Updated 18 April 2026
Every septic system installation or significant repair requires county health department approval. Permit fees run $200-$500 for a standard install; engineered designs for alternative systems add $500-$2,500. Most of the permit timeline is waiting - the actual review rarely takes more than 1-2 days, but permit queues in busy counties can add 2-8 weeks. Plan for 2-5 months from the first perc test to an operational system.
These are federal baseline minimums. Many states and counties set stricter requirements. Always verify with your county health department.
| From / To | Tank | Drain Field |
|---|---|---|
| Private well (on-lot) | 50 ft | 100 ft |
| Foundation / structure | 10 ft | 10 ft |
| Property line | 10 ft | 10 ft |
| Surface water (stream, lake, pond) | 50 ft | 100 ft |
| Public water supply well | 100 ft | 200 ft |
| Wetlands or vernal pools | 50 ft | 100 ft |
| Irrigation ditch or drainage channel | 25 ft | 50 ft |
| Underground water or sewer lines | 10 ft | 25 ft |
An engineered design (stamped by a PE) is required in most states for any of the following:
The strictest and most comprehensive state program. Mandatory inspection on property sale. Systems failing Title 5 must be upgraded within 2 years. 310 CMR 15.000. Administered by local Boards of Health.
Prescriptive and performance-based options. Western Washington: high engineering requirement rate. Eastern Washington: simpler permits. Counties can add requirements beyond state rules.
TCEQ has statewide rules but significant variation by county. ATU service contracts mandatory. Some rural counties allow owner-installation with permit and inspection.
County-based Local Area Management Programs. Varies more by county than any other state. Bay Area counties are among the most complex. Contact county Environmental Health.
State minimum code; county health departments often adopt stricter rules. Suffolk County: extensive additional rules for nitrogen-sensitive areas. NYC suburban counties: complex permitting.
OSTDS program moved from FDOH to FDEP in 2021 (rule renumbered from 64E-6 to 62-6). Statewide minimum 900-gallon tank. ATU service contracts mandatory. Southeast Florida: ATU-only zones for many parcels. FDEP has separate rules for systems near aquifer recharge areas.
Reader Questions
Send the question over. A person reads each one, and the answer names the source it leans on, whether that is a state code, a county fee schedule or a published installer range. If your question turns out to be one plenty of people on rural lots are asking, we will ask you first, then put an anonymised version up here.
What this is not. A cost reference, not a design, engineering or permitting decision. The percolation result, the system sizing and the permit itself sit with your county health department and a licensed installer who has walked the lot.
Updated 2026-04-27