Replace anode to give your water heater a longer life

Most people who've owned a house for a while have had to replace a water heater. With an average life of roughly 10 to 15 years, they fail often enough that your turn to put one in is coming. You can forestall that day if you're willing to take the trouble or expense of replacing some parts on it every five or six years.

The key part is the anode, a metal rod inside the water heater that serves to prevent the steel tank from rusting. If you know boats, you probably know about anodes - propeller shafts typically have a chunk of zinc clamped onto them as a sacrificial anode to prevent corrosion. The anode in a steel (e.g., glass-lined) water heater is essential to prevent the tank from rusting out, and once it is depleted the water heater will fail in short order.


The anode in a water heater is magnesium or aluminum, it's usually screwed into the top of the water heater and it has a hexagonal head. Less commonly, it is installed in the fitting that the hot water outlet pipe connects to. Either way, it is usually replaceable, and replacing it every five or six years can extend the life of a water heater to 20 or 30 years.

The cost savings of replacing the anode periodically over replacing the entire water heater is significant, 70 percent by one estimate.


It seems fairly obvious that everyone should do this, or have it done. People have the oil in their car changed at regular intervals, so why not perform preventive maintenance on home appliances? The short answer is that water heaters don't cost as much as cars, and people are generally satisfied if they get only 10 years out of a water heater.

Also, while anode replacement schedules are fairly common in commercial buildings, the practice is so uncommon with residential water heaters that it's not a service that I've ever heard a plumber offer, and you can't buy a replacement anode at the local hardware store. But you can order one, and they don't cost that much - about $50. Sources include plumbing supply companies and the Internet. If you're going to that length, go ahead and replace the dip tube at the same time. It's the other component that's most likely to fail.

The procedure is not complicated. It basically requires draining the water out of the water heater using a hose connected to the drain valve at the bottom, then installing the new parts. But it can be difficult, especially if the existing anode has been in for more than five years and is stuck or if the water heater has a cheap drain valve that doesn't operate properly. Hiring this job out to a plumber can make good sense, and the project will still be cost-effective.

You can learn more about this online and even order the parts if you decide to take it on yourself.

For more information online, check out the following sites: www. or www. htm

Inspector's Eye

Dean Uhler has been a home inspector for more than 12 years and is president of Baltimore-based Boswell Building Surveys Inc. Uhler is a member of the American Society of Home Inspectors (ASHI) and is the treasurer of the Greater Baltimore Chapter of ASHI.

Questions, with name, address and daytime telephone number, about homes and home inspections can be faxed to 410-783-2517, e-mailed to or mailed to Inspector's Eye, Second Floor, 501 N. Calvert St., Baltimore, Md. 21278-0001.