Septic Permits for a New Home in Middle Tennessee

October 19, 2026 · by Michael Blair, Nashville's Contractor

A lot of the calls we get start the same way: someone has the land, maybe a few acres outside Franklin or Lebanon, and needs a builder. On most rural parcels in Middle Tennessee there is no sewer main at the road, so the house cannot be drawn, priced or permitted until the ground has been approved for a septic system. That approval comes from the state or the county, not from us, and the soil decides what kind of system the house gets and where it can go. Here is how the permit works, so the first visit to the land does not set the job back.

Who issues a septic permit for a new house in Tennessee?

The Tennessee Department of Environment and Conservation’s Division of Water Resources issues it, and its septic system FAQs say a permit is required for the construction, modification or repair of a septic system, residential or otherwise. A new house on land without sewer is construction, so the permit comes before the system is built.

In a handful of counties the county handles it under contract with the state. TDEC’s page on third-party permits and final inspections lists those contract counties, and Williamson and Davidson are the two on that list in our part of the state. A lot near Franklin or Brentwood goes to Williamson County; anywhere the list does not name, the application goes to TDEC.

Inside Davidson County, many lots can tie into a public sewer instead. Metro Water Services’ water and sewer permits page says taps are paid for and scheduled through Metro’s ePermits system, and whether a line reaches a given parcel is a question for MWS. Sewer or septic is the first thing we find out about any lot on our custom homes jobs.

Why the house has to be placed before the soil is tested

The staking rules mean the house is located on the land before anyone looks at the soil. The evaluator is judging whether the ground around a specific pad can take a system, so moving the pad after the visit can put the house on the wrong side of the soil that was approved. We walk the lot, settle the house position with the owner and stake it, and only then ask for the evaluation.

The last rule matters most on a building lot. Clearing and grading are usually the first work on a new house, and our site work and hardscapes crews would normally be cutting a driveway and a pad early on. On a septic lot, that work waits until the evaluation is done, because cut or filled ground is not the soil the state needs to see. How each lot drains and what sits under it varies across Middle Tennessee, so the order of the dirt work is something we decide lot by lot.

The evaluator may also ask for a site plan or a soils map from a private soil consultant. TDEC keeps a list of approved soil consultants on its soil consultants page, and since July 1, 2025 the department itself approves them.

Sources

• TDEC Division of Water Resources: Subsurface Sewage Disposal System FAQs — Permit requirement, the site evaluation, lot preparation, the 45-day processing time, fees, denial notices and the final inspection.
• TDEC Division of Water Resources: Third-Party Permits and Final Inspections — Engineer and soil scientist submittals since October 1, 2024, the contract counties, and the 10-business-day review.
• TDEC Division of Water Resources: Soil Consultants — The list of approved soil consultants and TDEC approval since July 1, 2025.
• Metro Water Services: Water and Sewer Permits — Sewer taps in Davidson County paid for and scheduled through ePermits.