Operation, and Maintenance of Onsite Wastewater Treatment Systems (OWTS Policy) (State Water Board Resolution No. 2012-0032 (OWTS Policy), codified references at 23 CCR §2, Div. 3, Ch. 15.5)
- 2025 California Plumbing Code, Appendix H - Private Sewage Disposal Systems (with Sections 713.0-721.0 of Chapter 7) (Cal. Code Regs. Title 24, Part 5 (2025 California Plumbing Code), Appendix H, Sections H 101.0-H 1201.0; Tables H 101...)
Septic rules by county in California
1 county has rules of their own in landplan.io (marked ★); the others follow California's.
- Alameda County
- Alpine County
- Amador County
- Butte County
- Calaveras County
- Colusa County
- Contra Costa County
- Del Norte County
- El Dorado County
- Fresno County
- Glenn County
- Humboldt County
- Imperial County
- Inyo County
- Kern County
- Kings County
- Lake County
- Lassen County
- Los Angeles County
- Madera County
- Marin County
- Mariposa County
- Mendocino County
- Merced County
- Modoc County
- Mono County
- Monterey County
- Napa County
- Nevada County
- Orange County
- Placer County
- Plumas County
- Riverside County
- Sacramento County
- San Benito County
- San Bernardino County
- San Diego County ★
- San Joaquin County
- San Luis Obispo County
- San Mateo County
- San Srancisco County
- Santa Barbara County
- Santa Clara County
- Santa Cruz County
- Shasta County
- Sierra County
- Siskiyou County
- Solano County
- Sonoma County
- Stanislaus County
- Sutter County
- Tehama County
- Trinity County
- Tulare County
- Tuolumne County
- Ventura County
- Yolo County
- Yuba County
Questions
What septic systems are allowed in California?
landplan.io permits these system types in California: Drip Distribution System, Leach Line System, Horizontal Seepage Pit System, Vertical Seepage Pit System, Mounded Leaching System, Infiltrator Advanced Treatment Leachfield (ATL) and Infiltrator Advanced Enviro-Septic® (AES).
What size septic tank do I need in California?
landplan.io sizes the septic tank in California from the daily design flow: up to 240 gal/day: 1,000 gallons; 240 to 360 gal/day: 1,500 gallons; 360 to 600 gal/day: 2,000 gallons; larger flows need larger tanks. A home's design flow is 150 gal/day per bedroom, at least 150 gal/day.
Does landplan.io have parcel data in California?
Yes, for 57 of California's 58 counties.