I have this of water filtration setup in my house. It was like this when I bought the house and a couple of plumbers have told me it's weird. Images I noticed yesterday that the filter closest to the water heater was leaking. I replaced the o ring and the filter, and cleaned the canister threads. When I put it back together, I realized it's leaking under the cap, so it seems to be coming from the housing itself, so I think I will have to replace...
Originally asked by Mike on Stack Exchange (diy) (CC BY-SA 4.0).