Check Valves & Backflow Prevention
Updated February 24, 2026
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
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.
What to Know
Simple Check Valves
- Spring-loaded, swing, or inline disc types.
- Used for sump pump discharge, recirculation loops.
- Not certified for potable water backflow prevention.
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.
Frequently Asked Questions
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.
What is the bottom line on check valves & backflow prevention?
Check valves for sump pumps and recirculation. Certified backflow preventers for irrigation and cross-connections. Vacuum breakers on all hose bibs.
What's the bottom line on check valves & backflow prevention?
Check valves for sump pumps and recirculation. Certified backflow preventers for irrigation and cross-connections. Vacuum breakers on all hose bibs.
What are the top tips for 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 mistakes should I avoid when buying?
Common mistakes: Simple check valve where certified backflow preventer is required.. Skipping sump pump check valve -- causes short-cycling.. Not testing backflow assemblies annually..
What are the best valves brands?
Top brands include Apollo, Bell & Gossett, BrassCraft, Caleffi, Cash Acme, Danfoss. Each serves different price points and needs.