Water Heater Repair: Sediment and Bad-Smelling Hot Water

johncarljohnson/flickrSediment and foul odors in your hot water may be a sign of problems with the water heater. Fortunately, there are some relatively simple solutions to common water heater problems, many of them DIY. Check out our handy repair guide.

How to Remove Sediment

Flush the water heater tank at least once a year to remove sediment buildup, lengthen the life of your heater and improve energy efficiency. This can help remove particulates in your water. It also helps with chlorination and other remedies explained below, because built-up sediment can protect bacteria from chlorine. Here are the steps to follow:

  • First, turn off the breaker to an electric water heater or turn the gas valve knob to the “pilot” position on a gas heater.

  • Connect a garden hose to the drain at the bottom of the tank, open the valve and flush for about five minutes.

  • Then shut off the cold water intake and open the hot water faucets to let air in the line and fully drain the system. For further flushing instructions regarding your specific model, check your owners’ manual or manufacturer’s website.

  • Drain the other end of the hose onto a light-colored patio or other area that won’t be damaged by the hot water, but will allow you to see the water draining.

  • If you keep seeing sediment until the tank is empty, you may want to fill and drain the tank again.

  • Hire a reliable, licensed plumber if you're not comfortable taking on this water heater maintenance task yourself.

How to Treat Foul-Smelling Hot Water

Foul-smelling hot water may be caused by bacteria buildup in water heaters. There are three possible solutions to this problem: 

  1. Replace a degraded anode. Water heaters are lined with corrosion-resistant glass, but tiny cracks and holes in the glass can still rust. To prevent rust, anode tubes (typically made of magnesium) in the tank shed electrons that fill the tiny holes. However, excessive electrons can also “feed” the bacteria and generate stinky hydrogen sulfide gas. If the anode tube looks degraded, replace it. Consider replacing the manufacturer’s magnesium anode with a zinc anode, which may work better.

  2. Boil away bacteria. You can save energy by lowering the water temperature in your heater most of the time. However, raising the temperature to 160 degrees for a few hours and flushing the system will kill most bacteria. Before trying this, make sure your heater has a pressure release valve. Also check the owners’ manual or the manufacturer’s website to confirm that this solution is recommended for your system. Finally, keep children away from this potentially scalding, overheated water.

  3. Chlorinate the system. To combat a severe problem, you can try to use a chlorine feeder to maintain a steady one milligram per liter in the hot water system, which will inhibit bacteria growth. The more typical option, though, is to periodically disinfect and flush the hot water heater with a chlorine solution. 

Other Water Solutions

If your hot and cold water both have sediment or foul odors and smells, it is probably not due to a water heater problem. Here are a few other possible remedies:

• Metallic-tasting water, brown sediment in standing water, or brown stains in tubs and toilets may be caused by dissolved iron in the water. To solve the aesthetic problem, install a polyphosphate feeder in the cold-water line going into the water heater. This device wraps harmless polyphosphates around iron particles, keeping them from causing stains. For the taste problem, look for a high-capacity water softener designated to remove iron.

• If you have rust or black specks floating in the water, you may have oxidized iron and manganese compounds. Use a cartridge filter either on your tap or under the sink.

• Other foul odors or tastes in water may be caused by various pollutants in the water. You might want to install an activated carbon filter.

Steve Graham writes for networx.com.

Updated March 6, 2018.

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