All 50 states
Septic requirements, state by state
The same three-bedroom house needs a 750 gallon tank in Tennessee and a 1,500 gallon tank in Ohio and Massachusetts. Here is every state's rule, with the citation.
50 states
| State | 3-BR tank | 4-BR tank | Design flow | Well setback | Permit fee | Typical install | Permitted by |
|---|---|---|---|---|---|---|---|
| Alabama | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $150–$500 | $5,500–$14,000 | County |
| Alaska | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $250–$900 | $14,000–$38,000 | Both |
| Arizona | 1,000 gal | 1,500 gal | 150 gpd/BR | 100 ft | $300–$1,200 | $7,000–$19,000 | County |
| Arkansas | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $150–$400 | $5,000–$13,000 | State |
| California | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $500–$3,000 | $15,000–$45,000 | County |
| Colorado | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $300–$1,500 | $12,000–$32,000 | County |
| Connecticut | 1,000 gal | 1,250 gal | 150 gpd/BR | 75 ft | $250–$900 | $14,000–$35,000 | County |
| Delaware | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $200–$700 | $9,000–$26,000 | State |
| Florida | 1,000 gal | 1,250 gal | 100 gpd/BR | 75 ft | $300–$1,100 | $7,000–$20,000 | Both |
| Georgia | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $150–$600 | $6,000–$16,000 | County |
| Hawaii | 1,000 gal | 1,000 gal | 75 gpd/BR | 50 ft | $300–$1,200 | $18,000–$48,000 | State |
| Idaho | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $250–$800 | $8,000–$22,000 | County |
| Illinois | 1,000 gal | 1,250 gal | 150 gpd/BR | 75 ft | $150–$700 | $9,000–$24,000 | County |
| Indiana | 1,000 gal | 1,250 gal | 150 gpd/BR | 50 ft | $150–$600 | $8,000–$21,000 | County |
| Iowa | 1,250 gal | 1,250 gal | 150 gpd/BR | 100 ft | $150–$500 | $9,000–$23,000 | County |
| Kansas | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $100–$500 | $6,500–$17,000 | County |
| Kentucky | 1,000 gal | 1,250 gal | 110 gpd/BR | 70 ft | $150–$500 | $6,500–$17,000 | County |
| Louisiana | 1,250 gal | 1,500 gal | 150 gpd/BR | 100 ft | $100–$400 | $5,500–$15,000 | State |
| Maine | 1,000 gal | 1,250 gal | 90 gpd/BR | 100 ft | $250–$700 | $10,000–$26,000 | County |
| Maryland | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $300–$1,200 | $12,000–$34,000 | County |
| Massachusetts | 1,500 gal | 1,500 gal | 110 gpd/BR | 100 ft | $300–$1,500 | $18,000–$45,000 | County |
| Michigan | 1,000 gal | 1,250 gal | 150 gpd/BR | 50 ft | $200–$900 | $8,000–$22,000 | County |
| Minnesota | 1,000 gal | 1,500 gal | 150 gpd/BR | 50 ft | $250–$900 | $12,000–$30,000 | County |
| Mississippi | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $100–$400 | $5,000–$14,000 | State |
| Missouri | 1,000 gal | 1,250 gal | 120 gpd/BR | 100 ft | $150–$600 | $7,000–$19,000 | Both |
| Montana | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $200–$900 | $9,000–$26,000 | County |
| Nebraska | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $100–$400 | $6,500–$18,000 | State |
| Nevada | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $300–$1,200 | $9,000–$25,000 | County |
| New Hampshire | 1,250 gal | 1,250 gal | 150 gpd/BR | 75 ft | $300–$900 | $12,000–$30,000 | State |
| New Jersey | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $400–$1,500 | $16,000–$42,000 | County |
| New Mexico | 1,250 gal | 1,500 gal | 150 gpd/BR | 100 ft | $150–$500 | $7,000–$19,000 | State |
| New York | 1,000 gal | 1,250 gal | 110 gpd/BR | 100 ft | $250–$1,200 | $14,000–$38,000 | County |
| North Carolina | 1,000 gal | 1,000 gal | 120 gpd/BR | 100 ft | $300–$900 | $6,500–$18,000 | County |
| North Dakota | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $100–$400 | $8,000–$21,000 | County |
| Ohio | 1,500 gal | 2,000 gal | 120 gpd/BR | 100 ft | $300–$1,000 | $9,000–$26,000 | County |
| Oklahoma | 1,000 gal | 1,000 gal | 100 gpd/BR | 50 ft | $100–$400 | $5,500–$15,000 | State |
| Oregon | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $500–$2,000 | $12,000–$32,000 | Both |
| Pennsylvania | 1,000 gal | 1,250 gal | 100 gpd/BR | 100 ft | $300–$1,200 | $10,000–$28,000 | County |
| Rhode Island | 1,000 gal | 1,000 gal | 115 gpd/BR | 100 ft | $400–$1,200 | $15,000–$38,000 | State |
| South Carolina | 1,000 gal | 1,000 gal | 150 gpd/BR | 100 ft | $150–$500 | $6,000–$16,000 | State |
| South Dakota | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $100–$400 | $7,000–$19,000 | County |
| Tennessee | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $200–$600 | $6,000–$17,000 | State |
| Texas | 1,000 gal | 1,250 gal | 75 gpd/BR | 100 ft | $250–$900 | $6,000–$18,000 | County |
| Utah | 1,000 gal | 1,000 gal | 150 gpd/BR | 100 ft | $250–$900 | $8,000–$22,000 | County |
| Vermont | 1,250 gal | 1,500 gal | 140 gpd/BR | 100 ft | $300–$1,000 | $12,000–$30,000 | State |
| Virginia | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $300–$900 | $8,000–$22,000 | County |
| Washington | 1,000 gal | 1,000 gal | 120 gpd/BR | 100 ft | $400–$1,500 | $14,000–$36,000 | County |
| West Virginia | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $100–$400 | $6,500–$18,000 | County |
| Wisconsin | 1,000 gal | 1,500 gal | 150 gpd/BR | 50 ft | $300–$1,000 | $10,000–$27,000 | County |
| Wyoming | 1,000 gal | 1,250 gal | 150 gpd/BR | 100 ft | $100–$500 | $8,000–$21,000 | Both |
Tank figures are the governing requirement rounded up to a stock size, combining each state's bedroom table and detention rule. Open a state for the citation.
Why state rules differ this much
Septic code is written at state level and administered, in most of the country, by counties. There is no federal septic code — the EPA publishes guidance and model standards, but nothing binding on a homeowner. The result is fifty genuinely different rulebooks, shaped by three things:
- Geology and climate. Minnesota writes for frost and Florida writes for a water table two feet down. Both are correct for where they are.
- Water quality politics. The Chesapeake Bay, Puget Sound, Long Island's aquifer, and Hawaii's reefs have each driven rules far stricter than the surrounding region.
- When the code was last rewritten. States that updated recently — North Carolina, Florida — tend to have performance-based rules. States running on older codes lean on prescriptive tables.
Where the real authority sits
For most readers the state rule is a floor, not the answer. 37 of the 50 states delegate permitting to counties or local health districts, and those bodies can and do impose stricter requirements. Michigan goes furthest — it has no statewide onsite code at all, so the county ordinance is the law. California is similar in effect: the state sets an OWTS Policy and each county's Local Agency Management Program fills in the detail.
Start with your state page here to understand the framework and the numbers, then call the county. That order saves a phone call you do not know how to have yet.