State rules, checked line by line
What size septic tank does your state require?
Pick your state. Every answer below comes from that state's own published rule — with the citation and a link to the official text, checked Nov 10, 2026. No national chart with the state name swapped in.
Septic tank size calculator
State rules we've checked
Ten states, read from the official code — not copied from another calculator. Each state page shows the full table, the rule citation, and what a typical system costs there.
Before you dig: the two bills that come first
Questions everyone asks
How many bedrooms will a 1,000-gallon septic tank support?
It depends on the state — that is the honest answer. In New York and North Carolina a 1,000-gallon tank covers up to 3–4 bedrooms by the rulebook; in Ohio it only covers 1–2 bedrooms, because Ohio's table starts bigger. Pick your state in the calculator above and you will get your state's own number, with the rule it came from.
How much is a septic tank for a 2,000 sq ft house?
Square footage only enters the math in Florida, where the rule sizes by bedrooms AND living area together: a 3-bedroom, 2,000 sq ft Florida home needs 1,050 gallons. Everywhere else the permit is written against bedroom count, not floor area — but the full system cost for a typical 3-bedroom home runs roughly $7,600–$12,100 installed by our line-by-line estimate.
Does a garbage disposal really require a bigger tank?
In some states, yes — and the rule is different in each. Georgia multiplies the tank by 1.5, Florida adds a flat 250 gallons, New York counts the disposal as one extra bedroom, North Carolina multiplies by 1.5 — while Pennsylvania and Missouri already include disposals in their design flows and add nothing, and Virginia's tank rule doesn't mention disposals at all. Any chart that applies one '+50%' column to every state is wrong in most of them.
Why do states require such different tank sizes?
Each state wrote its rule around its own soils, water tables and housing stock, and they picked different math: Texas sizes from design flow, Florida from bedrooms plus living area, Pennsylvania from a flow formula, Michigan leaves it to counties. The spread is real — a 3-bedroom minimum runs from 900 gallons (Virginia, Florida small homes) to 1,500 gallons (Ohio).
Can my county require a bigger tank than the state minimum?
Yes, and it often does. State rules are floors. County health departments issue the permit and can set stricter local rules — in Michigan the county rule is the only rule. Always confirm the final number with your local health department before you order a tank.
Why this site shows its work
We checked the charts other calculators publish against the official rules, state by state. In the first nine states we compared, not one state's table matched its own rulebook in full — and two different states were shown the exact same table. Every number here carries the rule it came from and the date we checked it. See how we check →
Get an email if your state's rule changes
Septic rules change rarely — North Carolina rewrote its rules in 2024, Pennsylvania has a revision in draft. If your state's rule changes, we will email you once, with what changed. No newsletter, no spam.
Alerts start once email delivery is switched on; the form opens in our form provider. One email per rule change, unsubscribe in every email.