You will need to know how to drain a hot water heater if you ever need to replace heating elements, a thermocouple or a unit itself.
There is no need to call a plumber for this simple DIY job, unless you are out of your comfort zone. Keep in mind, you never need to drain instantaneous water heaters – there is nothing to drain, except your savings account if you ever think it will stop.
Warning: Never work on electricity or gas water heaters if you are unsure of your abilities and know what you are doing.
The first step to tackling any hot water heater problem is to turn off the electricity or, if gas fueled tanks, turn down the heat to only a pilot light. Always test the power to be safe.
Multi-meter (if electric)
Garden hose or bucket
Turn Off Energy Source
If you have an electric water heater, it is probably on a dedicated circuit on your electric panel. Locate your panel, and flip the breaker switch to “off”. Even if there is an in-line switch near the water heater, it’s always a good idea to flip the breaker.
Once completed, test the wires with a voltmeter or multi-meter where the electric wires meet the water heater.
For gas powered water heaters, you need to locate the control knob. Take note of where the knob is located, you can use a sharpie or a piece of tape to mark its location. Make sure you turn it all the way down to the pilot light. If you pilot light goes out, re-light it with a match. If there is a spark plug ignition, go ahead and press the button until it lights.
Turn Off Water Supply
Locate your water shut off valve that supplies your water heater. It will be a on “cold” water line. Once located, turn it to the off position.
Open a Faucet and Drain Hot Water Heater
The easiest (and quickest) way to drain your water heater is by opening your tub faucet to the “hot” position. Anytime you drain a water heater, sediment flows through the pipes and can get stuck in flow restrictors like shower heads or sink faucet aerators. Tub faucets do not have flow restrictors so any sediment will not cause you any clogging problems. If you do not have a tub spigot, you can use another faucet. Just make sure to remove the flow restrictor first.
As you drain the water heater, periodically check the water to make sure it is still hot or warm so you aren’t continuously draining cold water from your well or utility company.
For most issues, that’s all you need to do. After you drain a hot water heater, do the same steps in reverse. Close the tub faucet, open the water supply valve and turn your electricity back on or the gas control knob back to its original location.
If you need to do a complete empty, there are a few more steps to follow.
Water heaters that have not had a complete drain in years, the drain valve may clog from sediment at the bottom of the tank. Be prepared with a spare valve, just in case along with your bucket and towels.
Water heaters have drain valves near the bottom of the tank. If your water heater has a garden hose thread, you are in luck! Attach that hose to the valve and take the other end outside.
Drain valves come in a variety of types and some can be quite frustrating. Plastic drain valves are horrible. Whomever came up with the idea was more concerned with saving on manufacturing costs than designing a water heater for longevity. If you have a plastic drain valve, I urge you to consider replacing it with a brass valve.
Over time, heat causes plastic to harden and become brittle. Do not want to run into a situation where the drain valve gives out and floods your home.
If your current valve has a handle all you need to do is turn it open. Other valves may have a twist knob or even a flathead screw that needs to be turned. Whatever it is, open it and watch the sediment flow out of your water heater.
If your valve does not have a garden hose attachment, you will be stuck with your bucket and making trips to empty it until the water heater is completely emptied.
If there’s a silver lining to the “bucket method” it’s that you will truly get to see how harsh of an environment it is inside a water heater and how disgusting it is inside. It will give you something to think about next time you take a shower or wash your vegetables.
To hook everything back up make sure you close your drain valve. Remove the hose, if applicable, and make sure your tub faucet is closed. Open the water supply. Then turn your electricity back on or the gas control knob back to its original location. Go ahead and open the tub faucet again to bleed the pipes of air. It may come sputtering out for a few minutes but give it time and you will be back up and operational in no time!
While you are doing this, assuming you are keeping the water heater, I urge you to flush and clean your water heater while you are at it.