Not sure if I've talked much about our water treatment system. The same week we moved in we had an Iron Shield with Toxin Guard filtration system installed by Easywater. It doesn't use chemicals or anything it simply removes stuff from the water and then every couple of night does a backwash to clean itself. (pictured below, tall black tank).
It only uses a few watts of power for the lit display, it uses a little more power to run the pumps during backwash cycle but only about like running a light bulb for the time it does the cleaning.
My latest addition as of yesterday 2/15 was an electronic descaler (water softener). This was an easy do-it-yourself addition, it uses wire coils wrapped around the incoming water supply line, it then creates a magnetic field which changes the physical structure of calcium and other elements that cause hard water. It doesn't remove anything from the water like the salt systems but at the same time it doesn't add back anything either, like salt. The modified elements are supposed to be less "sticky" after passing through the coils so that they don't build up or bond to surfaces. They say it may take a couple months before we notice the difference, so more to come on this one.
Update: for those curious it does run continuously but only uses 3 watts of power, I check and track everything I plug in to see what the power consumption will be.