Friday, June 5, 2015

Can I Use a Water Heater as a Chlorine Contact Tank?


Do you see any issues with using a water heater as a chlorine contact tank?  I have a spare water heater not being used. We have an electric water heater that we replaced recently with an oil-fired on-demand heater.  If we did that, the heating function of the heater would not be used –  cold water in and cold water out.

I read some comments on the internet about drinking water from a hot water heater and the only possible issue I saw with this concept was about anodes  in the heater adding metals to the water – not sure if the heater even has an anode?

John O

Dear John,

We’ve heard of people using a water heater as a contact tank, sure.  That seems to work out pretty well depending on the construction of the tank and where the inlet/outlet are oriented.  Ideally, the water should enter through the bottom and exit out the top for best retention and mixing.

Make sure to leave the anode rod installed for corrosion protection.

Water heaters are metal tanks, but they have a  glass lining.  If a tiny part of the glass wears off or is imperfect, the metal tank develops a leak in a few months.  The anode dissolves some magnesium and the metal tank is the cathode (like a battery).   The metal flows from the anode to the cathode and seals up the glass imperfection.

Also make sure there is a way to drain the water heater contact tank from time to time. It is important to be able to drain it so as to clean out sediment and deposits that can develop.

anode rod installed for corrosion protection