I'd like to install a water softener in my house. I have a good idea of what's required, but I'd like to know if I'm overlooking anything.

I have city water coming into my basement through the floor of a small closet:

Closet Sketch

Near the city water input there is also a drainage stack for a 1st floor bathroom. It has a cleanout about 12" from the floor.

Closet photo

I'd like to build a platform such that the water softener could be drained into the existing stack:

enter image description here

Am I overlooking anything?


Yes, You have neglected to show how any particular sized water softener would fit onto a shelf table size of 15" x 20"; let alone get it into that space.

Also you will need a riser on the softener side of the P-Trap that you have shown there. Seems to me that there will also need to be a guaranteed airgap between softener drain line and P-Trap riser. If this were practical you may want to consider placing the P-Trap fitting below the cleanout or combine it in with a replacement for that fitting.

Lastly it seems like it will be a major pain to get access to the softener unit when elevated like that to service it. Service can include having to add softener salt to the tank for some units. For salt-free units that have 3-5 year replaceable resin type canisters the overall height of the unit may be a problem.

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    And, when considering the height, make sure you can lift anything you need out the top without hitting the ceiling. – Daniel Griscom May 30 '16 at 22:08
  • What do you mean by "you will need a riser"? Does that just mean I need a length of straight pipe above the P-trap? – T.D. Smith Jun 1 '16 at 1:58
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    @Tyler - Yes. Any type of drain hose similar to what comes out of cloths washer needs to have its hose coupled into a riser that is above the P-Trap so that there is enough height for the water to flow into the trap instead of gushing out like it would in your picture. The riser also provides an air gap to resist a siphon action back into the softener unit. Of course your unit may have instructions to hard plumb it to the trap and take care of any air gap requirement internally. – Michael Karas Jun 1 '16 at 3:14

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