Backflow Preventer Leaking in Arlington? Causes, Fixes and Costs

A backflow preventer usually leaks because of freeze damage, worn rubber seals or checks, a loose test cock or bonnet, debris stuck in a check valve, or high water pressure. A small drip can often be fixed with new seals. A cracked body from a freeze usually means replacing the assembly. Shut the valve on the supply side first, then call (817) 285-5426 if it keeps leaking.

Not sure the leak is at the backflow at all? Our leak detection Arlington TX team checks the whole irrigation and water line.

What does a backflow preventer do?

A backflow preventer stops water from your sprinkler system, which can carry fertilizer and soil, from flowing back into the drinking water supply. Texas rules require one on lawn sprinkler systems. Most Arlington homes use a pressure vacuum breaker or a double check assembly near the house or in a box by the meter.

What are the 5 common causes of a leak?

1. Freeze damage. Exposed brass and plastic parts crack in hard freezes. A split body or bonnet sprays water when the system turns on.
2. Worn seals. Rubber seats and O-rings harden with age and Texas heat.
3. Loose test cocks or bonnet. The small valves used for testing can drip if not fully closed.
4. Debris in a check. Sand or a small rock can hold a check valve open and cause a steady drip or spit.
5. High water pressure. Pressure spikes wear parts faster and can cause the relief port to discharge.

What should you do first?

1. Turn off the sprinkler controller so the system stops calling for water.
2. Close the shut-off valve on the supply side of the backflow preventer.
3. If water still runs, close the main shut-off for the house. See main shut-off valve.
4. Take a photo of the leak and the brand and size printed on the valve.

How do you protect it from freezing?

• Shut off the supply valve and drain the device before a hard freeze.
• Open the test cocks a quarter turn to let water out.
• Wrap it with an insulated cover or bag made for backflow devices.
• Read our guide to prevent frozen pipes for the rest of the house.

Can a backflow preventer be repaired, or must it be replaced?

Many leaks can be repaired. Worn seals, checks and test cocks come in repair kits for most common brands, and a repair keeps the existing pipe connections. A body or bonnet that cracked in a freeze usually means a new assembly. After any repair or replacement, the device should be tested by a licensed backflow tester so it is known to protect the water supply.

• Repair: steady drip from a relief port, a loose bonnet, or a worn test cock.
• Replace: split brass, a cracked plastic bonnet, or a very old device with parts no longer made.
• Test: many Texas water systems ask for a test after install or repair. Ask the City of Arlington water utility what applies to your home.

Is the leak at the backflow or somewhere else?

If you see water at the device, the leak is there. If the yard is soggy elsewhere or the meter moves with the sprinklers off, the leak may be in a buried irrigation or service line. That needs leak detection, which runs about $150 to $400 for a basic visit and $200 to $500 for a water line.

General estimates for Arlington, TX in 2026. Your exact price is confirmed before any work begins.

Our sprinkler and irrigation leak guide and underground water line guide explain how we trace those leaks.