By Granite Trusted Pros · Last updated October 20, 2026
What does every NH seller have to disclose about the septic system?
Under RSA 477:4-c, before any purchase and sale contract for property with a building is signed, the seller must tell the buyer about the sewage disposal system, including:
- the size of the tank and the type of system
- where it is located
- any malfunctions
- the age of the system
- the date it was most recently serviced
- the name of the contractor who services it
The buyer signs a copy to show they received it. If the seller does not know some of this, the law says that fact has to be stated in writing. Pumping receipts are an easy way to answer the "last serviced" and "contractor" questions, so it helps to keep them. Our guide on how often to pump a septic tank in NH covers what NHDES recommends.
When is a septic evaluation required by law?
Since September 1, 2024, RSA 485-A:39 requires a septic system evaluation before the sale of developed waterfront property when any part of the septic system is within 250 feet of the reference line of a waterbody covered by the Shoreland Water Quality Protection Act. NHDES announced the change after House Bill 1113 was signed into law in 2024.
According to the NHDES SSB-14 fact sheet, the protected shoreland includes land within 250 feet of:
- lakes and ponds larger than 10 acres
- fourth-order and larger streams and rivers
- all designated rivers, including smaller sections
- waters subject to the ebb and flow of the tide
NHDES says that if no part of the septic system is within 250 feet of the reference line, nothing is required under this law. If any part is, the whole system is evaluated. The fact sheet points to the NHDES Consolidated List of Waterbodies and its Permit Planning Tool for checking whether a property is in the protected shoreland.
Who pays for the waterfront septic evaluation?
The buyer. RSA 485-A:39 says the buyer engages a New Hampshire licensed septic system evaluator at the buyer's expense. The buyer may accept an evaluation done for the seller if it was completed within 180 days of the transfer, and the buyer has to acknowledge that in writing. NHDES adds that the law puts no requirement on the seller, and the buyer does not have to accept the seller's evaluation.
What if the septic system is old or has no state approval?
For waterfront property covered by the law, if the system was never approved by NHDES, or its approval is dated before September 1, 1989, the buyer must also hire a state-permitted septic system designer. The designer finds the bottom of the leach field (the law calls it the effluent disposal area) compared to the seasonal high water table and decides whether the system is in failure. NHDES says this usually means digging a test pit beside the leach field. This has to be done before the sale closes.
What happens if the evaluation finds a problem?
The findings do not stop the sale, but they must be disclosed to the buyer. If the evaluator finds signs of failure, or the designer finds the system is in failure, RSA 485-A:39 says:
- the buyer signs a document letting the evaluator notify NHDES and the local health officer
- the evaluator notifies NHDES and the local health officer
- the buyer replaces the system within 180 days of the transfer
- the buyer files a report, with a copy of the state approval for operation of the new system, with NHDES and the local health officer
A buyer who already plans to replace the system can skip the evaluation by replacing or repairing it within 180 days of the transfer, as long as they notify NHDES and the local health officer before the sale. If circumstances beyond the buyer's control get in the way, NHDES will grant an extension of up to 180 days on request.
Does a home that is not on the water need a septic inspection to sell?
The state evaluation rule in RSA 485-A:39 applies only to waterfront property within the 250 foot zone. Even so, NHDES notes that home and septic inspections are part of most real estate transactions in New Hampshire, so many buyers ask for one. NHDES also tells evaluators to check local ordinances, so ask your town's health officer or building department whether your town has rules of its own.
How do I find the records for my septic system?
NHDES keeps septic system records in its Subsurface OneStop portal, which you can search by owner name, address, designer, installer or approval number. Online records cover 1967 to 1986 and 2016 to the present, and records from 1986 to 2016 are still being digitized. If you cannot find yours, NHDES takes archive requests, and your town may have copies too. A septic system needs both an Approval for Construction and an Approval for Operation from NHDES before it can be used, so those are the two documents to look for.
Who is allowed to do a septic evaluation in NH?
NHDES says septic system evaluators are licensed through the NH Office of Professional Licensure and Certification (OPLC), and you can find them on the New Hampshire Online Licensing site by choosing "Septic System Evaluators." Permitted septic designers can be searched in NHDES OneStop. NHDES also says the words "inspection" and "evaluation" tend to be used interchangeably; for waterfront sales, what matters is that the work is done by a state-licensed evaluator using board-approved standards.
Where can I find septic pros near me?
Our septic service directory lists local septic companies in Milford, Nashua, Bedford, Merrimack, Amherst, Manchester, Concord and nearby towns, with phone numbers you can call directly. Before you book, ask the company which state license it holds for your job, such as septic system evaluator, septic designer or septage hauler.
Frequently asked questions
Do I need a septic inspection to sell my house in NH?
State law requires a septic evaluation only for developed waterfront property where any part of the septic system is within 250 feet of the reference line of a protected waterbody (RSA 485-A:39). Every seller must still disclose what they know about the system under RSA 477:4-c, and NHDES notes that home and septic inspections are part of most real estate transactions in New Hampshire.
Who pays for the septic evaluation on NH waterfront property?
The buyer, at the buyer's expense, under RSA 485-A:39. The buyer may accept an evaluation done for the seller by a licensed evaluator if it was completed within 180 days of the transfer and the buyer acknowledges it in writing.
What does a NH seller have to disclose about the septic system?
Under RSA 477:4-c, the size of the tank, the type of system, its location, any malfunctions, the age of the system, the date it was last serviced, and the name of the contractor who services it. If the seller does not know something, that has to be stated in writing.
Can a house in NH be sold if the septic system is failing?
Yes. RSA 485-A:39 says the evaluator's or designer's findings do not prohibit the sale. For waterfront property covered by the law, if the system shows signs of failure, the buyer must replace it within 180 days of the transfer.
Is a septic evaluation the same as a septic inspection?
NHDES says the two terms tend to be used interchangeably. For waterfront transfers, the law is met when the work is done by a septic system evaluator licensed by the State of New Hampshire using board-approved standards.
Sources
- NH RSA 477:4-c, Disclosure Required; Water Supply; Sewage Disposal
- NH RSA 485-A:39, Waterfront Property Transfer; Septic System Evaluation Required
- NHDES fact sheet SSB-14, Transfers of Waterfront Properties with Septic Systems in the Protected Shoreland
- NHDES: Waterfront property transfers now require septic evaluations (Sept. 6, 2024)
- NHDES: Septic Systems
- NHDES: Get Pumped! New Hampshire
This guide is general information, not legal advice. Laws and rules change, so talk to your real estate attorney, agent or a licensed septic professional about your own sale.