Protect Your Water Heater From Corrosion

Written by Angie's List Staff
Updated June 15, 2021
Water heater and furnace
Protect your investment in your water heater by keeping it from hard water. (Photo by Summer Galyan)

Calcium build-ups from hard water can lead to annoying water spots and soap scum.

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Flushing your water heater, maintaining the anode rod, installing a water softener and regular inspections can add years to the life of a gas or electric water heater. Household tap water that has a high mineral content — also known as hard water — can be a nuisance to your plumbing system. Hard water can leave water spots on dishes, can make hair look dull and feel sticky and can lead to filmy soap scum on the surfaces of your showers and tubs, sinks, faucets, etc.

Calcium build-up from hard water can go beyond being a nuisance and shorten the lifespans of water-using appliances like your washing machine, dishwasher and your water heater.

Most water heaters are designed to help ward off corrosion using anode rods, according to the Plumbing Tips blog from McCoy Plumbing, a highly-rated plumbing service in Charlotte. These metal anode rods — also known as sacrificial anode rods — are designed to draw the deterioration to themselves, which keeps the damage from spreading to the tank lining of the water heater.  As the adjective “sacrificial” indicates, the strength and integrity of the anode rods are compromised as a means to preserve the lining of the water heater tank.

This is a great line of defense, so long as the anode rods last. But homeowners should know that depending on your water quality, the rods may corrode more quickly than expected. You can tell an anode rod has gone bad if it looks as if it’s been eaten away and it has become flexible.

Rods that have gone bad put your water heater at risk, as the minerals will then begin to attack the lining of the tank walls, says Craig Foster of Dallas plumbing company Baker Brothers Plumbing.

So what can a homeowner do to preserve a water heater?

In order to protect hot water heaters, homeowners should have their water heaters flushed and maintenanced every year or so, Foster says. This will help extend the life of the water heater. Homeowners budgeting time and money for home upgrades should, however, be aware that water heaters don’t last forever and will still have to be replaced eventually, even if they’ve been well cared for.

Fight hard water with a water softener; see how they work with this Hard Facts of Water Softeners infographic.

Has hard water ever damaged your appliances? Tell us about it in the comments below.

Editor's note: This is an updated version of an article originally published on Aug. 29, 2012. 

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