State guide
New Hampshire
New Hampshire requires prior state approval of sewage disposal system plans through the Department of Environmental Services, while also preserving local authority where municipalities require local sign-off first. The state’s permitting structure relies heavily on permitted subsurface designers, local health officers, and, for property-transfer evaluations, separately licensed septic system evaluators.
Checked against official sources on October 4, 2026. Rules and links change; confirm with the office listed before you act.
- Who regulates septic permits
- New Hampshire DES administers state sewage disposal approvals through its subsurface systems program, but towns may require local approval first and local health officers can receive notices and, in some cases, perform delegated inspections.
- Who can do the soil or perc test
- For design and site work, New Hampshire relies on state-permitted ISDS designers; for transfer evaluations, NHDES says the work must be done by a state-licensed septic system evaluator or, when applicable, a state-permitted septic system designer.
- Official septic permit page
- Official page →
- Licensed evaluators or designers
- Official page →
- State fee
- $450 for each system.
Official resources in New Hampshire
Official state law requiring prior department approval before constructing a sewage disposal system and recognizing local preapproval where required.
State rules for subdivision and individual sewage disposal system design, including permit-by-rule provisions and local health-officer notifications.
Official DES portal referenced by NHDES for searching permitted ISDS designers and installers.
Official state license lookup used to search Septic System Evaluators.
Official NHDES fact sheet explaining waterfront property transfer evaluation rules and how to find evaluators and designers.
Key facts for New Hampshire
- State law says no person may construct a building that will discharge sewage, or construct a sewage disposal system, without prior approval of plans and specifications by DES.
- Applicants must also certify compliance with local wastewater requirements in municipalities that require prior local approval.
- RSA 485-A:34 says soil data from NRCS soils maps supplements information obtained by percolation tests and other independent examination the department may require.
- NHDES says permitted ISDS designers can be searched in SSB OneStop under “Designer And Installer Query.”
- NHDES says septic system evaluators are licensed through OPLC and can be searched in the state license verification system.
- State law sets a $450 fee for each sewage or waste disposal system application or permit by rule.
County septic and soil-evaluation offices in New Hampshire
| County office | city | phone | Details |
|---|---|---|---|
| Town of Holderness Health Officer Grafton | Holderness | 603-968-2145 | Reviews and issues local approvals for septic systems. |
| Town of Moultonborough Code, Compliance & Health Office Carroll | Moultonborough | 603-476-2347 | Town health/code office; local forms and office information used in a lake-area community with many septic-served lots. |
| Town of New Hampton Selectmen’s Office - Septic Designs Belknap | New Hampton | Not published* | Town page explaining local septic design review before submission to the state in a community requiring local approval. |
| Town of Wolfeboro Health Department Carroll | Wolfeboro | 603-569-5970 | Town health department page for septic complaints and DES referral information in a lake-area community. |
| Town of Alton Building & Code / Health Officer Belknap | Alton | Not published* | Town page states the Code Official/Health Officer handles septic design review and pre-approval. |
* Not published: the official page doesn't list it. Call the office to confirm before you rely on it.
What to do next
- Check first whether your town requires local septic approval before you submit to NHDES; some towns do, and DES requires certification of local compliance.
- Use SSB OneStop to identify a permitted designer, and use the OPLC license lookup if you need a licensed septic system evaluator for a transfer or condition evaluation.
- If you are buying waterfront property, read the NHDES transfer fact sheet because it explains when an evaluator alone is enough and when a permitted designer must also be involved.
Not seeing your county office or county?
Not every county office publishes its rules online. Try these, in order:
- General Start with the statewide information above.
- Closest verified Nearest places where we have verified local data outside this state (distance from New Hampshire's population center, for comparison only):
- Board of Health, Massachusetts · about 73 miles
- Public Health Division - Septic System Information, Massachusetts · about 92 miles
- Office of Water Resources OWTS Program, Rhode Island · about 95 miles
- Call to confirm Ask the official office.RSA 485-A:32 Prior Approval; Permits
Website →Phone not shown: use the contact page on the official website above.Your city or county office: Local governments →Not sure who handles it locally? USAGov's free help line, 1-844-872-4681, or the New Hampshire page on USA.gov can point you to the right office. - Know the current info? Tell us with a link to the official page.