Budget $325 for a standard residential septic permit in Gillespie County, $425 if the system needs a maintenance contract (which every aerobic unit does), and $200 for repairs or alterations to an existing system — figures from the county’s fee schedule effective October 14, 2025. Two things changed here recently: the county adopted an updated OSSF order the same day those fees took effect, and since August 1, 2025, you must clear a floodplain determination with the County Engineer before the Sanitation office will consider your septic application complete.
$325 covers most homes; maintenance-contract systems pay $425; and large or commercial systems at 500+ gallons per day run $550–$750. The county’s current schedule in full:
| Application type | Fee (eff. 10/14/2025) |
|---|---|
| New or upgrade, under 500 GPD | $325 |
| New or upgrade requiring maintenance contract, under 500 GPD | $425 |
| New or upgrade, 500 GPD or greater | $550 |
| New or upgrade w/ maintenance contract, 500 GPD or greater | $750 |
| Repair or alteration (existing system) | $200 |
| Reinspection | $150 |
That $150 reinspection fee deserves respect: if construction isn’t ready when the inspector arrives, the do-over costs nearly half the original permit fee. Gillespie also charges more than neighboring Kerr ($250/$300) — one more reason to price the whole project, not just the contractor’s bid.
Since August 1, 2025, every septic application needs a signed Development Permit Determination — a floodplain review — from the Gillespie County Engineer’s office before the OSSF office will treat your file as complete. Submit the Development Permit Determination and Site Plan with Narrative forms to the Engineering Department (830-307-6196) first; the signed copy then travels with your septic paperwork. Applications that skip this step stall on arrival. It replaces the county’s old “Development Permit” and generally applies to new construction — the Engineer’s office decides whether your parcel needs further review.
Gillespie County’s Sanitation (On-Site Sewage Facilities) Department is the TCEQ-designated permitting authority for the county — applications are filed on county forms with this office.
Gillespie County Sanitation (OSSF) Department 101 West Main St., Room B-101, Fredericksburg, TX 78624 Mailing: 101 West Main St., Mail Unit 9, Room B-101, Fredericksburg, TX 78624 Phone: (830) 997-8191 · Fax: (830) 997-9867 Email: OSSF@gillespiecounty.gov Hours: Monday–Friday, 8 a.m.–noon and 1–5 p.m.
There’s no online portal; the application is a fillable county PDF that you file with the office along with your fee and supporting materials. A filed application stays valid for one year from purchase, so permitting ahead of a build season costs you nothing.
The form asks for more than a name and address: GCAD property ID, total acreage, water source (private well or supplier name), bedroom and bathroom counts, living-area square footage, water-saving fixtures, and whether a water softener is plumbed separately from the septic system — each answer feeds the sizing math. Well permitting is separate and handled through the Hill Country Underground Water Conservation District (830-997-4472).
A complete Gillespie County file contains the signed floodplain determination, the site evaluation, planning materials from your installer or designer, the application form, and — for aerobic systems — two extra documents: an Affidavit to the Public and a two-year maintenance contract.
Gillespie County publishes a current list of installers working in the county and a separate list of area aerobic maintenance providers — both updated May 2026 — and every name on your contract should also clear TCEQ’s license search. The Sanitation Department page hosts both PDFs alongside the application. Cross-checking takes two minutes at TCEQ’s licensing lookup (www2.tceq.texas.gov/lic_dpa/index.cfm); our Gillespie County hub adds the license-verified directory view. Installation requires an Installer I at minimum and Installer II for aerobic units; site evaluation and aerobic maintenance carry their own license classes.
Download current versions from the Sanitation Department’s page at gillespiecounty.gov rather than reusing a contractor’s old copies — the application changed in July 2025 and the fees in October 2025:
$325 for a typical home, $425 when a maintenance contract is required (aerobic), $200 for repairs, and $550–$750 for systems at or above 500 gallons per day. Add $150 if an inspection has to be repeated.
Don’t assume it — call the Sanitation office at (830) 997-8191 before building on that basis. The state’s 10-acre exemption is already narrow (one single-family dwelling, all components 100+ feet off property lines, effluent kept on-site); local orders may impose stricter requirements, and Gillespie adopted an updated OSSF order in October 2025. Get the county’s answer on your specific tract in writing.
The county inspects after construction and before the system is covered — burying work without that inspection is the costliest mistake available, because correcting it means re-excavation. Schedule realistically with your installer; a missed appointment incurs a $150 reinspection fee.
Ask the Sanitation office for the system’s permit file and schematic, confirm any aerobic unit has an active maintenance contract, and verify the servicing provider appears on the county’s aerobic maintenance list. A recorded Affidavit to the Public will surface in your title search for maintained systems; no permit file at all is a conversation to have before closing, not after.
Ground conditions, provider listings, and the wider picture: Gillespie County septic hub.
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