Does a Water Softener Wear Out Your Water Heater's Anode Rod Faster? What Daniel Island Homeowners Should Know

Here's a question I get a lot from neighbors on Daniel Island and over in Mount Pleasant right after we put in a water softener: "Is this going to hurt my water heater?" It's a fair thing to ask, and the honest answer is that soft water is mostly good news for your plumbing, with one part of a tank water heater you should keep an eye on.

I'm Christian with Avery & Sons Plumbing + Tankless. Let me explain what's going on inside the tank, in plain terms.

What an anode rod does

Most standard tank water heaters have a metal rod hanging down inside the tank, usually magnesium or aluminum. Its whole job is to corrode so the steel tank doesn't. The water goes after the rod first, and as long as there's rod left, the tank lining is protected. Once the rod is used up, the water starts working on the tank itself, and that's when rust and leaks show up.

Why softened water can use it up sooner

A softener swaps the hardness minerals in your water for a small amount of sodium. That makes the water a little more conductive, which speeds up the reaction that eats the anode rod. On top of that, hard water tends to coat the rod with a crusty scale layer that slows it down, and soft water doesn't. The result is that in a lot of softened homes, the anode rod gets used up faster than it would on untreated water.

Many water heater manufacturers point this out in their manuals and suggest checking the anode more often when a softener is installed. It's not a reason to skip the softener. It just changes the maintenance schedule.

Signs your anode rod may be gone

• Rusty or brownish hot water. If only the hot side looks off, the tank may be starting to rust from the inside.

• A rotten-egg smell from the hot tap. That's often a reaction at the anode rod. Our post on the rotten egg smell from the hot tap explains what causes it and what actually fixes it.

• Popping or rumbling from the tank. That's usually sediment, but it's a good prompt to have the rod and tank looked at together.

• Your tank is past about five years and the rod has never been checked. That alone is reason enough to take a look.

What we recommend for softened homes

If you have a tank water heater and a softener, plan on having the anode rod checked every couple of years instead of waiting for trouble. Pulling it takes a few minutes for a plumber, and a new rod costs far less than a new water heater. Keep the softener set correctly, too. A system that's set to strip out more hardness than your water actually has, or that's using more salt than it needs, isn't doing the tank any favors.

It also helps to flush the tank once a year. Even with soft water, some sediment settles at the bottom, and flushing keeps the heater running efficiently.

What about tankless water heaters?

A tankless unit doesn't have an anode rod at all, so this particular issue doesn't apply. For tankless owners, the softener is pure upside, since scale is the main thing that shortens their life. We cover that in our post on hard water and tankless water heaters.

Easy next step

Avery & Sons Plumbing + Tankless services water softeners, filters, and both tank and tankless water heaters on Daniel Island, in Mount Pleasant, and across East Cooper. If you're not sure when your anode rod was last checked, call (843) 305-5555 or visit averysplumbing.com and we'll take a look while we're there.

Soft water and a long-lasting water heater can absolutely go together, neighbors. It just takes a quick check on that rod every so often.