Quick answer

Yes. Rainwater collection is fully legal in Tennessee, with no state limits on how much you can collect from your roof.

What Tennessee law says

Tennessee places no state-level restrictions on residential rainwater harvesting. You can install as many barrels or cisterns as your property supports, and no permit or registration is required. Legal for non-potable domestic use. SB 2417/HB 1850 supports rainwater harvesting as green infrastructure. As always, check for HOA covenants or local ordinances before installing a larger system.

How much water a Tennessee roof can collect

Tennessee averages about 54 inches of rain per year. On a typical 1,200 square foot roof at 85% collection efficiency, that works out to roughly 34,300 gallons a year currently running into your storm drain. A single one-inch storm delivers about 635 gallons, enough to fill 13 standard 50-gallon barrels.

54"

Average annual rainfall in Tennessee.

34,300

Gallons per year from a typical 1,200 sq ft roof.

$412

Approximate annual value at municipal water rates.

Your roof and rainfall will differ; run your exact numbers in the rainwater calculator.

The right setup for Tennessee’s climate

At roughly 54 inches of rain a year, Tennessee is a wet-climate state; your barrel will refill constantly. Prioritize a sealed, mosquito-proof design and plan the overflow path. A 50-gallon barrel with a diverter that returns excess water to the downspout is the right call.

Our pick for Tennessee

Rain Wizard 50 + Diverter Kit, reviewed against our independent testing criteria. See all six models side by side.

Common questions

Is it illegal to collect rainwater in Tennessee?
Yes. Rainwater collection is fully legal in Tennessee, with no state limits on how much you can collect from your roof. This is educational information, not legal advice.
Do I need a permit for a rain barrel in Tennessee?
No. Tennessee requires no permit or registration for residential rainwater collection at any scale.
Does Tennessee offer incentives for rainwater harvesting?
Legal for non-potable domestic use. SB 2417/HB 1850 supports rainwater harvesting as green infrastructure.

Sources

  1. Rainplan, 50-State Rainwater Collection Guide (2026)
  2. State statutes and water agency guidance for Tennessee
  3. NOAA National Centers for Environmental Information, annual precipitation normals
  4. US EPA WaterSense, Outdoor Water Use fact sheet

Educational content, not legal advice. Laws change; confirm current rules with your state water agency.