Ohio septic rules
Ohio septic tank size & cost
Ohio requires the biggest tanks in our first ten states. A typical new 3-bedroom system in Ohio runs about $8,800–$13,500 installed by our line-by-line estimate. Below: the state's actual size rule, the full table, and where every number comes from.
Rule: Ohio Administrative Code 3701-29-12(C)(1) · Administered by Ohio Department of Health · Read the official text · Checked 2026-11-08
Ohio's rule, in plain words
Ohio's table (OAC 3701-29-12) starts where other states finish: 1,000 gallons covers only 1–2 bedrooms, a 3-bedroom home needs 1,500, and 4–5 bedrooms need 2,000. Anyone who moves to Ohio from a neighboring-rule state and buys 'the usual 1,000-gallon tank for a 3-bedroom' is 500 gallons short of the legal minimum.
Ohio also mandates the tank's construction: from three bedrooms up, the tank must have two compartments. Six or more bedrooms start at 2,500 gallons and add 250 per bedroom.
The Ohio size table
| Bedrooms | Minimum tank (gal) | With garbage disposal |
|---|---|---|
| 1 | 1,000 | 1,000 |
| 2 | 1,000 | 1,000 |
| 3 | 1,500 | 1,500 |
| 4 | 2,000 | 2,000 |
| 5 | 2,000 | 2,000 |
| 6 | 2,500 | 2,500 |
Garbage disposal: Ohio's capacity table states no separate garbage-disposal allowance.
Ohio requires some of the largest tanks in the country — a 3-bedroom home needs 1,500 gal here, versus 1,000 gal in neighboring-rule states.
Check your Ohio home
State minimum — your county can require more. Estimate this system's cost →
What a Ohio system costs
Our estimator prices a conventional 3-bedroom system in Ohio (typical-cost area, 1,500-gal tank) at $8,800–$13,500 installed, assembled from a soil test, the permit, the tank at published prices, drainfield material, fittings and labor. Build your own estimate →
How Ohio compares (3-bedroom minimum)
Full ten-state chart: septic tank size chart.
Other states we've checked
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