The Governing Framework

Tennessee regulates onsite wastewater through the Department of Environment and Conservation (TDEC) Division of Water Resources:

• Tennessee Comprehensive Rules & Regulations 0400-48-01 — Regulations to Govern Subsurface Sewage Disposal Systems.
• 0400-48-01-.07 — Design of the Conventional Disposal Field.
• 0400-48-01-.11 — Location of Septic Tanks, Dosing Chambers and Absorption Fields (setback table).
• 0400-48-01-.20 — Septic Tank Pumping Contractor licensing.
• County health departments — issue construction permits under TDEC delegation. The Tennessee Department of Health (through county EH offices) handles the field-level permitting.

Disposal Field Design — 0400-48-01-.07

Tennessee's trench-style conventional disposal field requirements:

Permit Process

1. Contact your county environmental health office. All permits are issued at the county level under TDEC delegation.
2. Soil site evaluation. Soil scientist or environmental specialist performs a perc test or soil profile per TDEC protocol.
3. Design submittal. Plot plan, soil results, system sizing, setback documentation.
4. Permit issuance. Typical fees $200–$600 depending on county. Timeline 2–6 weeks.
5. Installation. By a TDEC-licensed installer. A separate installer license from tank pumpers (who are licensed under 0400-48-01-.20).
6. Pre-cover inspection. County inspects tank placement, pipe, trench, and dispersal before backfill.

Regional Considerations

• Cumberland Plateau (Crossville, Sparta, Jamestown): Rocky sandstone/shale layers often force extended trenches, alternative technologies, or off-site dispersal.
• Nashville Basin: Limestone karst terrain with sinkhole risk. Some counties require geotechnical review for systems near documented sinkhole zones.
• West Tennessee (Memphis, Jackson): Loess and alluvial soils over high water tables near the Mississippi. Pressure distribution or mound systems common.
• East Tennessee (Knoxville, Chattanooga): Valley-and-ridge topography. Steep-slope installations require stepped dispersal or contour trenching.
• Lake communities (Watts Bar, Douglas, Cherokee): TVA and surface-water setbacks compound with 0400-48-01-.11 requirements. Consult county EH before assuming a parcel is buildable.

Material Approvals

TDEC accepts polyethylene septic tanks meeting industry standards (IAPMO/UPC listing, ASTM D1998). Major OEMs (Norwesco, Snyder, Chem-Tainer) have approved configurations. Check at order:

• IAPMO PS 1 or NSF 46 listing.
• Ribbed polyethylene construction rated for soil-cover conditions.
• Baffle arrangement meeting 0400-48-01 design specifications.
• Riser/access port compatibility with county-specific inspection-port requirements.

Frequently Asked Questions

Do I need a state permit or a county permit?

County environmental health issues the construction permit under TDEC delegation. The state rule (0400-48-01) sets the substantive standards; the county inspects and approves. Always start with your county EH office.

What's a "functional equivalent" to Schedule 40 PVC?

SDR-35 PVC, Schedule 40 ABS, or HDPE pipe rated for the same burial depth and loading. Confirm with your county before ordering material — some counties accept only Schedule 40 PVC by default.

Can I install an alternative system like an ATU or drip dispersal?

Yes, with TDEC and county approval. Approved product lists are maintained at the state level. Alternative systems require PE-stamped designs in most counties.

What's the rule for pumping contractors?

Under 0400-48-01-.20, septic tank pumpers must hold TDEC licensing separate from installer licensing. Pumping frequency is not set statewide — most counties recommend every 3–5 years for a typical family-of-four 1,000–1,250 gallon tank.

Source Citations

• TDEC Regulations to Govern Subsurface Sewage Disposal Systems
• 0400-48-01 full rule text (PDF, TN SOS publications)
• 0400-48-01-.07 Design of the Conventional Disposal Field
• 0400-48-01-.11 Location of Septic Tanks
• TDEC Septic System Construction Permit

Agricultural Tank Regulations — Tennessee Department of Agriculture

The Tennessee Department of Agriculture (TDA) regulates pesticide storage, handling, and bulk fertilizer operations through its Division of Regulatory Services. TDA rules are codified in Title 0080 of the Tennessee Comprehensive Rules and Regulations, with the pesticide chapters running in the 0080-05 series.

• 0080-05-07 — Standards for storage and handling of anhydrous ammonia. Bulk storage is defined at 1,200 water gallons or more. Minimum shell thickness is 3/16 inch; underground containers must be buried at least 24 inches deep and coated with red lead plus two heavy coats of coal tar or asphalt.
• TDA Division of Regulatory Services — Pesticide Section — administers registration, licensing, and enforcement of pesticide use, handling, storage, and application under the Tennessee Pesticide Control Act.
• Liquid fertilizer storage — registrants must comply with TDA container and labeling rules. For agricultural operations in the Tennessee River and Cumberland River watersheds, bulk UAN and other liquid nitrogen sources are commonly stored in polyethylene vertical tanks with containment compatible with the TDEC aquifer protection framework.
• Aquifer protection — TDEC's Groundwater Protection Program (under Water Resources) overlays any agricultural bulk-storage site. Sinkhole and karst terrain in Middle Tennessee frequently triggers enhanced setback and containment requirements beyond the state ag baseline.

Bulk chemical applicators should confirm operator licensing through TDA's online portal and verify that containment meets both TDA agricultural rules and TDEC groundwater rules before commissioning any new bulk tank site. For specific fee schedules and per-county application rules, consult the TDA Division of Regulatory Services directly.

Oil & Gas Produced Water — TDEC Oil & Gas Program

Tennessee's oil and gas activity is concentrated in the Chattanooga Shale and Devonian carbonates of the Cumberland Plateau and Upper East Tennessee. Produced water, brine, and drilling waste are regulated under:

• Rule Chapter 0400-54 — TDEC Division of Water Resources, Oil and Gas Program — Production.
• Rule Chapter 0400-18-01 — Petroleum Underground Storage Tanks.
• Tennessee Board of Water Quality, Oil & Gas — rule-adopting authority.
• T.C.A. § 69-3-104 — enabling statute for the oil and gas program.

Operators handling produced water at the well site must use tanks with adequate secondary containment, meet API-family design standards, and report releases to TDEC's 24-hour line. Disposal is typically via Class II UIC wells authorized under the Safe Drinking Water Act. For specific reporting fees and permit timelines, contact the TDEC Oil and Gas Program directly.

Septic System Sizing Deep Dive

Beyond the trench-design rules in 0400-48-01-.07, Tennessee sizes tanks on a bedroom-count-plus-flow basis. Design flow is the governing variable: systems are sized for the greater of the bedroom baseline or measured peak flow for non-dwelling uses.

Setbacks under 0400-48-01-.11 include minimums to private wells, property lines, surface water, and building foundations. Specific numbers vary and have been updated; confirm the current table with your county environmental health office before finalizing a site plan. For a buildable-lot check, request a soil site evaluation before contract.

Chemical Storage Secondary Containment & Spill Reporting

Federal SPCC applicability begins at 1,320 gallons aggregate aboveground oil storage (40 CFR 112). Tennessee follows the federal floor and layers on state spill reporting:

• TDEC 24-hour release reporting: Hazardous substance releases above federal reportable quantities must be reported to TDEC at 1-888-891-8332, and federal RQ releases to the National Response Center at 1-800-424-8802.
• Rule 0400-40-05 — includes 24-hour reporting for any water-pollution noncompliance or release.
• Rule 0400-18-01-.05 — additional state release notification requirements for hazardous materials accidents.
• Rule 0400-15-01 — Hazardous Substance Remedial Action program (the Tennessee analog to CERCLA for state-designated substances).

Polyethylene chemical tank owners should map their inventory against federal RQs in 40 CFR 302.4 and build a written SPCC plan above 1,320 gallons aggregate. Secondary containment should hold at least 110% of the largest tank capacity. Consult the TDEC Division of Remediation for site-specific thresholds.

Permit Pathways at a Glance

Which application needs what permit in Tennessee:

• Residential septic tank: County environmental health construction permit under TDEC 0400-48-01 delegation.
• Bulk ag chemicals > 1,200 gal anhydrous: TDA registration under 0080-05-07.
• Bulk pesticide/fertilizer retail: TDA Division of Regulatory Services licensing.
• Oil & gas produced water storage: TDEC 0400-54 registration plus UIC authorization for disposal.
• Aboveground oil > 1,320 gal aggregate: Federal SPCC plan, no separate TN permit but state spill reporting applies.
• Petroleum UST: TDEC 0400-18-01 registration and fees; fees and timelines vary — consult the state agency directly.

More Tennessee FAQs

Do I need a state permit to install a 500-gallon above-ground diesel farm tank?

Not under SPCC if that 500 gallons is your total aboveground oil storage — you're below the 1,320-gallon federal threshold. Tennessee has no additional state registration for small farm tanks, but any release that reaches a waterway triggers TDEC 24-hour reporting.

How is aquifer protection enforced in karst country?

TDEC's Groundwater Protection Program can impose site-specific conditions on any installation in a designated sinkhole zone. In Middle Tennessee, the county EH office will often refer ambiguous sites to TDEC Water Resources before issuing a septic permit.

What happens if I release 50 gallons of 32% UAN on a concrete pad?

Contain, clean up, and document. If any of the fertilizer reaches a storm drain or creek, it's reportable to TDEC immediately. Dry sweep, apply-to-field where possible, and follow your SPCC or facility response plan.

Is there a state-funded cleanup program like Tennessee's PST fund for chemical tanks?

No. The Petroleum Underground Storage Tank Fund covers regulated petroleum USTs only. Non-petroleum chemical tanks are the owner's liability with no state reimbursement pool.

Does Tennessee have specific rules for dairy operations and milk-house wash water?

Dairy operations fall under a mix of TDEC water quality rules and TDA dairy regulations. Wash water and parlor cleanup wastewater typically cannot be sent to a standard septic system and require either a separate treatment loop or an agricultural wastewater permit. Operators with 200+ cows should plan for a TDEC CAFO framework under 0400-40-05.

Are there specific setbacks for poultry house bulk propane and water tanks?

Propane storage follows NFPA 58 and Tennessee State Fire Marshal rules. Bulk water tanks for poultry operations are unregulated by TDEC or TDA beyond general water-withdrawal reporting if the source is a permitted well. Check your county for any local zoning or floodplain restrictions on tank pads before pouring concrete.

What's the process for reporting an agricultural chemical spill to multiple agencies?

Use the TDEC emergency line (1-888-891-8332) as your primary state touchpoint. TDEC will coordinate with TDA for ag-chemical incidents and with the National Response Center for federal-RQ events. Do not delay notification to triangulate which agency — single-point reporting to TDEC satisfies state obligations and triggers the appropriate inter-agency referral.

Do I need a separate permit for stormwater runoff from my tank pad?

If your site exceeds one acre of disturbance during construction, the TDEC Construction General Permit (CGP) under 0400-40-10 applies. Once operational, industrial sites with material storage may need coverage under the TDEC Multi-Sector General Permit (MSGP). Agricultural operations are typically exempt from the industrial stormwater program but must still avoid discharges that trigger the 0400-40 water-pollution rules.

Who approves polyethylene tanks for on-farm agricultural use?

TDA doesn't maintain an approved-tanks list for ag chemicals. Buyers should verify that the polyethylene tank is chemical-compatible with the stored product (see our chemical compatibility database), meets the relevant ASTM standard, and is sized for containment requirements.