If your shower doors are spotted and your faucets wear a chalky white crust, you already know your water carries a lot of minerals. What you can’t see is the same buildup collecting inside your water heater, where it costs you energy, makes noise, and shortens the life of the tank. A regular water heater flush is one of the simplest ways to fight back.
Below, the plumbers at Public Service Plumbers explain what hard water does to tank and tankless heaters, how to flush yours, and when a water softener or filtration system is worth the investment.
What Makes Water “Hard”?
Hard water contains dissolved minerals, mostly calcium and magnesium. They’re harmless to drink, but they don’t stay dissolved when water heats up. Heat causes them to settle out as scale and sediment.
How hard your water is depends on your city and its water source. You can find your hardness level in your city’s annual water quality report, often called a Consumer Confidence Report.
What Hard Water Does to a Tank Water Heater
Every time a tank water heater warms a fresh batch of water, a little more mineral sediment sinks to the bottom. Over months and years, that layer grows. Here’s what it causes:
- Popping or rumbling noises. In a gas heater, water trapped under the sediment boils and bursts through it. That sound means the burner is working harder than it should.
- Higher energy bills. Sediment acts like insulation between the burner and the water, so the heater runs longer to reach temperature.
- Less hot water. Sediment takes up space in the tank, and showers seem to run cold sooner.
- Burned-out elements. In an electric heater, the lower heating element can get buried in scale and fail early.
- A shorter tank life. Extra heat at the bottom of the tank stresses the steel and its lining, which can lead to leaks.
What Hard Water Does to a Tankless Water Heater
Tankless heaters don’t collect sediment in a tank, but scale builds up inside the heat exchanger instead. That can lead to lower flow, temperature swings, error codes, and reduced efficiency. Most manufacturers recommend descaling on a regular schedule, and homes with hard water may need it more often. If your tankless unit is showing these signs, our tankless water heater repair team can descale it and check for other problems.
How Often Should You Flush Your Water Heater?
Many manufacturers recommend a water heater flush at least once a year. In homes with hard water, every six to twelve months is a sensible target. Fall is a good time, before winter showers and holiday guests put the heater to work.
How to Flush a Tank Water Heater
Always check your owner’s manual first. The basic process looks like this:
- Turn off the heat source. For a gas heater, set the control to “pilot” or “vacation.” For an electric heater, switch off the breaker.
- Let the water cool. Water in the tank can scald. Waiting a few hours is safest.
- Shut off the cold water supply at the top of the heater.
- Attach a garden hose to the drain valve near the bottom, and run it to a floor drain or outside.
- Open a hot water faucet inside the house to let air in, then open the drain valve.
- Flush out the sediment. Once the tank drains, briefly open the cold supply to stir up what’s left, and repeat until the water runs clear.
- Close the drain valve and refill. Let the tank fill completely, and wait until water flows steadily from the open hot faucet before restoring power or gas. Turning on an electric heater with an empty tank can burn out the elements.
If your water heater hasn’t been flushed in years, call a plumber instead. Old plastic drain valves can crack or refuse to close, and heavy sediment can clog the valve partway through.
Signs It’s Time for Repair or Replacement
A flush helps, but it can’t undo years of damage. Call for water heater repair if you notice:
- Rusty or discolored hot water
- Water pooling around the base of the tank
- Loud banging that continues after a flush
- Hot water that runs out much faster than it used to
- A tank that is more than 10 years old
If replacement makes more sense, we install gas, electric, hybrid electric, and tankless water heaters, and we’ll help you choose the right fit for your household.
When Is a Water Softener Worth It?
A softener removes calcium and magnesium before water reaches your heater, fixtures, and appliances. It’s worth a serious look if:
- You flush your heater and still find heavy sediment each time
- You have a tankless water heater and want to cut down on descaling
- Scale keeps building up on faucets, showerheads, and glass
- You’ve replaced a water heater or dishwasher sooner than expected
- You’re investing in a new water heater and want to protect it
You have options beyond a traditional salt-based softener. Salt-free conditioners change how minerals behave so they’re less likely to form scale, though they don’t remove the minerals. Whole-home filtration can address taste, odor, and chlorine. Our team can walk you through the options and recommend the right water filtration system for your home.
One note: if you add a softener, have the heater’s anode rod checked on a regular schedule. Softened water can wear anode rods faster.
Hard water affects more than your water heater. Mineral buildup inside drain lines can slow them down too, which our pipe descaling services can clear.
Schedule a Water Heater Flush With Public Service Plumbers
Public Service Plumbers has served Dallas homeowners since 1959. Whether you need a water heater flush, a tankless descaling, or advice on a softener, our licensed plumbers serve Dallas, Plano, Richardson, Garland, Highland Park, and surrounding communities.
Call (214) 612-7292 or request service online. Check our current specials for water heater and filtration savings, and ask about our Shield of Protection membership.
License: M-2250
