Installing air gap on washing machine drain

[at_hiker]

I was planning on tying into my washing machine drain stand pipe to add an air gap for my water softener. My original plan was to cut the drain about half way down. Add a sanitary tee, reduce to 1 1/2”, p-trap, 18” stand pipe, topped with a verneco air gap. Then it occurred to me that the washing machine drain already has a p-trap, so I’m assuming that I don’t need an additional one? Do I need to place the sanitary tee any certain way to prevent washing machine water from coming up through the water softener stand pipe?

 

[Master Plumber Mark]

you can just cut that stand pipe down about a foot below where the hose goes
in and install a wye or a tee and just throw an arm wit an elbow or 45 on it and
go up maybe 6- 12 inches above the standpipe..... and just throw the water softener drain into that higher pipe..... that is technically a great , + the best kind of air gap and actually

the air gaps you buy at the store... those normally spit some excess water off the sides
at the top where it connects and then you have a return service call

You really dont have to do anything if you dont want to....
I see many water softener drains just stubbed into the washing machine
drain with the hose just take the ws hose up as high as possible
and then back down into that pipe

it will work

 

[Sponsor]

 

[Reach4]

Washing machines are special. They have their air gap built in, so no additional air gap is needed. Feeding the drain hose into the standpipe a bit, as you did, is OK for just a WM.

But to add a softener drain, you could make the top of the standpipe even, and add an appropriate commercial air gap made for softeners and WMs to share a standpipe.. Is that standpipe 2 inch or 1-1/2 inch? Or do as Master Plumber Mark said. That sounds cheaper.

 

[Bannerman]

A washing machine does not supply potable water whereas a water softener and other water treatment devices do.

To reduce the risk of cross contamination to the water treatment device due to a blockage or backup from the home's drainage system, an air gap is utilized to provide a physical separation between the water treatment device drain line and the home's drainage system so that contaminated effluent cannot be drawn back into the treatment device through its drain line.

 

[at_hiker]

Washing machines are special. They have their air gap built in, so no additional air gap is needed. Feeding the drain hose into the standpipe a bit, as you did, is OK for just a WM.

But to add a softener drain, you could make the top of the standpipe even, and add an appropriate commercial air gap made for softeners and WMs to share a standpipe.. Is that standpipe 2 inch or 1-1/2 inch? Or do as Master Plumber Mark said. That sounds cheaper.

It’s a 2” stand pipe

 

[Jeff H Young]

I would describe what mark mention as a high loop drain , I would expect that to work fine. High loop drains wont slide by inspectors here but its done in many places with approval no problem at all.
Some people might create a true airgap but others just stuff it in like they do dishwashers (again not getting by here that)

 

[Reach4]

I would tend toward https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Air-Gap-AG140-001-User-Guide.pdf
Upside down in the photos in https://www.supplyhouse.com/Air-Gap...ine-Box-w-1-2-PVC-Slip-Inlet-and-2-Drain-Pipe