Please Review My Drain Plans for AWC and RO

SPSReeferMI · Oct 29, 2019

Hello,

I’m planning to cut into my existing home’s drain vent and I’d like to hear from anyone with plumbing experience if I’m approaching this correctly. I’m not a plumber, so I likely won’t be using the right terms here.

My problem: I have just setup an AWC in my basement and I’d like the saltwater to drain directly into my home’s drain vent. And, if I’m doing this I might as well plumb my RO waste line in here as well. I could hire a plumber, but this is such a small job.

The plan: I have a 2” vertical drain vent in my current setup (see the red arrow in the image below). I plan to use a 2” x 1.5” tee and from this tee I can add PVC to the right to create 2 John Guest valves for each drain. I plan to use (2) 1.5” Slip by 1/2” FPT tees with the FPT for the John Guest valves to point up. I may not be describing this properly, but the John Guest valve would be inserted in there using plumbers tape.

My questions:
1.) Can I safely cut my drain vent by the red arrow (see image) and plumb my john guest valves there?
2.) Is there any reason why I can’t use a John Guest tee and then go into the PVC drain? AWC and RO drain plumbed together.

Thanks in advance!

link81 · Oct 29, 2019

they also make saddle back's where you basically glue half of a tee to the existing pipe then drill a hole. Prevents you from having to cut the pipe.

only issue i see with doing it there, is that the salt won't get washed away. over time the evaporated water and salt could plug the pipe.

How often does your sump pump run? i might think about putting it on top of that sump pump line.

here's an example, they should be easy to find locally in the plumbing section.

Pvc Saddles For Phytomist - For 3/4 In. Diameter P

Cement saddle to PVC pipe to mount Phyto-Mist Nozzles to schedule 40 or 80 PVC pipe. Requires 5/16" hole in PVC for installation.

www.greenhousemegastore.com

SPSReeferMI · Oct 29, 2019

link81 said:
they also make saddle back's where you basically glue half of a tee to the existing pipe then drill a hole. Prevents you from having to cut the pipe.

only issue i see with doing it there, is that the salt won't get washed away. over time the evaporated water and salt could plug the pipe.

How often does your sump pump run? i might think about putting it on top of that sump pump line.

here's an example, they should be easy to find locally in the plumbing section.

Pvc Saddles For Phytomist - For 3/4 In. Diameter P

Cement saddle to PVC pipe to mount Phyto-Mist Nozzles to schedule 40 or 80 PVC pipe. Requires 5/16" hole in PVC for installation.

www.greenhousemegastore.com

Thank you for the quick reply. And yes, that is a good point about salt build up. I could modify my plan to make sure that the AWC drain is below my RO waste drain.

I would love to use a saddle valve, but they do not make 2” saddle valves to my knowledge... and most people don’t like them. Also, I plan to sell my home in 2-3 years, so I’m thinking through inspection time.

link81 · Oct 29, 2019

Scott MacDonald said:
I would love to use a saddle valve, but they do not make 2” saddle valves to my knowledge... and most people don’t like them. Also, I plan to sell my home in 2-3 years, so I’m thinking through inspection time.

they definitely make them, might be an amazon item. I'm pretty sure they are up to snuff with all building codes. they are glued on just like a regular PVC fitting.
but at any route, if you're going to mount the RO line above in, then i don't see any issue with cutting the vent, and extending up up high enough to add a couple of tee's. one for RO and one for salt.

Prime, can have it in 2 days... no idea how amazon does it, but whatever.

SPSReeferMI · Oct 29, 2019

link81 said:
they definitely make them, might be an amazon item. I'm pretty sure they are up to snuff with all building codes. they are glued on just like a regular PVC fitting.
but at any route, if you're going to mount the RO line above in, then i don't see any issue with cutting the vent, and extending up up high enough to add a couple of tee's. one for RO and one for salt.

Prime, can have it in 2 days... no idea how amazon does it, but whatever.

Thank you! I’ll consider this.

Any thoughts on cutting my vent at that location? I cannot think of how that would be a problem, but I always like a second opinion when it comes to plumbing.

link81 · Oct 29, 2019

Nope,
I don't see any issues.

foxt · Oct 29, 2019

Whenever you modify your DWV system, you want to be sure to add a trap between the vent line and the additional drain to prevent sewer gas from entering the house.

Just trying to get a better sense of what we are looking at. I noticed that you have an AAV on top of the vertical pipe - was that added at some point? Is that a sewage extractor line coming in from the right? Is that a check valve in the drain line between your main stack and the vertical pipe you want to cut?

SPSReeferMI · Oct 30, 2019

foxt said:
Whenever you modify your DWV system, you want to be sure to add a trap between the vent line and the additional drain to prevent sewer gas from entering the house.

Just trying to get a better sense of what we are looking at. I noticed that you have an AAV on top of the vertical pipe - was that added at some point? Is that a sewage extractor line coming in from the right? Is that a check valve in the drain line between your main stack and the vertical pipe you want to cut?

That’s right - I believe that it was added when my basement was finished. This wall is near the front of the house - so I’m guessing that there was not a convenient roof vent. One line from the right is the extractor and another is the sump. I am not sure if that is a check valve, I assumed that was access in case of blockage.

foxt · Oct 30, 2019

It's an odd looking fixture, so I was wondering what it was. FWIW, if this was my setup, I'd want to just be sure about what that is before I disrupted what is in place.

link81 · Oct 30, 2019

I was thinking it might be a horizontal cleanout, but the impressions on the side of the fitting look like it might be a check valve as well.
the entire setup looks a little odd, the vent is low, and i only see a single trap. shouldn't there be a main trap right before the dvw exits through the foundation?

foxt · Oct 30, 2019

No, you don't need a "main trap" before the stack leaves the foundation - each fixture needs a trap.

Just speculating, but if that is a check valve, I would wonder how it would operate with RO/DI waste trying to run through it?

KStatefan · Oct 30, 2019

link81 said:
I was thinking it might be a horizontal cleanout, but the impressions on the side of the fitting look like it might be a check valve as well.
the entire setup looks a little odd, the vent is low, and i only see a single trap. shouldn't there be a main trap right before the dvw exits through the foundation?

It is a check valve they are used a lot in kitchen islands but do not meet code in many places

foxt · Oct 30, 2019

KStatefan said:
It is a check valve they are used a lot in kitchen islands but do not meet code in many places

I think you may be referring to the automatic air vent (AAV) that is at the top of the section that the OP is looking at cutting. We're speculating as to the fitting right before the main stack, looks like a check valve to me which would make sense since that's a sewage ejector coming in from the right side. Only question I have at this point is what reaction a check valve is going to have when RO waste encounters it. Depending on the type of check valve, low flow, low volume such as coming from RO waste may not actuate the valve, which will cause water to start to back up towards the trap for the ejector.

link81 · Oct 30, 2019

@Scott MacDonald
This is what you're proposing correct??

KStatefan · Oct 30, 2019

foxt said:
I think you may be referring to the automatic air vent (AAV) that is at the top of the section that the OP is looking at cutting. We're speculating as to the fitting right before the main stack, looks like a check valve to me which would make sense since that's a sewage ejector coming in from the right side. Only question I have at this point is what reaction a check valve is going to have when RO waste encounters it. Depending on the type of check valve, low flow, low volume such as coming from RO waste may not actuate the valve, which will cause water to start to back up towards the trap for the ejector.

I was didt even notice that. Seems like a strange way of plumbing sewage ejector pump

SPSReeferMI · Oct 31, 2019

link81 said:
@Scott MacDonald
This is what you're proposing correct??

Sorry for the delayed response!

This is very close to what I'm suggesting. I will tee valve off to the right, but it's effectively what you have.

Also, that is a horizontal cleanout access, not a check valve from what I can tell.

Thank you all for your ideas.

SPSReeferMI · Oct 31, 2019

Here are the parts I plan to use.

foxt · Nov 5, 2019

It is an odd looking clean out, but if you are sure, then so be it. Best way to be sure is just remove the cover.

For the configuration you’re posting, you want a trap between the vertical tee and the first tee with the tubing fitting in it. Someone decided that you needed an air vent for the sewage ejector to work properly, and you want to make sure that you aren’t just creating a new vent path with what you are adding.