Septic System Regulations in New Hampshire

In New Hampshire, onsite wastewater (septic) systems are regulated by New Hampshire Department of Environmental Services (NHDES), Subsurface Systems Bureau (Water Division), which issues onsite wastewater permits directly. Installing, replacing or repairing a septic system here means, in sequence: a site and soil evaluation, a design, a permit application, an inspection while the system is open, and a final as-built record once it is approved.

counties

with records we hold

records held statewide

Who regulates septic systems in New Hampshire

The state-level regulator is New Hampshire Department of Environmental Services (NHDES), Subsurface Systems Bureau (Water Division) (official program page). NHDES's Subsurface Systems Bureau directly reviews and approves septic (individual sewage disposal system, ISDS) plans and issues both an Approval for Construction and an Approval for Operation statewide; there is no county-level permitting layer. The Bureau processes roughly 6,000 applications per year.

The statewide onsite-wastewater code is cited as RSA 485-A:29-44a and administrative rule Env-Wq 1000 (Subdivisions; Individual Sewage Disposal Systems). We link the agency's own page above rather than restating specific numeric requirements from it, since those change by rule revision and by local amendment.

The permit sequence

The order of operations is broadly consistent across the country, even though the specific numbers in each step vary by state and often by county. None of the figures below are specific to New Hampshire; treat this as the shape of the process, and get the actual numbers from the agency linked above or from the county office.

Site and soil evaluation. A qualified evaluator (see licensing below) digs test pits or runs a percolation test, and records the soil profile, depth to seasonal water table, depth to any restrictive layer, and slope. This determines whether the lot can support a conventional system or needs an alternative design.
Design. Under most state codes, daily design flow is set from bedroom count, not square footage. That flow drives tank capacity, and the soil evaluation sets the drainfield application rate and therefore its size. The designer also lays out setbacks to wells, property lines, surface water, foundations and a reserve/replacement area.
Permit application. Submitted to whichever office issues permits here (state agency or county/district health office, per the delegation model above), along with the design and soil work.
Installation and open inspection. The installer builds the system, and it is inspected before backfill while it is still open to view.
As-built and approval. A final drawing of what was actually built is filed once the system is approved. That as-built is the document a future owner, pumper or inspector needs, and it is what ends up in the county record.

Who can design and install a septic system

Design	NHDES-permitted Septic System Designer (licensed under RSA 485-A:35), who must pass a written exam plus a field test for soil interpretation; plans for proposed septic systems must be designed and submitted by a permitted NH septic system designer.
Installation	NHDES-permitted Septic System (ISDS) Installer (RSA 485-A:36), who must pass a written examination demonstrating knowledge of RSA 485-A:29-35 and the ability to read/understand approved system plans.

Getting septic records in New Hampshire

Septic records in New Hampshire are generally held by the county or local health jurisdiction that issued the permit, not by the state agency, and are released under the state's public records law. We have not logged the specific statute name and response deadline for New Hampshire yet; check with the county office listed on its records page below, or with New Hampshire Department of Environmental Services (NHDES), Subsurface Systems Bureau (Water Division).

Counties in New Hampshire we hold records for

We hold 57 septic records across 1 of 10 New Hampshire counties. Each county page below shows exactly where its records are kept and how many we hold.

County	Records held
Belknap	57

Full New Hampshire county-by-county index · Open the parcel map

Common questions

Who regulates septic systems in New Hampshire?

New Hampshire Department of Environmental Services (NHDES), Subsurface Systems Bureau (Water Division). NHDES's Subsurface Systems Bureau directly reviews and approves septic (individual sewage disposal system, ISDS) plans and issues both an Approval for Construction and an Approval for Operation statewide; there is no county-level permitting layer. The Bureau processes roughly 6,000 applications per year.

What is the septic permit process in New Hampshire?

The sequence is a site and soil evaluation, a design sized from the evaluation and (under most state codes) bedroom count, a permit application, an inspection before backfill, and a final as-built filed once the system is approved. Exact numeric requirements are set by the agency's own code, not restated here.

Who can install a septic system in New Hampshire?

NHDES-permitted Septic System (ISDS) Installer (RSA 485-A:36), who must pass a written examination demonstrating knowledge of RSA 485-A:29-35 and the ability to read/understand approved system plans.

How do I get septic records for a property in New Hampshire?

Septic records are generally held by the county or district health office that issued the permit. See our county-by-county New Hampshire index for the specific office and portal in each county.

Sources

Regulatory information on this page was researched against official state agency sources and last verified 2026-08-31. It is informational only: the agency linked above is authoritative, and requirements can change. We are not lawyers, not a government body, and not affiliated with, licensed or certified by any agency named on this page.