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How Often Should I Flush My Water Heater?

Your hot water heater tank—it’s one of the things that many people don’t think about until it doesn’t work. When it’s installed well and set to the right temperature and pressure settings, you don’t have to do much to keep it running efficiently. However, like other major equipment in your home, it needs your attention occasionally. Follow these routine maintenance tips to ensure that your water heater is in top shape.

How Often Should You Flush a Water Heater Tank?

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The frequency with which to flush a water heater depends on the size of the tank and the amount of hot water used. It is as good idea to refer to the manufacturer’s instructions. Usually, the more hot water a household uses, the greater the maintenance flushing frequency.

With time, water heater sludge accumulates at the bottom of a tank as minerals, sediment and other deposits settle in the water. Flushing out these deposits prolongs the heater’s life and prevents malfunctions, such as cold bursts of water.

If you don’t have access to the manufacturer’s instructions, the following serves as a general guide:

  • One or two people in a home: Inspect the water heater every six months and drain it every 12 months
  • Three to five people in a home: Inspect the water heater every four months and drain it every eight months
  • Six or more people in a home: Inspect the water heater every four months and drain it every six months

You may need to drain the hot water tank more often if your water comes from a well or if your municipal water has abnormally high sediment content.

Additional Water Heater Maintenance Tasks

When you flush a hot water heater tank, it is a good time to perform extra maintenance tasks that will help prolong the unit’s life and ensure its efficiency:

  • Water pressure: Hot water heaters have pressure gauges by the hose bib or drain valve. During the day, the water pressure should be at or below 60 psi, or pounds per square inch. At night, it should be at or below 80 psi. If the water pressure is above these values, install a pressure reducing valve (PRV) to prevent safety hazards.
  • Pressure reducing valve: A good setting for a pressure reducing valve is between 50 and 60 psi. Anything higher could damage the water heater, dishwasher, washing machine, toilet valves or the refrigerator’s icemaker. If you see water dripping from the pressure reducing valve, this is a sign that the water pressure is too high.
  • Expansion tank: Expansion tanks that accompany hot water tanks on closed plumbing systems control thermal expansion. The tank’s air pressure should match the water pressure.
  • Temperature and pressure relief valve: Found toward the top of a hot water tank, the temperature and pressure relief valve (T & P valve) opens if a tank becomes over-pressurized. When it opens, it releases air. If it doesn’t work correctly, a tank may over-pressurize and explode. If you notice water dripping from the valve, this is a sign that the water pressure is too high. If the water tank doesn’t have an expansion tank and the pressure is high, it is a good idea to install one.
  • Test the T & P valve: After turning off the power or gas to the water heater and the cold-water inlet, open the valve by pulling the trip lever up. You will hear air hiss from it. Water or vapor might also exit from it, so it’s a good idea to have a bucket handy. If you don’t hear air exiting the valve, replace the valve after you drain the water heater tank.
  • Anode rod: Anode rods in hot water tanks reduce and prevent corrosion, extending the life of the water heater. After turning off the gas or power to the water heater, turn off the cold-water supply and relieve the pressure inside the tank by opening a nearby hot water tap. Then use a socket and impact wrench to remove the anode rod, which is toward the top of the tank, near the cold-water inlet. The rod might have a cap over it. It is okay if the metal rod has a bit of pitting or corrosion. You will need to replace it, however, if it’s missing, missing portions of the surface or does not have a smooth surface. Another sign that you need to replace the anode rod is seeing milky water when you flush the tank. After replacing the rod in the tank, turn on the cold-water supply so water fills the tank before turning power to the water heater back on.

Give your water heater the attention it deserves to prolong its life and save energy. When you encounter a problem that you can’t repair on your own, hear unusual noises from the tank or simply want an expert to perform maintenance services for you, get in touch with AAA Heating & Cooling to schedule an appointment.