Sprinkler repair guide

Backflow Preventer Repair

Brass pressure vacuum breaker backflow preventer with blue-handled ball valves on insulated pipe against a stucco wall
On this page 9 sections
  1. Signs You May Need This Repair
  2. Common Causes
  3. How a Technician Handles It
  4. Repair or Replace?
  5. DIY or Call a Pro?
  6. Typical Cost
  7. Related Problems
  8. Frequently Asked Questions
  9. Bottom Line

The backflow preventer keeps irrigation water from flowing back into the drinking water supply.

Repair usually involves replacing worn internal parts or the whole device, followed by testing where required.

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Signs You May Need This Repair

  • Water leaking or spraying from the device
  • Water discharging from a relief port
  • Cracked body
  • Low system pressure

Common Causes

  • Worn internal parts
  • Debris
  • Freeze damage
  • Pressure changes
Above-ground backflow preventer assembly with brass test cocks and shut-off valvesPhoto: Mds08011, CC BY 4.0

How a Technician Handles It

  1. Inspect the device
  2. Shut off water
  3. Replace worn parts or the device
  4. Test where required
  5. Restore water and check for leaks

Repair or Replace?

Worn parts are often replaced. Cracked or badly damaged devices are usually replaced.

DIY or Call a Pro?

Because the device protects drinking water and local rules may apply, backflow repair and testing should be done by a qualified professional.

Stay safe: stick to settings, visual checks and closing the irrigation shutoff. Don’t open valves or fittings under pressure, and leave electrical testing to a professional.

Typical Cost

See our Backflow Repair Cost Guide for typical ranges. Prices vary by location, parts, access and how much diagnosis is needed.

Related Repairs

Frequently Asked Questions

Why is my backflow preventer leaking?

Worn parts, debris, pressure changes or freeze damage.

Can a backflow preventer be repaired?

Often, by replacing internal parts.

Is backflow testing required?

Requirements vary by area. Check with your local water provider.

Bottom Line

Backflow repair protects both the irrigation system and the drinking water supply. A qualified professional can repair or replace the device and handle any required testing.

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