How to Replace Plastic Water Heater Drain Valves to Prevent Leaks and Flood Damage

Many water heaters are sold with an inexpensive plastic drain valve. Over time these valves deteriorate and may eventually fail either by developing a leak after draining the tank, or by being broken off by accident.

Replace your valve today to avoid costly damage and cold showers.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Wrenches, adjustable, pipe, or open end/combo to fit valves.
• Teflon pipe tape or liquid thread sealant
• Bucket or short hose.
• Brass boiler drain valve in appropriate thread.

1. Turn off water heater power supply,
   If electric this would be the breaker in your electrical panel.
   If gas powered you will need to turn off the gas supply, refer to instructions on your hot water heater. (Note: For gas water heaters you will need to reignite your hot water heater later, this can be hazardous if done improperly, if you are uncomfortable with this contact a plumber.) Heat must be off to continue.

2. Turn off water supply to water heater, often a valve will be installed above tank to allow easy service, if not you may need to shut off the main water supply.

3. Open hot water valves on nearest sink and run until flow stops leave valve open for later.

4. Locate plastic water drain valve on tank, position bucket or install a short segment of hose run to a drain. Open valve and allow tank to drain. Use caution, water may be hot.

5. Remove plastic drain valve. (inspect for sediment flush if necessary)

6. Install new boiler tank valve using Teflon thread sealant tape or liquid brush on thread sealant. Close new drain valve.

7. Turn on water supply and allow water to fill tank. (If you shut the valve you used to drain tank open it to allow air to escape tank, close valve when full)

8. Inspect for leaks, then turn on power at electrical panel, or reignite gas following instructions on water heater.

Tips & Warnings

• Flush tank regularly, sediment can build up and reduce water tank volume and efficiency. I use mine to fill buckets for cleaning, this accomplishes a regular flush with out needing new steps.
• New valve needs to be constructed of brass, or it can contribute to rust formation in your tank (some are plastic or glass lined to prevent this).
• If you are reading this because you already broke a valve and flooded your basement or ruined your floors, then you have a stub of broken plastic. The stub can be chipped out, and then a tap run through the threads to clean them up of bits of plastic and sealant.
• Water in tank may be scalding, to prevent burns you may choose to run the hot water after turning off the heat source until the water cools to a comfortable level.
• Remove plastic valve carefully, they do break fairly easily when old.