A word of advice: If you haven't flushed your water heater in several years, you may be better off getting a licensed plumber to do the job. You run the risk of activating potential leaks. You see, it's quite possible the sediment that has been there for years has produced cracks in the bottom of the tank.
Most people call in a plumber to flush the water heater, but you can do it yourself if you are up to the task.
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.
If you flush a water heater that already has a significant sediment buildup, it can actually cause more problems. Excessive or large sediment pieces can get stuck in the tank drain valve, or end up exiting the water heater and going through the pipes in your home – and neither of those is an easy fix.
Over time, sediment builds up in the bottom of a water heater, which can lead to clogs, says The Family Handyman. Draining a water heater helps flush out this sediment, usually made up of minerals and other debris, that may cause it to malfunction, says the DIY Network.
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.
The difference between draining and flushing your water heater lies in the status of your water supply. If you shut your water supply off, you're simply draining your water heater. If you leave the water supply on, then you're flushing it out.
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. However, larger tanks (80 gallons or more) found in homes with larger families can take longer, usually from 30 to 60 minutes; sometimes more.
Flush your water heater every six months or so. If you have harder water, or water that contains more minerals, you may want to flush it more often. If you leave town, change your water heater to its vacation setting.
Open a hot water faucet somewhere in the house. Open the water heater drain valve (beware of hot water!). Flush 3 to 4 gallons, then close the valve (if draining, continue until empty).
A water heater flush is exactly what it sounds like. During a water heater flush, your tank is emptied through a hose into an approved drain source. Then the tank is flushed of any sediment or mineral buildup that may reduce the heating efficiency of your water heater or lead to plumbing damage.
If your tank water heater is more than 10 years old, it may be time to consider replacing it. With proper maintenance, a tank water heater tank should last six to 12 years. A tankless water heater can last for more than 20 years. Check your water heater's warranty for the most accurate timelines.
Open a hot water faucet somewhere else in the house and let it run full blast for about 10 minutes to reduce the water temperature in the tank. Shut off the cold water valve at the top of the tank and attach a garden hose to the existing drain valve and route it to a floor drain.
Typically, draining a 40-gallon water heater takes somewhere between 30 and 45 minutes. The overall time is heavily influenced by the size of the unit and the rate at which the water can exit the tank through the drain valve.
Flush the tank regularly
This can shorten the lifespan of the unit and lead to expensive repairs. To avoid this, it's important to flush the tank regularly. Most manufacturers recommend flushing the tank once a year. But if your home has hard water, you probably need to flush it more often.
If your water heater is old, it's possible that the anode rod inside of it is corroded. When this happens, the corrosion can break off and enter your home's water supply, causing black specks to appear in your water.
If your hot water runs out too fast, you may have an issue with: Too much hot water demand from multiple sources at the same time. Sediment build up inside of your water heater tank. A broken dip tube.
Typically, the rule-of-thumb is that you want a 40 gallon tank for 1 to 4 people, a 50 gallon tank for 4 to 6 people, and a 50 gallon high recovery or 75 gallon tank for 6 to 8 people.