New Hampshire Irrigation Permit Overview
New Hampshire has no statewide irrigation contractor license. Local municipalities and water utilities set requirements. Manchester, Nashua, Concord, and Derry each have their own processes. The New Hampshire Department of Environmental Services (NHDES) cross-connection program requires backflow prevention. Homeowner self-install is generally allowed with a local permit. Backflow connection may require a licensed plumber. Annual testing required by most utilities under NHDES rules.
Irrigation permit rules in New Hampshire can vary significantly between municipalities. Before starting any irrigation project, contact your local building department and water utility to confirm current permit requirements and backflow device specifications for your address.
Backflow Prevention in New Hampshire
All residential irrigation systems in New Hampshire that connect to a public or private water supply require a backflow prevention device. The device type (PVB minimum) must be installed at the point of connection between your home's water supply and the irrigation system. The backflow preventer must be accessible for inspection and testing, installed above grade, and must not be buried or enclosed in a non-accessible vault.
For more information on device types, see the Backflow Preventer Types Guide. For annual testing requirements, see the Backflow Annual Testing Guide.
How to Get an Irrigation Permit in New Hampshire
- Contact your local building department. Search "[your city or county] building permit irrigation" to find the right office. In New Hampshire, permits are issued at the local municipality level.
- Prepare a site plan. Show your home footprint, zone layout, water connection point, and backflow preventer location. Residential plans don't need to be professionally stamped in most cases.
- Submit your application. Most New Hampshire municipalities now accept online permit applications. Fees for residential irrigation typically range from $50–$250 depending on the jurisdiction.
- Schedule inspections. A final inspection is required after the backflow device is installed and the system is operational. Some jurisdictions also require a trench inspection before backfill.
- Register your backflow device with your water utility if required. Many New Hampshire utilities require backflow device registration within 30 days of installation.
Installing an irrigation system in New Hampshire without the required permit can result in fines, problems during home sales, and insurance claim complications. If you've already installed without a permit, contact your building department about an after-the-fact permit process.
Frequently Asked Questions — New Hampshire Irrigation Permits
In most of New Hampshire, yes — a permit is required for new residential irrigation system installation. Requirements are set at the local municipality level, so the specific process depends on your city or county. Contact your local building department before starting work to confirm the current requirements and permit fee for your address.
Homeowner self-install status in New Hampshire: Generally Available. Even where homeowner self-install is allowed, a permit is still required and the backflow prevention device must meet code requirements. Some jurisdictions in New Hampshire require a licensed plumber for the backflow connection even when homeowner installation of the rest of the system is permitted.
Annual backflow testing requirement in New Hampshire: Annual — NHDES program. Testing must be performed by a certified backflow assembly tester — not just any plumber. Results must typically be submitted to your water utility. Contact your water utility for your specific testing schedule and approved tester list.
The standard backflow device in New Hampshire is: PVB minimum. However, the specific device type required at your address depends on your water utility's cross-connection control program standards. Some utilities require RPZ assemblies as their baseline; others accept PVBs for standard residential irrigation without chemical injection. If you use a fertilizer or pesticide injector, an RPZ is required in virtually all jurisdictions. Confirm with your water utility before purchasing a backflow device.
Related: Homeowner Exemptions by State · Backflow Preventer Types · Permit Cost Guide · Permit Checker Tool