State rules
Septic tank rules by state
We read each state's septic rule from the official code and check the numbers line by line before a state appears here. Ten states are live; the other forty are added only when their rule has been verified the same way — we would rather show ten states we can defend than fifty we copied.
Texas3-bedroom minimum: 1,000 gal · New system ≈ $7.6k–$12.1k
Florida3-bedroom minimum: 1,050 gal · New system ≈ $8k–$12.4k
North Carolina3-bedroom minimum: 1,000 gal · New system ≈ $6.9k–$11.1k
Ohio3-bedroom minimum: 1,500 gal · New system ≈ $8.8k–$13.5k
New York3-bedroom minimum: 1,000 gal · New system ≈ $10.7k–$16.7k
Pennsylvania3-bedroom minimum: 900 gal · New system ≈ $7.6k–$12.1k
Virginia3-bedroom minimum: 900 gal · New system ≈ $6.9k–$11.1k
Georgia3-bedroom minimum: 1,000 gal · New system ≈ $6.9k–$11.1k
Missouri3-bedroom minimum: 1,000 gal · New system ≈ $6.9k–$11.1k
MichiganSet county by county — no single state number · New system ≈ $7.6k–$12.1k
How states differ
Five of our ten size tanks straight from a bedroom table. Texas sizes from design flow. Florida is the only one that also counts living area. Pennsylvania has no table at all — just a flow formula. Michigan leaves the whole question to its counties. Those differences are exactly why one national chart can't be right, and why each state page here shows its rule's citation next to its numbers.