Septic tank size by state / Mid-Atlantic
New York septic tank size
In New York the minimum septic tank for a three-bedroom house is 1,000 gallons, rising to 1,250 gallons at four bedrooms. The figure comes from 10 NYCRR Appendix 75-A.6 (Septic tanks and enhanced treatment units), Table 3. That matches the 1,000-gallon median of the 47 states listed here.
What the New York rule says
The rule is 10 NYCRR Appendix 75-A.6 (Septic tanks and enhanced treatment units), Table 3, administered by New York State Department of Health (local health departments administer; NYC, Suffolk and Nassau have their own standards). In its own words:
Table 3 Minimum Septic Tank Capacities: "1,2,3 1,000 27"; "4 1,250 34"; "5 1,500 40"; "6 1,750 47" (gallons, sq ft). "NOTE: Tank size requirements for more than six bedrooms shall be calculated by adding 250 gallons and seven square feet of surface area for each additional bedroom." "A garbage grinder shall be considered equivalent to an additional bedroom for determining tank size."
Source: 10 NYCRR Appendix 75-A.6 (Septic tanks and enhanced treatment units), Table 3, read 2026-10-20.
- A garbage grinder counts as one extra bedroom: three bedrooms plus a grinder need 1,250 gallons.
- New York City, Suffolk and Nassau counties have their own standards.
New York minimum tank size by bedrooms
| Bedrooms | Minimum tank | Versus the median state |
|---|---|---|
| 1 | 1,000 gal | same |
| 2 | 1,000 gal | — |
| 3 | 1,000 gal | same |
| 4 | 1,250 gal | +50 |
| 5 | 1,500 gal | same |
| 6 | 1,750 gal | — |
The first step up comes at 4 bedrooms, from 1,000 to 1,250 gallons, and a six-bedroom house needs 1,750 gallons. Beyond the table the rule adds 250 gallons for each extra bedroom. These are minimums: the permit can call for more, and a bigger tank needs pumping less often.
How New York compares with nearby states
New Jersey requires 1,000 gallons for three bedrooms; Pennsylvania requires 900 gallons for three bedrooms. 37 of the 47 states listed here share New York's three-bedroom figure.
Before you size a tank in New York
- Bedrooms, not people, set the size in most rules. Rooms that could be used as bedrooms are usually counted, so check how your permitting office counts a den or a finished basement.
- Garbage disposals, grinder or ejector pumps and large tubs change the answer in many states; the points above list New York's adjustments.
- The tank is only half the system. The drainfield is sized separately from soil tests, and it is usually the bigger cost.
- A private well on the same lot has its own setbacks from the tank and field; the well pump and pressure tank calculators size the water side.
Figures are the state's minimum as written on 2026-10-20. Local health departments can require more; the permit issued for your property governs. See the methodology for how each state was read.