Septic companies in New Hampshire

Who Regulates Septic Systems in New Hampshire

Sources: New Hampshire Department of Environmental Services; New Hampshire General Court. Checked 2026-09-18.

New Hampshire approves septic systems from the state. The Department of Environmental Services approves the plans and issues the approvals, and the local layer you deal with is your town rather than your county.

The permitting of individual sewage disposal systems is regulated by the NHDES Subsurface Systems Bureau opens in a new tab, and the statute says no person shall construct any building from which sewage will discharge, or construct a disposal system, without prior approval of the plans and specifications by the department opens in a new tab. Approval of the plans comes before the building, not just before the system.

The town layer is small but real, and it comes first in the order of work. Anyone submitting an application and plans for construction approval shall also certify in writing that they have complied with all local requirements opens in a new tab, and nothing in the statute lessens the powers conferred upon local authorities opens in a new tab. So check the town before you apply to the state.

Inspection is a state job that can be handed to your town. A NHDES inspector will inspect the newly constructed system and evaluate it to ensure it was installed in accordance with the approved plans opens in a new tab, but in cities or towns employing a full time health officer or building inspector, the department may delegate that inspection to them opens in a new tab.

Licenses and What to Check Before You Hire

Sources: New Hampshire Department of Environmental Services; New Hampshire General Court. Checked 2026-09-18.

New Hampshire uses permits for two of these roles and a licence for the third, and they come from two different agencies. Getting the word right matters here, because the evaluator is the one you will need at a waterfront sale and the state does not issue that credential.

The designer and the installer are both permitted by NHDES. NHDES issues ISDS designer permits to individuals who demonstrate a sound working knowledge of the required procedures and practices opens in a new tab, and issues installer permits to individuals who demonstrate a working knowledge of RSA 485-A:29-35 and the ability to read plans opens in a new tab.

You need both, on almost every job. Applications for septic systems must be prepared by a permitted designer, and with the homeowner exception the work must be done by a permitted installer opens in a new tab, and no individual shall engage in the business of installing these systems without first obtaining that permit opens in a new tab.

The exception is narrow and it is about where you live. A person who wants to install a replacement system, or repair one, for their own domicile is not required to hold the permit opens in a new tab. Your own home, not a property you are doing up.

The third credential is a licence and it comes from somewhere else entirely. Septic system evaluators are licensed through the New Hampshire Office of Professional Licensure and Certification opens in a new tab, not by NHDES. Pumping is a permit again: haulers are required to obtain a permit from NHDES to transport sludge and septage in the state opens in a new tab.

We hold no New Hampshire register of our own, so no listing here carries a verified credential for this state. For designers and installers the state points you at OneStop and the Designer and Installer Query opens in a new tab, and an evaluator is checked with the licensing office rather than with NHDES.

Permits, Inspections and Selling a Home

Sources: New Hampshire Department of Environmental Services; New Hampshire General Court. Checked 2026-09-18.

There are two approvals, and you need both before anyone uses the system. After NHDES and, if required, your municipality approve the plans, NHDES issues an Approval for Septic System Construction opens in a new tab, with the operation approval following the build.

Changing the house can mean a new approval even when the system stays put. Prior to expanding any structure or any change in use which would increase the load on a sewage disposal system, the owner shall obtain approval opens in a new tab. Adding a bedroom is the usual trigger.

New Hampshire's point of sale rule applies to waterfront property, and it is the buyer's job rather than the seller's. State law requires septic systems to be inspected at the time of sale for properties within the protected shoreland opens in a new tab, and the buyer of the property shall, at the buyer's expense, engage a New Hampshire licensed septic system evaluator opens in a new tab. The law does not have any requirement for the property seller opens in a new tab.

On an older system the buyer has a second job, and a deadline follows a bad result. The buyer shall also hire a permitted septic system designer to determine the elevation of the bottom of the effluent disposal area opens in a new tab where the approval is old or missing. If the evaluator finds signs of failure, buyers are required to replace the system within 180 days opens in a new tab, though the findings shall not prohibit the sale of the property opens in a new tab.

Keeping a System Working

Sources: New Hampshire Department of Environmental Services; U.S. Environmental Protection Agency. Checked 2026-09-18.

New Hampshire sets a duty rather than an interval: the state requires properties served by an onsite septic system to be operated and maintained to prevent nuisances opens in a new tab, and its advice is that septic tanks should be pumped every three to five years for optimal function opens in a new tab, in line with the EPA's three year inspection guidance opens in a new tab. The binding intervals are local: examples of municipal septic regulations include requiring that systems be pumped once every three years opens in a new tab.

Help Paying for Repairs

Sources: New Hampshire Department of Environmental Services; U.S. Environmental Protection Agency. Checked 2026-09-18.

We found no New Hampshire state fund a household can apply to for a septic repair. The Clean Water State Revolving Fund provides low cost financial assistance for planning, design and construction projects to communities opens in a new tab, which is the wrong shape for one house.

The route that reaches a household is federal, and NHDES links it itself. Section 504 provides loans to very low income homeowners to repair, improve or modernise their homes opens in a new tab, and individual homeowners are not eligible to receive 319 grant assistance directly opens in a new tab.

There is one local exception, and it is worth checking whether your own lake has something similar. The Acton Wakefield Watersheds Alliance and Province Lake Association have funding from a New Hampshire 319 Grant opens in a new tab for septic work in that watershed.

What Your County Does, and Does Not, Do

New Hampshire septic approvals come from NHDES, and no county here runs a septic or environmental health office. We checked every county below and found none. The local layer is your town, whose health officer is appointed under the statute on town health officers, so your town office is the place to ask about local requirements. Checked 2026-09-18.

Questions People Ask