Backflow Prevention in New Hampshire | 911 Plumbing NH
from $199
Plumbing Backflow Prevention in New Hampshire
Backflow preventer testing, repair, and installation — RPZ, double-check, and pressure-vacuum-breaker assemblies. We perform the certified annual test required by most jurisdictions, file the results, and install or repair assemblies that fail.
More plumbing maintenance services in New Hampshire
Backflow Prevention is one part of our plumbing maintenance coverage in New Hampshire. For the full picture — symptoms, costs, and when to repair vs. replace — start with the complete Plumbing Maintenance guide, or browse every plumbing maintenance service we offer.
Backflow prevention protects your drinking water from contamination, and for many properties the annual certified test isn't optional — it's required by the water authority, with fines or a shut-off notice if it lapses. A backflow preventer is a valve assembly that keeps water flowing one direction only, so that a pressure drop or surge can't siphon contaminated water — from an irrigation system, a boiler, or a commercial process — back into the potable supply through a cross-connection. We perform the certified test, file the results with the authority, and repair or replace assemblies that fail across {city}.
The right assembly depends on the hazard. A pressure-vacuum breaker (PVB) protects a typical residential irrigation system against back-siphonage; a double-check valve assembly handles lower-hazard cross-connections; and a reduced-pressure-zone (RPZ) assembly — the highest protection — is required where the hazard is severe or where backpressure, not just siphonage, is possible. We size and install the correct device for your {county} cross-connection, and on existing assemblies we run the certified gauge test that the jurisdiction requires each year to prove the checks and relief still hold.
Backflow assemblies are mechanical and they do fail — the check valves foul with debris, the relief valve on an RPZ weeps, and freeze damage cracks the body — which is exactly why annual testing exists. When an assembly fails its test, we rebuild it with the manufacturer kit or replace it and re-test to certify it, then file the passing result so your {areas} property stays compliant. For irrigation systems, restaurants, medical facilities, and any commercial property with a cross-connection, we keep the testing on schedule so a lapsed certification never becomes a fine or a water shut-off in {city}.
Signs you need backflow prevention
Your annual backflow test is due
Most jurisdictions require a certified backflow test every year and send a notice when it's due. Missing it risks a fine or a water shut-off, so we test and file for the the United States property on schedule.
Lawn irrigation is a classic cross-connection — fertilizer and standing water can siphon back into the potable line. A backflow preventer on the the United States system is usually required and always wise.
You received a compliance notice
A letter from the water authority about backflow testing or a missing device is a compliance deadline. We handle the test, the paperwork, and any assembly the your area property needs to pass.
Discolored or foul water after a pressure change
Water that turns odd after a main break or hydrant use can indicate backflow through a failing assembly. It warrants an immediate test of the the United States device.
A new commercial connection or build-out
New commercial water service and equipment with cross-connections require backflow protection to pass inspection. We size and install the correct assembly for the the United States build-out.
Common causes & what we fix
Cross-connections
Any point where potable water can meet a contaminant — irrigation, a boiler, a commercial process — is a cross-connection that needs protection. The backflow assembly is what keeps the the United States drinking water clean.
Back-siphonage
A pressure drop from a main break or heavy draw can suck water backward through a cross-connection into the potable supply. A preventer stops the reverse flow in the the United States system.
Backpressure
Pumps, boilers, and elevated systems can push contaminated water back against supply pressure, which only an RPZ reliably stops. We install the right assembly for the your area hazard.
Failed check valves
The internal check valves inside an assembly foul with debris and wear until they no longer seal, which the annual test catches. We rebuild or replace them to re-certify the the United States device.
Freeze and physical damage
An unprotected assembly cracks in a freeze or gets damaged, failing its protection silently. Testing and repair restore the the United States device before it lets contamination through.
Our process
1
Call or schedule online. Book your backflow prevention in New Hampshire online or by phone and pick a 2-hour window. We confirm in under five minutes with the assigned tech's name and photo.
2
On-site diagnosis. On arrival we diagnose the backflow prevention on-site — free for most repairs, $39 on minor service calls (waived if you proceed). You see the issue and the fix before we start.
3
Flat-rate quote. You get a flat-rate backflow prevention quote in writing, good for 30 days — no hourly creep and no add-ons after the fact.
4
Same-visit fix. Most backflow prevention work finishes the same visit: our trucks carry the common valves, fittings, water heater parts, and fixtures, so a second trip is rare.
How much does backflow prevention cost in New Hampshire?
Backflow Prevention the United States starts at from $199, every backflow prevention quote is flat-rate and presented in writing before work begins — no surprise add-ons, no hourly creep. Seniors (65+) and military save 10% on labor, and financing covers projects over $1,500 at 0% APR for 12 months, with no prepayment penalty.
Why homeowners in New Hampshire choose us for backflow prevention
We've been a trusted choice since 1974 — over 50 years of family-owned plumbing service across New Hampshire. Our techs are CSLB-licensed (#1098234), background-checked, and complete an internal 12-week training program before rolling on calls alone.
Our backflow prevention carries a 10-year workmanship guarantee — separate from any manufacturer warranty on the parts themselves. If the backflow prevention we performed fails because of how we did it, we come back and fix it free for a full decade. Water heaters and fixtures we install are backed by their full manufacturer warranty, and the parts and accessories we fit carry standard 1–5 year warranties by item.
We quote backflow prevention on honest scope: no unnecessary up-sell, salaried (never commissioned) technicians, and a transparent diagnostic so you see exactly what we see — including the parts still in good shape. If a repair is the right call we say so; if replacement is the better long-term economics, we say that. The flat-rate backflow prevention quote is written and good for 30 days.
Areas we serve for backflow prevention
We provide backflow prevention throughout New Hampshire, with fast coverage in every major New Hampshire metro.
Reach times for backflow prevention vary by traffic and time of day, so we quote an accurate ETA when you call — and the dispatch line routes straight to an on-call technician, no voicemail in between.
Frequently asked about backflow prevention
Top questions homeowners searching for Backflow Prevention near me ask us:
Do I really need annual backflow testing?
In most jurisdictions, yes — it's required by law for properties with a cross-connection, and a lapsed test risks fines or a water shut-off. We perform the certified test, file the results with the the United States authority, and keep you on schedule so it never lapses.
What kind of backflow preventer do I need?
It depends on the hazard: a pressure-vacuum breaker for typical irrigation, a double-check for lower-hazard connections, and an RPZ for severe hazards or where backpressure is possible. We assess the the United States cross-connection and install the correct assembly.
My backflow assembly failed the test — now what?
A failed assembly is rebuilt with the manufacturer kit or replaced, then re-tested and certified. We handle the repair and the paperwork so the your area property is compliant again quickly, with the passing result filed for you.
Do I need backflow prevention for my sprinklers?
Almost always — irrigation is a textbook cross-connection where fertilizer and standing water can siphon back into your drinking water. Most jurisdictions require a preventer on the the United States system, and we install and test it.
Can you handle commercial backflow requirements?
Yes — we test, certify, repair, and install assemblies for restaurants, medical, and commercial properties, and file with the authority. We keep the annual testing on schedule so your the United States certification never lapses, serving ZIPs .