A conventional septic permit in Grayson County costs $310 for systems up to 1,000 gallons per day (GPD), and $330 for anything requiring a maintenance contract, which on most lots here means anything at all. The county quotes a five-to-seven-day process, the fastest turnaround we have verified in Texas. The catch comes earlier: on any parcel under 2.5 acres the county’s order requires aerobic treatment, so the cheap conventional tier is off the table for most buyers.
Grayson County Development Services runs on-site sewage facility (OSSF) permitting for the entire county through its OSSF Division, on the ground floor of the county building in Sherman.
Grayson County OSSF Division 100 W. Houston St., Suite G-3, Sherman, TX 75090 Phone: (903) 813-4253 or (903) 813-4247 Office hours: weekdays 8 a.m.–12 p.m. and 1–5 p.m. TCEQ authorized agent number: 620082
One point of confusion: the county’s fee schedule carries a Development Services address on the 3rd floor with a different main line, (903) 813-5275. That is the parent department. Septic applications go to the OSSF Division at Suite G-3, same building, different desk, so use the Suite G-3 numbers.
$310 for a conventional system up to 1,000 GPD, rising by $310 for each additional 1,000 GPD, with aerobic systems adding a flat $20.
From the county’s fee schedule, revision dated April 14, 2026:
| Application type | Fee |
|---|---|
| Conventional system permit, 0–1,000 GPD | $310 |
| Conventional system permit, 1,001–2,000 GPD | $620 |
| Conventional system permit, 2,001–3,000 GPD | $930 |
| Conventional system permit, 3,001–4,000 GPD | $1,240 |
| Conventional system permit, 4,001–5,000 GPD | $1,550 |
| Aerobic system permit | Add $20 to the conventional fee |
| Repair permit | $100 |
| Paper application processing | Add $50 |
| Reinspection | $100 |
| Maintenance contract renewal | $20 |
| Contract renewal late fee | Add $125 |
| Recreational vehicle design review | $500 + $50 per space over 10 |
Three things stand out. First, the residential fee is perfectly linear at $310 per 1,000 GPD with no tier breaks, so a large household pays more here than the flat bands most Texas counties use would suggest.
Second, the aerobic surcharge is $20, the lowest we have found in Texas by a wide margin; Williamson County charges $200 more. Grayson mandates aerobic far more aggressively than most counties, then barely charges for it: the cost lands on the equipment and the maintenance contract, not the permit.
Third, filing on paper costs an extra $50. The county publishes a MyPermitNow portal guide and prices paper as the exception.
The permit fee goes to Grayson County, but the Affidavit to the Public goes to the County Clerk on a second check. Aerobic owners must record that affidavit, billed at $15 for the first page and $4 for each additional page, payable to the Grayson County Clerk. Two payees, two checks; showing up with one is the most common stumble here.
Your maintenance contract renewal registers with the county for $20, but missing it adds a $125 late fee, more than six times the renewal. Calendar the date the day your contract starts. What a compliant contract must contain is covered in our aerobic maintenance contract guide.
Address and property ID first, then a site evaluation, then a filing the county turns around in five to seven days, then build, inspect, and wait for the certificate of approval by mail.
Get a current 911 address and property ID number. The county will not accept an application without both. Your property ID is on your tax statement.
Hire a licensed site evaluator or professional engineer to run the evaluation and determine what system the land supports. Verify any credential in TCEQ’s public licensing registry first.
Get the system designed. If the evaluation rules out a conventional system, likely given the 2.5-acre threshold, a non-standard or proprietary design requires a registered professional engineer or registered sanitarian.
Line up the two-year maintenance contract. For a proprietary system, purchase and installation include a two-year contract, and a copy goes to both the owner and the county at the time the application is filed. After that, buy a replacement 30 days before the current one expires, for the life of the system, copying the county every time.
Record the Affidavit to the Public with the County Clerk, stating the property supports an aerobic system and that you accept the obligations.
File the complete application with the fee. The county says permitting can take five to seven days once everything is in.
Do not break ground until the Authorization to Construct is in hand. The county states this in capitals on its own requirements sheet, which tells you how often it is ignored.
Book the final inspection at least one working day ahead of when you need it.
Watch for the certificate of approval in the mail. It issues only after the county holds every required document; a missing contract or affidavit delays it indefinitely.
Grayson County Development Services publishes the full set; pull current copies from the county, not a contractor’s folder.
$310 for a conventional system up to 1,000 gallons per day, or $330 for any system requiring a maintenance contract, plus $50 if you file on paper. Aerobic owners also pay the County Clerk $15 for the affidavit’s first page and $4 per additional page.
The county states the permitting process can take five to seven days once a complete application is submitted. That is unusually quick for Texas, but the clock starts only when the site evaluation, design, contract, affidavit, address, and property ID are in hand.
On any parcel under 2.5 acres, yes. The county’s OSSF order requires aerobic treatment below that threshold. The permit surcharge is only $20, but the equipment, the mandatory maintenance contract, and the reporting are where the real cost sits.
Only after passing a county-approved homeowner course and signing a self-maintenance agreement, and the privilege can be revoked for missed reports. The county publishes both the training-provider letter and the agreement form.
Yes. Tract size buys you nothing here. The county order covers every residential and commercial system, so the large-acreage exemption available elsewhere in Texas does not exist in Grayson.
Every fee and rule here was read in a Grayson County or TCEQ document, each named below with the date we read it.
Fees come from the county’s own spreadsheet schedule rather than a summary, which matters here: several sites still quote Grayson’s superseded figures.
Ground conditions, the Lake Texoma factor, and licensed providers: the Grayson County septic hub. Comparing what counties charge? See Texas septic permit fees by county and what routine pumping costs.
Tell us once — we send it to up to 3 verified pros. Free, no spam, delete your request anytime.
Secure form. Sent over an encrypted connection to up to 3 verified pros. Never sold to data brokers, and you can have your request deleted anytime.