How long does a water softener last? Great Question. I have seen water softeners last anywhere from just a few years up to 30 years. The cheap Chinese or Korean ones sold at big box stores are the most likely to have a short lifespan of about 3-5 years but occasionally you might see a few more years if you're lucky. These ones are pretty much disposable as trouble shooting information is vague and incomplete as well as parts availability is very poor. Finding a repair manual or parts list for these is impossible. Typically the ones with the longest lifespan are Made in USA like the very popular ones using Clack WS1 valves or the ones that have been manufactured for generations by companies like Hague who produce the Aquamaster/Water Boss water softeners. These have great manuals, a great dealer support network, replacement parts availability and lots of how to videos on YouTube as support to correctly install them yourself or help you or your dealer trouble shoot if you run across a concern. I have seen many Clack and Aquamaster/Water Boss water softeners last well over 20 years. Far too often a water softener fails merely because there is no one available that can problem solve and repair, also replacement parts are not easily available so investing in a water softener that has good support is very important.