How To Remove Sediment From A Water Heater


If you’ve been experiencing trouble with your water heater, chances are you’ve been Googling the issues only to find yourself here. Sediment buildup is a common issue with water heaters that can result in multiple issues, including taking a long time for water to heat up, fluctuating temperatures, or no hot water at all. Removing sediment from your water heater is a fairly simple fix that we will go over in this article.

What Is Sediment Buildup?

Sediment buildup is something that happens in all storage tank-style water heaters. During the heating process, minerals like calcium and magnesium form into solid sediments and settle into the bottom of the tank. A large buildup of sediment buildup begins to cause many problems that will worsen over time if not taken care of promptly.

How Do I Know I Have Sediment Buildup?

As mentioned above sediment buildup can cause a fluctuation in water temperatures from too hot to lukewarm. A diminished supply of hot water with a rise in energy or a rumbling or popping sound when the water heater is running, can signal the accumulation of sediments.

Is Sediment Buildup Dangerous?

No, Sediment build up is not dangerous, but it can cause many issues. Sediment impacts your water heaters' ability to maintain consistent water temperature and efficiency. Severe buildup can cause clogs in the drain valves, blockages in the water lines, and even cause tank failure if left untreated.

Can Sediment Buildup Be Avoided?

Unfortunately, sediment buildup cannot be avoided completely but we can prevent these problems by periodically flushing out your water heater twice a year. You can always hire a plumber to do the job for you, or you can follow this guide to do it yourself and save money.

Even if you decide to drain the water heater yourself you should still have your water heater serviced annually to prolong the life of your unit.

What You’ll Need

First, gather your supplies. It’s always easier to gather everything you need before you get started so you aren’t running around trying to find things in a panic because you loosened a vale and have water running everywhere with nothing to put it in, trust me on this one. Things you will need are:

  • Garden Hose
  • Bucket
  • Towles
  • Chanel Locks
  • This Guide

Power Source

Water heaters use some form of power like gas or electricity and before messing with any part of your water heater you need to turn off the power to the heater to avoid electrocution. It’s always a good idea to turn your water heater off the night before so the water in the tank can cool. This not only eliminates the risk of burning yourself but can also allow you to use the water elsewhere instead of just draining it off in the grass or sewers.

If you have an electric water heater you will have to locate the breaker box, and the fuse assigned to the water heater. If you don’t know which switch belongs to the water heater you will either have to cut the main switch and work with work lamps.

If you have a gas water heater, you will need to find the thermostat on the outside of the water heater. Most of the time the thermostat has a red knob located near the pipe that enters the unit. You should make a mental note or write down the temperature setting your water heater is set to so you can return it to the same temperature later on. Turn the thermostat to the lowest setting, most of the time this is marked as “pilot” this will ensure that the water is not heated as it goes into the tank.

Turn Off The Water Supply

Once you’ve turned off the heating element, water is no longer heated as it pours into the tank. If you forgot to turn off your water heater the night before or you only have one day to do this project you can always turn on a nearby faucet like a sink or tub and allow the hot water to drain out of the tank naturally and it will refill with cold water.

This isn’t necessary but it is important to avoid getting burned. Water in a water heater can get as hot as 140℉ but it is recommended to keep the temperature set around 120℉, either of these temperatures can burn you in large quantities and even scald unprotected skin.

After the water in the sink or tub begins to run lukewarm, or if you turned off the heater the night before you can skip running the water into the tub. You will need to locate the water supply valve and turn it off. This valve is generally located where the cold water pipe enters the top of the tank. If you are unsure of its location a quick search of the make and model of your water heater should be able to easily guide you to the valve.

Preparing To Drain The Water Heater

Before you drain your water heater, you need to give the water a place to go. Water heaters most commonly hold 40 or 50 gallons of water but some can hold up to 80 or more. It’s important to get an idea of how much water will be draining out of your water heater so you can have an adequate place to drain the water.

You can either drain it out directly into your garden, fill up several Rubbermaid totes to use the water for plants or other needs as you see fit, or you can always just drain it off into the driveway or yard.

Locate the drain valve located at the bottom of the water heater. Most of the time these valves are made of plastic but can also be made of metal and strongly resemble an outdoor faucet.

Connect your garden hose to the drain valve with a pair of channel locks to ensure it doesn’t leak or pop off while you’re draining the tank. Finally stretch out your hose to the location you’ve chosen to let the water drain off to. You should also open up a nearby faucet to prevent a vacuum from being created in the tank, this will also allow most of the water to drain out of the tank.

If you’ve decided to attempt this with hot water, be sure to wrap a towel around the valve to ensure you dont get burnt with any excess water. Also, remember that this water can burn grass or scald children or pets if they are in the area while you’re working.

Draining The Water

Open the drain valve to start draining the water heater. You can also open the pressure relief valve located at the top of the tank to improve the water flow coming out of the drain. Be careful when straining the drain because it may be several years old and could break causing a powerful spray of water.

If you think your valve is faulty it is best to put this on hold until you can call a professional who can properly handle a valve replacement. This is also something you could do yourself if you feel up to the task, but remember if you rent your home or your water heater you may be required to call in a professional so always check your rental agreements.

If you did not allow the water to cool and are attempting to do this with hot water any steam or vapors coming off of the water can sometimes cause steam burns which are more dangerous than scald burns. Use extreme caution and wear proper gloves and face shields and ensure no pets or children are around your work area.

Testing For Sediment

After about 20 minutes of draining grill up a small bucket with water and let it set for about 60 seconds without disturbing the water inside. If the water is cloudy or has sediment in the bottom of the bucket let your tank drain for about 10 more minutes and test again. Once the water is clean and no sediment is present you can continue to the next step.

Finishing Up

It’s finally time to close the drain valve and remove the garden hose. Make sure to walk the water out from the hose starting at the water hose. You can achieve this by holding the hose above your head as long as the water isn't hot and walking under the hose to the end where you have the water draining. Leave the faucet you had open while draining the tank open as this will help get the air out of the lines when you turn the water back on as well.

Open the water lines back up and let the tank begin to fill with water. As the tank begins to fill back up air will be forced out of the tank and out of the open faucet, you will notice spurts of air and low water pressure until the tank fills back up. Don’t turn the heater back on until full pressure has returned and air has stopped coming out of the lines. Remember to set the thermostat back to its original temperature.

Once power has been restored, turn off the faucet and close the pressure relief valve. You should wait for about 30 minutes and test the temperature with the nearest faucet.

You’ve successfully flushed all the sediment out of your water heater and restored it to proper working order!


Sediment buildup is normal and there isn’t a way to prevent it from happening. Biannual maitenence on your water heater can prevent any major problem due to sediment from arising but any work you do on your water heater should be done with extreme caution because of the risks of burning yourself or others with the hot temperatures a water heater can produce.