No—you should always shut off the power and the water supply to the tank. Shutting off the water ensures that your water heater won't continuously refill while you are trying to drain it, which would likely cause a big mess!
Unless you are the only person in the house and do not drain any water out of the system it is best to shut off the hot water heater before shutting off the mains water.
CAUTION: Power must be OFF before draining the hot water tank. The tank will be substantially damaged if there is no water in it and the power is ON. Connect a hose to the drain valve and direct it to a floor drain. Open the drain valve and flush the tank for about five minutes.
If your water heater doesn't have any leaks, you can move to the next step: opening a hot water tap in your house. Doing this prevents a vacuum from forming and makes draining the tank easier. Keep the tap open until you're finished draining the tank.
Opening a hot water faucet will help the water heater drain faster. Some drain valves may be opened with a handle but others require a flat blade screwdriver. Let the water heater drain completely.
Thankfully, a hot water heater does not require a lot of attention, but draining it regularly may help keep it running efficiently.
How Long Does It Take to Drain a 50-Gallon Water Heater? Draining a 50-gallon water heater for larger units usually takes 45 to 60 minutes. However, it's worth noting that these are approximations, and the actual time can vary.
The fastest way to drain your hot water heater is to use a small section of garden hose that has a fitting that connects to your drain valve. It's usually the same one used for the bib. You'll need to direct the water flow from the hose into a floor drain, bucket, or safe outside area.
While draining the tank, keep the pressure relief valve open. This allows air to enter the tank, facilitating a smoother and faster draining process. It also prevents a vacuum from forming inside the tank, keeping the water flowing consistently and preventing potential damage to the tank structure.
It's not always necessary to drain the entire hot water tank. Since sediment and buildup settle on the bottom of the tank, you may drain a few gallons of water at a time until most of the sediment is flushed out. This also prevents homeowners from accidently damaging the hot water heater by turning it on without water.
It is recommended that you flush your water heater at least once per year. Doing so will help to prevent the potential problems that sediment can bring over time. Typically, it takes one to two hours to flush a water heater. The size of your tank will impact the amount of time it takes to drain.
Else, if you have a full water tank, and you need to turn off the water for an issue unrelated to your water heater, then it really doesn't matter if you turn the water heater on or off.
If neither you nor a professional have flushed your water within the last five years, Water Heaters Now recommends not flushing it yourself.
Water Heater – These always have a shut-off valve. If your tank has two valves, find the one which brings in cold water and turn it off slowly.
Before you begin you should switch off the system completely for safety reasons. You should also allow time for the water in the pipes to cool down. It is important that you turn off the water supply to the boiler as this prevents any water from entering the system whilst you are draining it.
For gas water heaters, turn the gas shut-off valve to OFF, both at your unit and at your home's main gas supply. For electric water heaters, turn the power switch on your unit to OFF, and turn the unit circuit breaker to the OFF position. Turn the water supply to your unit clockwise until the valve lever stops.
If you suddenly drain the water heater and remove this sediment, you are likely to end up with a leaking unit.
It only takes about 15 to 30 minutes to completely drain a water heater. A typical 40- to 60-gallon residential tank found in most homes will take no more than 15 minutes.
Your water heater, just like most appliances in your home, requires power to operate. Depending on your water heater, you may require to either shut off your gas or cut off electricity. It is essential to shut off your gas to ensure that the water is cold when you drain it and to reduce any chance of a gas leak.
Open the hot water tank drain valve. Let the water run out the garden hose. This can take 20 to 60 minutes, depending on how big the tank is. Be careful not to damage or break the drain valve when you open and close it.
While today's water heaters are better designed than older models, they still require regular maintenance in order to prolong their lives. With regular inspection, draining, and flushing, you can expect a gas water heater to last anywhere from 8-12 years and an electric water heater to last anywhere from 10-15 years.
Expect a pro to charge you between $75 and $200 to come to your home to flush your water heater, depending on where you live. While this cost deters many homeowners from performing this annual maintenance, it can extend the water heater's lifespan by years, making it worth the additional cost.