Greywater in Tennessee: What Homeowners Need to Know
Tennessee's greywater regulations fall under the state's Subsurface Sewage Disposal Act (T.C.A. §68-221-401), which governs onsite wastewater systems. Greywater is treated as a form of household wastewater requiring county health department review. Tennessee has 95 counties, each with its own health department — processes and experience levels vary.
Tennessee's climate (47–56 inches of annual rainfall, hot humid summers) means greywater provides less irrigation value than in the arid West, but June–September can be dry enough that supplemental watering is valuable for trees and established shrubs. The state's strong rural character means many properties are on septic — the septic-specific guide is relevant for many Tennessee homeowners.
Permit Requirements & Key Rules
| Category | Requirement |
|---|---|
| Governing law | T.C.A. §68-221-401 et seq. (Subsurface Sewage Disposal Act) |
| Permit authority | County health departments |
| Nashville / Davidson County | Metropolitan Health Department, Environmental Health Division |
| Memphis / Shelby County | Shelby County Health Department |
| Knoxville / Knox County | Knox County Health Department |
| Fee range | $75–$150 typical |
| Inspection | Required post-installation in most counties |
Nashville Metro
Davidson County (Nashville) homeowners work through the Metropolitan Nashville-Davidson County Health Department's Environmental Health Division. Nashville has seen rapid growth and increased water conservation awareness. Contact Environmental Health at (615) 340-5600 or visit the Metro Nashville Environmental Health website for current application procedures. Middle Tennessee soils are predominantly clay — expect larger basin requirements and do a percolation test first.
Memphis & Knoxville Areas
Shelby County (Memphis) and Knox County (Knoxville) both have established health departments that handle greywater inquiries. Memphis is in the Mississippi River alluvial plain — soils can be very heavy clay with poor drainage. Do a thorough percolation test before planning basins. East Tennessee (Knoxville area) has more varied soils and some sandy loam in river valleys. Contact your county health department's environmental health division directly.
What Tennessee Allows (and Doesn't)
Allowed: Subsurface or mulch-covered irrigation of ornamental plants, lawns, shrubs, trees, and fruit trees (water applied away from fruit). Laundry-to-landscape systems using washing machine water only. Systems with sewer or septic overflow connection.
Not allowed in any state: Spray irrigation, edible crop irrigation, greywater crossing property lines, surface ponding, storage over 24 hours without treatment (for shower systems).
How to Install a Legal L2L System in Tennessee
The laundry-to-landscape (L2L) system is the simplest residential greywater system in Tennessee and requires the least regulatory overhead. See the complete L2L installation guide for step-by-step instructions covering materials, diverter valve installation, mulch basin construction, and testing. Use the sizing calculator to get exact basin dimensions for your household and soil type.
Frequently Asked Questions — Tennessee Greywater
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Tennessee averages 48–56 inches of rain, but it's distributed unevenly through the year. The June–August period can see dry spells where supplemental irrigation is genuinely needed for trees and established landscape plants. The primary value of greywater in Tennessee isn't daily water savings (like in Arizona) — it's drought resilience when restrictions hit, and extending established plants through dry stretches. The payback period is longer than in the West, but the system cost is also low enough that it pencils out over 3–5 years in most cases.
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Call your county health department's environmental health division and explain you want to install a laundry-to-landscape system — a simple valve and tubing directing washing machine water to mulch basins in the yard. Ask what their process and fees are. In most Tennessee counties, you'll get a straightforward application process with a modest fee. Getting the county's informal blessing, even if the formal permit process is light, is the right first step.