Do I really need to replace the anode rod?

Question

Whenever I look online for information relating to anode rods in a water heater, they most often say they should be replaced regularly (4-5 years). However, every single plumber I have talked to has told me that they rarely replace the anode rods or they don't at all and I shouldn't worry about it.

So what's the deal? Is it important to replace the anode rods?

What brought this to my attention is that my hot water tastes very metallic but the cold water doesn't. I have a well, water softener, and a particulate filter system (three, 20" filters). The water heater had a lot of sediment when I recently emptied it and I have been noticing certain copper pipes have a lot of green corrosion in some spots. The water heater is 12 years old.

Answer 1

Most water heater tanks are steel with a thin glass lining to protect the metal from corrosion. Since the lining eventually cracks, tanks have a second line of defense against rust: a long metal “anode rod” that attracts corrosive elements in the water. When the rod itself becomes so corroded that it can no longer do its job, the tank soon rusts out, leaks and needs replacement. However, if you replace your water heater anode rod before it fails, about every five years, you can double the life of your water heater.

_source

The fact that plumbers don't often do this shouldn't be taken as an indicator that it isn't important. The homeowner may not be aware of the purpose of the rod or the resulting benefit from changing it, so they don't ever call the plumber to do it. Few plumbers are going to maintain service records and call you to suggest you have it done.

The guidelines for replacement are averages and your situation may be different. You can either 1) change it on a fixed schedule and hope that's often enough, or 2) change it when you're under the impression that it's not doing its job.

In short, it's up to you.

Answer 2

The purpose of the anode is to corrode first before your tank does. It may be that your water chemistry is such that the anode is only consumed slowly (or absurdly fast-- one of our clients had an anode go from 1" diameter down to the steel core in a few weeks due to their chemistry problem). If you check the anode periodically and see little change from when it was new, and the inside of the water tank isn't showing a lot of rust, then you can leave it until more of the anode magnesium or aluminum is consumed.