This is a follow up to my post last week about moving the washer box. I have a plan for that but need to find a better arrangement for the softener drain line that appears to have been improperly connected to the washer drain.

Here is a wide view of the space I am working with. You can see the washer box on the far wall and the utility closet on the left.



Opposite the laundry wall where I'm standing is a 1/2 bath. The closet flange has a rag stuffed in it and the horizontal drain connects to the lav that is getting replaced. The toilet is wet vented from the sink. Vertical 1-1/2" pipe goes up to an AAV that remains accessible above the suspended ceiling.



Question: Can I tee into the toilet vent above the sink (or below?) and add a trap/standpipe for the softener drain and reverse osmosis drain?

I'd like to bring that standpipe into the utility closet where it's accessible, and I have room in the corner right in front of the well expansion tank. Thoughts?

Is there a reason you can not use the floor drain to the right of the water heater to drain softener/RO system etc. ?

Hi Curly, the RO drain and the a/c condensate drain were directed into the floor drain when we bought this 1980 house 5 years ago. We've had some issues with the drain not draining causing water to pool and I posted about it last summer with some better pics: [www.plbg.com]

I'm not sure if that floor drain ties into the sump pit in the crawl space or the toilet line going to the septic. I have a cheap waterproof endoscope that I picked up on Amazon for $20, I was going to send that down the drain to see if I can see anything but haven't done it yet. The fix over the summer was to route the a/c drain through the wall and drain it in the garden, and I had the RO line draining into the toilet tank.

Since I pulled the toilet I put the RO drain back in the floor drain and so far it hasn't overflowed. From what I can tell, the drain is partially blocked by something, could be rust, and the volume of condensate during the hot summer months overflows it. Current plan is to leave it alone unused rather than attempt to jackhammer the floor and replace it. I'm concerned that if it's rusted, I could make the issue worse trying to snake it.

Once I pulled the wall behind the laundry appliances, and saw the softener drain, I figured this was a good time to explore other options since the washer box needs to get moved. If I can drain the softener and RO into a standpipe I can just leave the floor drain alone.

There is likely a trap under the floor drain and I doubt an endoscope will thread through a trap.

Looks like you have a cleanout plug next to the floor drain. Could remove that and inspect piping/snake etc. and see if problem is in the trap on farther down the pipe. If you have a hard time getting plug out, see Tom the Elder's post for help.

I have used one of these fittings under a sink for AC condensate, tankless condensate and water softener drain.

They make them in air gap style and non airgap style. A little pricey but well made and multiple point of connections were easy to connect.

[vistawatergroup.com]

They make washing machine drain boxes with different configurations for washing machine drain, water softener etc.

Sometimes a little tough to figure out just what you need, but maybe worth a look...

Search for "Washing machine boxes



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I like the drain gap fitting, thanks for posting. If I use that am I OK to tee the standpipe into the toilet wet vent as planned? Does it matter if I tap in above or below the lav?

If you remove the existing san tee and replace it with a double san tee you would be code compliant in my area,

If you use the double san tee I would try and install a clean out on vertical pipe because it is tough to get a snake to go down a double san tee if you have a stoppage. The snake wants to just go across the tee. I would install clean out above double san tee.

I'm not as well versed on wet venting as some of the other guys on this site....That being said I don't see it as a major problem adding a tee above or below the existing tee. I don't think it is code compliant in my area...but it should work OK.

My understanding with wet venting is that it you have a lot of water flow, it can suck water out of the trap. I don't think you will have a lot of water flow.

How about omitting the AAV and tie the vent pipe for the WC, lav and softener into the vent for the laundry? The ceiling's already open and going to be a dropped ceiling. Is that vent pipe for the toilet 1 1/2"?



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Curly, that pipe will be enclosed in a wall, so a cleanout won't help...why I'd prefer to have separate san tees vs. a cross tee if code allows so the line can be snaked through the trap if needed.

Steve, I thought about tying those vents together and losing the AAV. Horizontal distance is 11', although I do have the height to do the 1/4" per foot slope. Does code restrict how far vents can run horizontally? Tried Googling and the answers were all over the place.

The horizontal run length(in this scenario) doesn't matter.

Just finished the relocation of the washer box and cut the softener drain line out of the washer drain. Here's a look at the inside of that drain line:



I'm adding a 30 micron pleated filter ahead of the softener to cut down on some of the iron residue. One surprise was the fact that the softener drains continually, which according to a quick Google means it's not working properly. We had it serviced about 2 yrs ago and the tech mentioned that a valve was clogged with iron residue.