About 3 years ago, I had my water heater replaced (after the first tank was 15 years old and the second one lasted about 7 years) and had a new water pressure expansion tank installed.
Last month I wandered past the water heater and noticed a small amount of water on top of the water heater. I noticed the expansion tank was a little rusted out near the connection and a slow drip of water coming out….after only about 3 years! When I asked 3 different plumbing contractors to quote on a replacement, each told me those tanks don’t seem to last more than 3 years….Why not?
With water heaters lasting only 6-7 years now and expansion tanks lasting < 3 years, some plumbers may not want the risk of just installing a new expansion tank on an older water heater without replacing both devices at the same time. But even if they will install it, it's now going to be at least a recurring homeowner expense anywhere from $220-300 every few years. Maybe this will create an incentive to install a tankless water heater, but that still costs thousands in plumbing (supply line and exhaust) and installation costs...but so will the constant change of water heaters and expansion tanks. Is this another conspiracy (making systems that last shorter periods) against homeowners? Should we storm the water heater and expansion tank manufacturers to let them know they should make them last longer? Only time will tell and enough angry consumers but for now it is just another back door charge to homeowners and homeownership expense to consider. As a side note, our county (Cobb) water system is installing back flow preventer water valves (to prevent water backing up into water system that may be contaminated from homes) on the water supply lines to our homes. Residents are advised to have the water expansion tanks installed on their water heaters to prevent problems with the additional pressure if a back flow were to occur.