Perc Tests and Soil Evaluations in Tennessee

Called here: Percolation Test or Soil Evaluation/Soil Map (Approved Soil Consultant)

First identify whether TDEC or one of Tennessee's nine contract counties handles the property, because local requirements can differ. In the state-direct path, submit the application, fee, site details, and sketch, adding a soil map or engineering design only when required. Mark property lines and corners, stake the building and other planned structures, and clear the evaluation area. A TDEC Environmental Scientist evaluates the site and may request a detailed plan, private soil map, or other information. If a percolation test is used, give TDEC at least three days' notice. TDEC says state-direct review generally takes about 10 days and a permit will be granted or denied within 45 days after all necessary information arrives. These are review figures, not a complete project schedule, and contract-county timing may differ.

Tennessee recognizes both literal percolation tests and soil evaluations or soil maps, and a test rate does not approve a site by itself. An individual lot outside a subdivision may first be evaluated by a TDEC Environmental Scientist without a plat-based private soil evaluation. Hire an Approved Soil Consultant when the permitting office or required work calls for a consultant-prepared map; contract counties can set their own documentation rules. Tennessee's statute and rule do not appear to provide a general acreage-based permit exemption for an individual residential lot. The commissioner may waive some provisions for subdivisions with fewer than five lots, but that is a discretionary partial waiver for small subdivisions, not a blanket large-lot exemption. Confirm required documents and any waiver with TDEC or the county before ordering work.

No private-evaluator price appeared on the five accessible Tennessee operator sites checked, and a sixth site was blocked, so there is no verified operator benchmark. Get written quotes from two or three Approved Soil Consultants and keep that charge separate from government fees. For TDEC-direct work, a new conventional permit up to 1,000 gallons per day is $400 and its construction inspection is $100; a new alternative permit is $500 and its inspection is $200. Repair permits have no fee, but repair inspection is $100. The sources do not establish exactly when each inspection charge is collected, so confirm the payment schedule. Contract-county examples are $175 in Shelby, $40 for lot evaluation plus $200 for installation and layout in Knox, and $400 per dwelling in Hamilton. They are examples, not a uniform schedule.

A Tennessee percolation test has an exact procedure: keep at least 12 inches of water over gravel in the hole for at least four hours, preferably overnight; begin measurements 24 to 30 hours after the initial filling; then read the rate about every 30 minutes for four hours. This procedure is not the total time for scheduling, reporting, permitting, construction, or inspection. No sourced statewide end-to-end duration or best season was found. The construction rule separately says trenches may not be excavated when soil is wet enough to smear or compact easily. It does not extend that restriction to site visits or soil mapping, so discuss possible weather-related evaluation delays with the evaluator rather than assuming them from the excavation rule.

Tennessee does not use one credential called a licensed percolation tester. A Tennessee-licensed engineer or surveyor, professional geologist, Approved Soil Consultant, registered professional environmentalist, or certain experienced environmental health professionals may conduct a percolation test under the rule. Only an Approved Soil Consultant prepares the general, high-intensity, and extra-high-intensity soil maps used in this process. Base GEN & HIGH approval requires qualifying education and experience, written and field scores of at least 80 percent, tentative approval, and successful review of the first five high-intensity maps. The optional ALL MAPS track adds extra-high-intensity work after further experience, mapping, training, and review. TDEC's roster has no published ID numbers, so verify current approval and map designation against the roster or with regional soils staff.

Tennessee Department of Environment and Conservation (TDEC), Land-Based Systems Unit · Verify a license