What should I look for when buying check valves & backflow prevention?

Spring-loaded check valve on sump pump prevents loud clank when pump cycles off. Replace sump pump check valves every 5-7 years. Hose bib vacuum breakers ($3-5) are cheapest backflow protection.

What are common mistakes when buying check valves & backflow prevention?

Simple check valve where certified backflow preventer is required. Skipping sump pump check valve -- causes short-cycling. Not testing backflow assemblies annually.

Check Valves & Backflow Prevention

Buying Guide

Created by Ryan Pietrzak Illinois Licensed Plumber · In the plumbing industry since 2009

Updated February 20, 2026

Key Takeaway

Backflow occurs when contaminated water flows backward into clean supply. Check valves and backflow preventers allow water to flow one direction only. Different applications require different devices.

Overview

What to Know

Simple Check Valves

One-way valves. Spring-loaded, swing, or inline disc types. Used for sump pump discharge, recirculation loops. Not certified for potable water backflow prevention. $5-25.

Backflow Prevention Assemblies

Certified devices for potable water protection. RPZ assemblies for highest protection. Vacuum breakers for irrigation. Annual testing required by most jurisdictions.

Residential Requirements

Most homes need: check valve on sump pump, vacuum breaker on hose bibs, backflow preventer on irrigation system. Check local code.

Buying Tips

Spring-loaded check valve on sump pump prevents loud clank when pump cycles off.
Replace sump pump check valves every 5-7 years.
Hose bib vacuum breakers ($3-5) are cheapest backflow protection.
Verify irrigation system has code-compliant backflow preventer.

Common Mistakes

Simple check valve where certified backflow preventer is required.
Skipping sump pump check valve -- causes short-cycling.
Not testing backflow assemblies annually.
Removing hose bib vacuum breakers because they drip -- dripping is by design.

Bottom Line

Check valves for sump pumps and recirculation. Certified backflow preventers for irrigation and cross-connections. Vacuum breakers on all hose bibs.