Corrosion: the gradual destruction of metal due to a chemical or electro-chemical reaction to the environment. Or, to look at a case you’re probably more familiar with, metal that rusts because of the presence of water. There are different types of corrosion, but when we’re talking about a residential water heater, it’s the corrosion that occurs because of the mix of oxygen and water in contact with metal.
A water heater is designed to resist corrosion through a number of methods. The interior of its hot water tank is lined with glass. A pressure relief valve on the top of the tank allows for an air cushion without allowing air into the tank itself. A component called the sacrificial anode rod that runs through the tank draws the forces of corrosion to it so that the rod corrodes rather than the rest of the tank.
However… yes, a water heater can start to corrode. If you notice corrosion on your water heater, does it mean the system has to be replaced?
Corrosion Is Definitely a Serious Problem
We can’t give you a solid “yes, you must replace a water heater that’s corroding,” because it isn’t always the case. But it usually is. We can’t understate the seriousness of corrosion on a water heater: it puts the whole system at risk as it weakens the metal of the tank and of the connection points. If you have a gas-powered water heater, the corrosion can also affect the heat exchanger and the gas burners, cutting down on system effectiveness.
The short version: No matter what, if you spot corrosion on your water heater, call for professionals to look into it! They can decide if repairs can rescue the system or if it’s time for a new water heater.
If the corrosion is occurring on a single component—such as the heat exchanger—it is sometimes possible for technicians to remove the affected part and replace it. This is more likely to occur in a younger system. If the water heater is 15 years old or more, then any indication of corrosion means decline has permanently set in and it’s time to put in a new system. (A 15-year run is a good one! You’ve gotten your money’s worth.)
If the corrosion is starting on the tank—which you may notice in water discoloration from the taps or corrosion around the pressure relief and temperature valves—the system must be replaced. Don’t wait for the tank to start leaking: have professional help you with a new water heater right away.
Yes, Tankless Water Heaters Can Corrode As Well
You may have noticed that everything we’re talking about above assumes you have a storage tank water heater. However, corrosion can affect tankless water heaters as well. It occurs less often (there’s simply less contact between water and metal), but it can happen because of water dripping onto the gas burners. Corrosion on the burners will lead to them becoming blocked and less effective. You probably won’t have to have the system replaced in this case, however. Just make sure you keep up with regular maintenance and your tankless water heater shouldn’t have corrosion trouble.
Our plumbers offer extensive water heater services in Cleves, OH and throughout the Greater Cincinnati Area. Contact us at the first sign you need assistance—we have 24-hour emergency service.
Let our plumbing expertise at Ken Neyer Plumbing, Inc. help you with all your water heater needs!