How to Flush and Clean a Water Heater

Getting sediment and minerals out of your water heater extends its life and helps it run more efficiently. Flushing your water heater is an important maintenance task that you should perform annually.

Flushing removes built-up sediment from the tank that can cause corrosion and restrict water flow. Cleaning the tank also helps remove any bacterial growth that can reduce the efficiency of your heater.

With some simple steps and basic equipment, flushing and cleaning your water heater is a do-it-yourself project. We’ll walk you through the process of draining the tank, flushing it out, inspecting it, and getting your water heater back up and running cleanly.

When to Flush Your Water Heater

You should flush your hot water heater about once a year to keep it operating at peak efficiency. Some signs that it’s time to flush include:

  • Decreased hot water pressure
  • Rumbling or gurgling sounds
  • Discolored water
  • Rotten egg smell from the hot water

Flushing yearly helps remove the sediment that builds up at the bottom of the tank. Letting sediment accumulate can lead to more rapid corrosion and failure over time.

Items Needed for Flushing a Water Heater

Flushing a water heater is a straightforward process that doesn’t require many supplies. Here are the basic items you’ll need:

  • Garden hose – at least 10 feet long
  • Bucket – at least 5 gallons capacity
  • Adjustable wrench
  • Phillips and flathead screwdrivers
  • Teflon tape
  • Replacement heating elements (if needed)
  • Funnel
  • Rag or towel

Optional items that can help are:

  • Water heater flushing kit with hoses and fittings
  • Wet/dry vacuum to suck out sediment
  • Work gloves to protect hands

Make sure you locate the water shutoff valve for the heater and know how to turn off the gas or electricity supply before getting started.

How to Flush a Gas Water Heater

Gas water heaters have some additional steps for the flushing process since you need to turn off the gas and disconnect the pilot light. Follow these instructions to flush a gas heater:

Turn Off Water and Gas Supply

Locate the cold water shutoff valve that supplies the heater and turn it clockwise to shut off the water.

Then find the gas supply line shutoff valve and turn it clockwise to close off the gas.

Drain the Tank

There should be a drain valve near the bottom of the tank. Place a bucket underneath and open the drain valve to allow the water to empty out of the tank completely.

Expect sediment to come out at first, which will slow to a trickle as the tank drains. This process can take 10-15 minutes.

Disconnect Gas Line and Pilot

Use an adjustable wrench to disconnect the gas supply line from the gas control valve on top of the tank.

Unscrew and remove the outer cover on the gas control valve/thermostat. You’ll see a small copper pilot tube going to the pilot light – this needs detached next.

Gently bend the copper pilot tube to loosen it and pull it off the pilot light assembly.

Flush Tank and Remove Heating Elements

Attach a garden hose to the drain valve and turn on the water to full pressure to flush the interior of the tank.

Let the water run for 3-5 minutes to wash away all sediment. You’ll see sediment exiting through the open top.

Remove and inspect the heating elements while flushing. Use a screwdriver to detach and pull them out. Look for scale buildup or corrosion and replace if needed.

Reassemble and Refill

Once flushing is complete, replace the heating elements and reattach the gas line and pilot tube. Make sure new Teflon tape is used on any threaded connections.

Close the drain valve and open the cold water shutoff to refill the tank. When water starts flowing from the hot water side, open the gas valve to restart the pilot light.

Inspect for any leaks at fittings and valves before relighting the pilot. Then turn on a hot water faucet and let the tank completely refill and reheat.

Flush out any discolored water until it runs clear. Your gas water heater is now flushed and ready to safely operate.

How to Flush an Electric Water Heater

Flushing an electric water heater is simpler than a gas heater since there is no pilot assembly to disconnect. Follow these steps:

Turn Off Power and Water

Start by flipping the circuit breaker off for the electric water heater to cut power to the heating elements.

Shut off the cold water supply valve located on the incoming pipe to the water heater.

Drain Tank

Place a bucket or pan under the drain valve, then open the valve. Gravity will drain the water out of the tank.

Tank draining can take 10-15 minutes. Sediment will probably come out at first, then clear once most water has exited.

Remove Heating Elements

While the tank drains, use a screwdriver to detach the electric heating elements from the screw flanges.

Carefully pull the elements out, inspect for any corrosion, and replace if needed. Scale buildup reduces efficiency.

Attach Hose and Flush

Once drained, close the drain valve. Attach a garden hose to the drain valve opening.

Turn on full water pressure to flush the tank interior. Let water run 3-5 minutes to wash out all sediment.

Reassemble and Refill

Replace the heating elements if removed. Make sure new Teflon tape is used on their threads.

Close the drain valve and open the cold water shutoff to refill the tank. When water flows from the hot side, turn power back on.

Inspect for leaks at heating element flanges or valves before leaving. Turn on a hot water tap until clear water runs to complete the flush.

Flushing Tips

  • Cooler water flushes out sediment faster than hot. But you need to run hot water last to purge any discoloration.
  • Use a wet/dry shop vacuum to suck out loose sediment through the drain valve or heating element openings.
  • Inspect the anode rod while flushing and replace if over 50% corroded. It protects against corrosion.
  • Don’t drain water onto the electrical elements, thermostats, or burner. Keep connections dry.
  • If your water heater has sediment issues, install an in-line filter on the cold water supply.
  • For frequent sediment, increase flush frequency, check supply valves, or test water hardness.
  • Be sure to reattach the pressure relief valve discharge pipe after flushing.
  • Check that all fittings are tight and leak-free before leaving the water heater.

Signs of Water Heater Problems

While flushing your heater, inspect the interior and exterior for any signs of issues:

Rust Colored Water

Red, brown, or rusty colored water usually means corroded pipes or a rusted interior tank. Flushing can clear it up temporarily but a new heater may be needed.

Rotten Eggs Smell

An odor like rotten eggs is caused by sulfur bacteria. Flushing helps eliminate bacteria but a persistent smell means a full sanitization is required.


Check around the base, pipes, and valves for any weeping water that indicates a leak. Tighten fittings or drain the tank and inspect if leaks are found.


Loud rumbling noises during heating indicate mineral sediment buildup in the tank. Flushing helps remove the sediment causing the noise.

Low Water Pressure

Decreased flow at taps alongside rusty water indicates mineral scale restricting pipes and valves. Flushing is needed to remove the scale buildup.

How to Sanitize a Water Heater

For bacteria growth indicated by foul eggs smells, you’ll need to sanitize the tank after flushing. Sanitizing kills bacteria and further improves water quality.

Follow these steps to sanitize with household bleach – check the tank coating first to ensure bleach can be used.

Drain and Flush

Start by fully draining and flushing the water heater as outlined previously. Get out as much sediment as possible.

Calculate Bleach

Determine the tank capacity either from the manual or measuring height and diameter. Allow 1 cup bleach per 40 gallons capacity.

For a 50 gallon tank, that would be 50/40 = 1 1/4 cup bleach.

Add Bleach and Fill

Mix the bleach amount in a bucket first. Turn off the cold supply and pour the diluted bleach into the tank through the drain valve.

Refill the tank by turning the cold water back on. Let it fill completely to put the bleach solution into the entire system.

Circulate and Flush

Turn a hot water tap on to circulate the sanitizing bleach for 15-20 minutes, then flush the solution out through the drain valve until empty.


Close the drain and turn on the cold water supply to refill the tank normally. Open hot water taps to purge air until a steady stream flows.

The hot water may have a chlorine taste at first but is safe after flushing thoroughly. Your system is now disinfected!

DIY Water Heater Maintenance

With annual flushing and periodic inspections, your water heater should operate efficiently for years before needing replacement. Here are some key maintenance tips:

  • Inspect anode rods – Check for corrosion every 2-3 years and replace if over 50% worn. Protects tank.
  • Relieve pressure valve – Open the relief valve 4-6 times a year to ensure it isn’t stuck shut.
  • Check breather tube – Clear any dust or obstructions from the pressure relief tube.
  • Replace filters – If using inlet water filters, replace cartridge yearly or as needed.
  • Inspect valves – Maintain supply valves and drain valves to prevent leaks. Replace worn washers.
  • Check pipes – Inspect water connections and pipes for leaks annually. Fix any corroded or weeping fittings.
  • Test T&P valve – Manually test the temperature and pressure relief valve annually by briefly opening it.
  • Check insulation – Ensure insulation blankets or wraps are intact and sealed to improve efficiency.

Proper maintenance keeps your system operating safely and efficiently for maximum savings on your utility bills.

When to Call a Professional

While do-it-yourself flushing and minor repairs can extend the life of your water heater, some issues do require a professional:

  • Leaks from tank cracks or ruptures
  • Faulty gas valves and controls
  • Tank failures within warranty period
  • Major sediment buildup that flushing cannot fix
  • Persistent bacteria and odor issues after sanitizing

A water heater technician can assess, troubleshoot, and service problems that may be beyond DIY abilities or safety.

They have specialized tools, testing instruments, and parts to fully diagnose and fix all water heater types. It’s recommended to call a professional for any major repairs.

Safety Tips for Water Heater Maintenance

Working on a water heater involves electrical, gas, and plumbing hazards. Keep these safety guidelines in mind:

  • Turn off power and water supply before any work.
  • Allow adequate time for a full cool down before draining hot tanks.
  • Use rubber gloves and eye protection when flushing.
  • Keep connections dry and never douse electrics with water.
  • Have two people to assist with heavy tanks.
  • Ensure gas valves are properly closed and leak-free before turning gas back on.
  • Discharge pressure valves outdoors and in a safe direction.
  • Verify all valves, elements and fittings are properly reinstalled after maintenance.

Exercising caution helps ensure your safety and prevents accidental water or electrical damage.

Frequently Asked Questions

How often should you drain a hot water heater?

Draining or flushing a water heater annually removes sediment and extends the life of your heater. Signs it’s time include decreased pressure, rumbling noises, or rusty/discolored water.

How do you maintain a gas water heater?

For gas heaters, key maintenance is flushing sediment, replacing anode rods every 2-3 years, checking the pilot assembly, testing the relief valve, and inspecting supply gas lines. Perform flushing and inspections annually.

What causes a hot water heater to stop working?

Common causes of water heater failure include sediment buildup, corroded tank linings, leaks, bad thermostats or heating elements, rusted pipes, and pilot light issues. Many problems can be fixed, but major leaks or tank failures require replacement.

Can I use vinegar to clean my water heater?

No, vinegar should not be used in place of flushing. It can be too acidic for some water heater tanks and piping. Flushing with water is the recommended method to remove sediment and minerals from your hot water system.

How much does it cost to have a plumber flush a water heater?

Plumbers typically charge $150-$300 to drain, flush, and refill a water heater, depending on local rates and any repairs needed. DIY flushing only costs about $20-$50 for supplies like hoses and replacement parts.


Performing annual water heater flushing improves performance and helps your heater last longer. It’s one of the most important maintenance tasks that you can easily DIY.

Follow the steps we covered to fully flush out sediment, sanitize the tank if needed, and inspect components. Catching any issues early on lets you repair or replace parts before major tank failure occurs.

With simple regular care, your water heater can provide hot water for your home for 10-15 years, saving you money on utility bills and replacement costs. Proper maintenance gives you peace of mind that this essential appliance is operating safely and efficiently.

How to Flush and Clean a Water Heater

Flushing a water heater extends its life and improves efficiency by removing sediment buildup. This should be done annually to keep your hot water system operating properly.

In this article, we’ll cover:

  • When to flush your water heater
  • Supplies needed
  • How to flush a gas water heater
  • How to flush an electric water heater
  • Flushing tips
  • Signs of water heater problems
  • How to sanitize the tank
  • DIY maintenance
  • When to call a professional
  • Safety precautions

Flushing your water heater is straightforward with some simple supplies. Following yearly flushing and maintenance steps can add years of life to your hot water system.

When to Flush Your Water Heater

Sediment and mineral deposits from water naturally collect in the bottom of your heater’s tank over time. It’s recommended to flush your water heater annually to remove this buildup.

Signs it’s time for a flush include:

  • Decreased hot water pressure
  • Gurgling or rumbling noises
  • Rusty colored water
  • Rotten eggs smell

Regular flushing helps maximize efficiency and lifespan by getting rid of sediment before major buildup occurs.

Supplies Needed for Flushing

You don’t need many supplies for a DIY flush. Have these items on hand:

  • Garden hose
  • Bucket
  • Adjustable wrench
  • Screwdrivers
  • Teflon tape
  • Funnel
  • Rags
  • Drain pan
  • Replacement parts

Optional helpful items include a flushing kit, wet/dry shop vac, and work gloves.

Make sure you know how to shut off the gas or power and water supply to the heater before starting.

How to Flush a Gas Water Heater

Follow these steps to flush sediment out of a gas-powered hot water heater:

Turn Off Water and Gas Supply

Locate the shutoff valves and turn them off to isolate the tank. Turn off the gas first before the cold water.

Drain the Tank

Open the drain valve at the bottom of the heater to empty the water in the tank. Place a bucket or pan underneath to catch water. Let it fully drain all the way.

Disconnect Gas Line and Pilot

Use a wrench to detach the gas supply line from the control valve. Unscrew and remove the outer control unit and disconnect the pilot tube.

Flush the Tank

Attach a garden hose to the drain valve and turn on full water pressure to flush out sediment. Let water run for 3-5 minutes.

Reassemble and Refill

Replace any parts removed like heating elements or thermostats. Reattach gas line and pilot tube with Teflon tape. Close drain and refill tank. Check for leaks before relighting pilot.

How to Flush an Electric Water Heater

Flushing an electric heater involves fewer steps. Follow this process:

Turn Off Power and Water

Flip the breaker off for the water heater and turn the cold water shutoff valve to isolate the tank.

Drain the Tank

Place a bucket or pan beneath the drain valve and open it to allow the tank to empty completely. Takes 10-15 minutes usually.

Remove Heating Elements

While draining, detach and remove the electric heating elements. Inspect and replace if needed.

Attach Hose and Flush

With drain valve closed again, connect a garden hose and turn on full water pressure. Flush for 3-5 minutes.

Reassemble and Refill

Replace heating elements if removed. Make sure new Teflon tape is used. Close drain, open water supply, and turn power back on once refilled.

Flushing Tips

  • Use cooler water to flush, hot water last to purge sediment
  • Vacuum out loose sediment through openings
  • Replace anode rod if over 50% corroded
  • Keep electrical connections dry during flushing
  • Install an inline filter on cold water supply if frequent sediment
  • Increase flush frequency if sediment is excessive
  • Check all valves are tight before refilling tank

Signs of Water Heater Problems

Inspect your system during flushing for any of these issues:

Rusty colored water – Corroded tank or pipes need replacing