Water Heater Anode Rods 101

How Can We Fix Smelly Water?

Smelly water is typically caused by the origin of the water. Sulfur is another common mineral found in water, often responsible for causing a rotten egg smell. A.O. Smith recommends several fixes for smelly water: increasing the temperature on the gas control valve or thermostat above 140 degrees (recommended temperature setting is 150 degrees) and installing mixing valves at each point of use to kill any bacteria; engaging in a chlorine treatment, and changing the anode rod from magnesium or aluminum to one made of zinc-aluminum alloy. In some cases, using the wrong anode rod in certain types of water can result in a chemical reaction, where non-harmful sulfur reducing bacteria produce smelly water.

One of the commonly used zinc-aluminum anode rods our technicians install is an A.O. Smith KA-90 Anode Rod (100108571). This type of anode has helped many of our well water based customers rid their homes of the smelly water (see image slider).

How Do I Know if I Have Hard Water?

You can easily determine whether you have hard water by performing a PH Test on water samples from your home. When you dip the test strip into the water, your result should read around a 7. If your strip does not match the green/neutral area on the test kit chart, you likely have hard water. Example Test Strip Kit

How Often Should an Anode Rod Be Checked?

Anode Rods should be checked on an annual basis. Manufacturers often recommend annual anode rod checks as part of the annual preventative maintenance, but heaters operating on well water will likely need additional attention.

How Do I Know When to Change My Anode Rod?

Anode Rods with noticeable sediment build-up and/or corrosion should be changed, especially if your anode rod is corroded down to the steel wire. Sediment build up on the anode will be easily noticeable, just as it is on an element. If you have an electric heater and you notice sediment/corrosion on your anode rod, you may also want to consider having the elements checked and possibly replaced. See below for an example of the stages of anode rod depletion.

Can Anode Rods be Replaced?

Yes, the heater must be drained below the anode rod. The technician will then unscrew and remove the old anode rod, which will likely show signs of corrosion. In some rare cases, the amount of build-up around the threading of the anode rod may prevent anode rod replacement. The technician will also need some headspace above the heater to clear the old anode rod's removal and to insert the new one. If you do not have sufficient space for the new traditional style anode rod, you may opt for a flexible anode rod such as the A.O. Smith 100110784 (Magnesium Flex Anode Rod) or 100110627 (Aluminum Flex Anode Rod). Although there is a large variety of anode rods across the major manufacturers, our technicians all carry the A.O. Smith KA-90 Anode Rod (100108571) as part of their regular truck stock and we also maintain a small stock of the Magnesium Flex Anode Rods in our warehouse as well. 

How Much Will the Anode Rod Cost?

Standard anode rods tend to cost anywhere from $50-$150, averaging about $75 each. If you are contacting a service provider to change your anode rod, you can save some money on labor costs by draining the tank yourself and having a technician install the anode rod. Powered anode rods (typically found in commercial units) are usually more expensive and can cost upwards of $300 apiece.