How Do I Flush my Water Heater?

How Do I Flush my Water Heater

Water heater maintenance and flushing a water heater aren’t things the typical homeowner spends much time considering. However, without periodic routine maintenance, you may find yourself experiencing a gradual but annoying shortening of your available hot water supply. A poorly maintained heater uses more energy with less return. You’ll see that in your monthly energy bill. Water heaters are pricey. Periodic water heater maintenance goes a long way toward keeping its performance at peak throughout the full warranty period and beyond. 

What Gets Flushed From My Water Heater?

Natural minerals in your water supply, typically magnesium and calcium, fall out of solution when heated and build up at the bottom of your water heater. If you’ve got a soft water plumbing system, your heater may not build up sediment as quickly, but you will need to check the heater anode at least once a year. Soft water corrodes anodes much faster because of the salt that replaces the hard water elements. Without soft water treatment, you will only need to check the anode every six years. 

And about that anode: it’s there to prevent water tank corrosion that would occur on the inside. Without it, the tank could rapidly develop a significant leak at the bottom and require a complete replacement. Tank corrosion and corrosion from old water supply lines also contribute to the sediment that settles to the bottom of your hot water tank.

Why It’s a Good Idea to Call Benjamin Franklin Plumbing 

While there are several maintenance operations that you can perform yourself, we recommend calling us to inspect and maintain a hot water heater.

  • Water heaters are high-pressure installations that combine gas, electric, heat, and water. They must be approached with caution and know-how. 
  • A Benjamin Franklin Plumbing technician will not only flush your water heater but also perform a multi-point inspection of the entire unit and show you how to get the most efficiency and longevity out of your heater.
  • Many times, a decline in hot water supply is due to more than just the need for a flush. Having Benjamin Franklin Plumbing on-site saves you repeat visits. Everything necessary to bringing your heater up to speed gets done in one visit.
  • If your heater can give you more years of service, we will tell you. If it needs to be replaced, we’ll show you why. We will also show you many choices for a new heater that is perfect for your home and living conditions – all at discount prices. 

Flushing Your Hot Water Heater

A periodic flush ensures the sediment build-up doesn’t calcify and become impossible to remove. How often to flush? That depends on how hard your water is. A flush every six months is about average, but if your water supply has a very high mineral content, flush every other month.

  • Check your heater’s operating manual before you do anything else. Directions are often also posted on the side of the tank. Familiarize yourself with the components of the heater before you begin. Wear protective gloves and safety glasses, as you will be dealing with hot water and metal parts. If you have no instructions, find the manual for your specific model online.
  • Turn off the gas to the heater per your heater’s instructions. You may be able to turn the setting knob to “pilot” or a vacation setting. If your heater is electric, turn it off at the circuit breaker panel.
  • Turn off the cold water supply to your heater. This is typically found at the top of the tank. 
  • Turn on at least one hot water faucet. The more faucets you turn on, the faster the tank should drain. Keep these turned on throughout the flushing process.
  • Put a bucket under the drainage pipe connected to your pressure relief valve and open the valve. The water coming out will be hot, so be very careful. This will help the flow of the flush. If nothing happens when you open the valve, it must be replaced. You are far better off calling us to flush your hot water heater, as the process performed incorrectly is very dangerous.
  • Connect a hose to the drainage spigot at the bottom of the tank. Make sure the hose is long enough to carry the rusty water to a safe place well beyond the foundation walls and away from plants and pathways. 
  • Turn on the spigot and let the water drain until it is clear. 
  • If you have a lot of sediment, the water might not run clear before the tank is empty. In that case, turn on the cold water spigot that leads into the tank and let it run until the water from the hose is clear. 
  • Turn off the drainage spigot and remove the hose. 
  • Close any faucets you had running and close the pressure relief valve.
  • Turn on the cold water spigot to your heater. 
  • When the tank is full, let off the excess air by opening the pressure relief valve. Alternatively, you can leave the hot water faucets open until clear water starts coming out. The idea is to get trapped air out of the system.
  • Turn the gas dial back to its standard operating setting. If electric, turn the circuit breaker back on.
  • Write the date of the flush and the date of the next scheduled flush so you can keep track of timing. 

What About a Tankless Water Heater?

Tankless heaters can also accumulate sediment from the water supply but require a different approach to flush. Most manufacturers recommend an annual flush if your mineral content is moderate and twice as often if your water is very hard.

Flushing the tankless heater requires some electrical knowledge and access to a portable pump. Benjamin Franklin Plumbing provides this service and can flush your tank quickly and professionally. If you feel up to it, you can take the DIY approach and buy a tankless water heater flush kit at a hardware store at about $200.