Salt Lake hard water vs. your water heater

HVAC tips for Utah homes

Much of the water in the Salt Lake Valley is hard. That means it carries a lot of dissolved calcium and magnesium. You see it as white spots on glasses and crust on faucets. Inside your water heater, the same minerals are building up where you can't see them.

Heat makes the problem worse. When water is heated, more of those minerals drop out as scale. So the water heater is where hard water does the most damage in most homes.

What happens inside a tank water heater

In a tank heater, minerals settle to the bottom as sediment. Over months and years, that layer gets thicker. It causes a few problems:

• Noise. Water gets trapped under the sediment and boils in small bursts. You hear popping, rumbling or crackling when the burner or element runs.
• Wasted energy. On a gas heater, the burner has to heat through the sediment layer to reach the water. It runs longer to do the same job.
• Less hot water. Sediment takes up space in the tank.
• Overheated tank bottoms. The steel under the sediment runs hotter than it should, which can shorten the tank's life.
• Failed elements. On electric heaters, the lower element can get buried in scale and burn out.

Flushing a tank water heater

Most manufacturers recommend draining and flushing a tank heater about once a year. With valley water, it's worth sticking to that. The basic steps:

1. Turn off the heat source. On a gas heater, set the control to "Pilot" or "Vacation." On an electric heater, turn off the breaker.
2. Shut off the cold water supply at the valve on top of the heater.
3. Connect a garden hose to the drain valve near the bottom. Run it to a floor drain or outside, somewhere hot water won't hurt anything or anyone.
4. Open a hot water faucet in the house so air can get in and the tank can drain.
5. Open the drain valve and let the tank empty. The water will be hot.
6. Flush. With the drain still open, turn the cold supply on for short bursts to stir up and rinse out sediment. Repeat until the water runs clear.
7. Refill before turning the heat back on. Close the drain, open the cold supply, and wait until the open hot faucet runs steady water with no sputtering. Then turn the gas or breaker back on.

Turning on an electric heater before it's full can burn out the elements in seconds. Don't skip that last step.

A word of caution on older heaters. If the tank has never been flushed, the drain valve may clog with sediment or fail to close fully once opened. Plastic drain valves are especially prone to this. If your heater is older and you've never flushed it, it may be better to have us do the first one.

The anode rod

Every steel tank has an anode rod, a metal rod that hangs inside the tank. It corrodes on purpose, so the tank doesn't. Once the rod is used up, the tank starts to rust from the inside.

Checking the anode every few years and replacing it when it's worn down is one of the best ways to get more life out of a tank. It takes the right socket, some muscle and sometimes a flexible rod if there isn't much ceiling room. If you have a water softener, the anode can wear faster, so check it more often.

If your hot water smells like rotten eggs, the anode rod may be reacting with something in the water. A different rod material often fixes it.

Tankless water heaters and scale

Tankless heaters don't collect sediment the same way, but they're more sensitive to scale. Water passes through a narrow heat exchanger, and minerals coat the inside of it. As scale builds up, the heater loses efficiency and may start throwing error codes or shutting down.

The fix is descaling. Most tankless units have service valves for this. A small pump circulates a descaling solution or white vinegar through the heat exchanger for a period of time, then the unit is flushed with clean water. Many manufacturers call for this annually, and hard water is exactly why. Some units also have an inlet screen that should be cleaned at the same time. Check your owner's manual for the exact steps and interval.

See our tankless water heater services for more.

Does a water softener help?

A softener removes most of the hardness minerals before they reach the heater. That means much less sediment and scale. It doesn't mean zero maintenance. You still want to flush a tank and check the anode, and a tankless unit still benefits from periodic descaling. Some tankless manufacturers also offer scale-prevention filters for the inlet line.

Signs your water heater needs attention

• Popping or rumbling that's getting louder
• Hot water runs out faster than it used to
• Rusty or discolored hot water
• Rotten-egg smell from hot water only
• Water dripping from the temperature and pressure relief valve or its pipe
• Moisture, rust or a puddle at the base of the tank
• Error codes or shutdowns on a tankless unit

When to call a pro

Call if you see water at the base of the tank. A leaking tank can't be patched, and it can fail without much warning. Call if the relief valve is discharging, since that points to too much pressure or temperature. Call if you smell gas near the heater, after you're safely outside. And call if you'd rather not flush an old tank or pull an anode yourself.

Our water heater repair page covers what we fix. If your tank is getting on in years and the problems are stacking up, the repair-or-replace tool can help you decide, and water heater installation covers new tank and tankless options. Add flushing and descaling to your yearly maintenance checklist so it doesn't slip.