RO/DI Drain Line to 2” Drain Pipe?

[Zach W]

I am looking to direct plumb my RO/DI system to my water supply in the basement. I am also looking to tap into a drain line in the basement since there is no sinks or anything in the basement to drain into. Unfortunately the normal 1.5”” saddle valve drain ports are too small for the drain pipes that are accessible. Can I just drill a 1/4” hole above one of the P traps and use some waterproof silicone caulk to prevent any leaks and keep it in place? Has anyone done this?

 

[basementreef]

You can but it’s not ideal it’s definitely against code and the tubing hanging inside the drain may cause future clogs however There is a better way :

Everbilt 1-1/2 in. x 8-1/2 in. White Plastic Slip-Joint Sink Drain Tailpiece Extension Tube with Hi-Line Branch C9818 - The Home Depot

Securely connect your dishwasher to a drainage system with the Everbilt Plastic Branch Tailpiece. Made of durable polypropylene material, it has a 10 psi max of working pressure. Features a Hi-Line connection

www.homedepot.com

You will have to reduce the 1/2 to accept your 1/4 ro line. There’s barbed fittings and hose clamps for that goodluck

 

[homer1475]

I did this exact thing.

Only thing I did different was to drill and tap my waste line to accept a 1/4" screw in john guest fitting.

John Guest 1/4 in. O.D. x 1/4 in. MIP NPTF Polypropylene Push-to-Connect Adapter Fitting 803219 - The Home Depot

The John Guest 1/4 in. O.D. x 1/4 in. NPTF Push-to-Connect Male Connector is manufactured from white polypropylene and equipped with EPDM O-rings utilizing John Guest's push-fit technology to make an easy, reliable, leak-free connection. Developed to satisfy a wide range of applications it can...

www.homedepot.com

 

[Zach W]

You can but it’s not ideal it’s definitely against code and the tubing hanging inside the drain may cause future clogs however There is a better way :

Everbilt 1-1/2 in. x 8-1/2 in. White Plastic Slip-Joint Sink Drain Tailpiece Extension Tube with Hi-Line Branch C9818 - The Home Depot

Securely connect your dishwasher to a drainage system with the Everbilt Plastic Branch Tailpiece. Made of durable polypropylene material, it has a 10 psi max of working pressure. Features a Hi-Line connection

www.homedepot.com

You will have to reduce the 1/2 to accept your 1/4 ro line. There’s barbed fittings and hose clamps for that goodluck

I’m not a plumber so maybe I’m just confused but this looks like it’s for an under sink application. I am looking to tap into a main drain line that is actually coming off of a bath tub above. I don’t think this would work for that

 

[Zach W]

I did this exact thing.

Only thing I did different was to drill and tap my waste line to accept a 1/4" screw in john guest fitting.

John Guest 1/4 in. O.D. x 1/4 in. MIP NPTF Polypropylene Push-to-Connect Adapter Fitting 803219 - The Home Depot

The John Guest 1/4 in. O.D. x 1/4 in. NPTF Push-to-Connect Male Connector is manufactured from white polypropylene and equipped with EPDM O-rings utilizing John Guest's push-fit technology to make an easy, reliable, leak-free connection. Developed to satisfy a wide range of applications it can...

www.homedepot.com

Good to hear that someone else has done it! So if I’m understanding correctly you drilled into your drain line and tapped the hole for threads. What did you use, if anything, to seal the face since the pipe is rounded and the fitting is flat? Thank you!

 

[homer1475]

Did nothing but put some teflon tape on the threads, and screwed it in tight. Hasn't leaked in 4 years. This is also on a main line that is horizontal, and the only way I could get to it is to tap the bottom so water is always rushing past it, and it hasn't leaked yet.

 

[Zach W]

Did nothing but put some teflon tape on the threads, and screwed it in tight. Hasn't leaked in 4 years. This is also on a main line that is horizontal, and the only way I could get to it is to tap the bottom so water is always rushing past it, and it hasn't leaked yet.

Ah ok, for instance this is the line I was thinking of tapping into. I read somewhere it should be above a p trap but maybe that’s not true

 

[homer1475]

if you are going to tap into that line with the P trap, do it above the P. This way it never has water sitting in the pipe and on the fitting. Waste gas wouldn't be an issue since the Ro/DI waste line is never allowed to "breathe".

The idea behind the "above a P trap" is so noxious waste gasses cannot enter your house. Since the waste line is never exposed to air(always connected) there is no concern there.

 

[Zach W]

Ok, great. Thank you for the help!! @homer1475

 

[homer1475]

No problem, glad to help.

 

[basementreef]

I’m not a plumber so maybe I’m just confused but this looks like it’s for an under sink application. I am looking to tap into a main drain line that is actually coming off of a bath tub above. I don’t think this would work for that

Sorry when you said p trap I automatically thought you me t a trap under a sink

 

[YOYOYOReefer]

if you need to use a sealant i recommend JB WaterWeld , it works for lots of things in this hobby

 

[mnl119]

Ah ok, for instance this is the line I was thinking of tapping into. I read somewhere it should be above a p trap but maybe that’s not true

I'm looking at your p-trap and thinking even the lines above the trap will be full of water. Both of those PVC pipes slant downward.

 

[Zach W]

I'm looking at your p-trap and thinking even the lines above the trap will be full of water. Both of those PVC pipes slant downward.

Here is a side view of the line I'm thinking of tapping into, this photo is misleading with that other drain line coming down.

 

[mnl119]

Here is a side view of the line I'm thinking of tapping into, this photo is misleading with that other drain line coming down.

Ahh, that makes more sense now. Are there any cleanout covers anywhere in the line? I've tapped into those before and they are easily replaced if you change in the future.

 

[homer1475]

Ahh, that makes more sense now. Are there any cleanout covers anywhere in the line? I've tapped into those before and they are easily replaced if you change in the future.

From his first picture, that front line with the Y in it, has a clean out in the end.

 

[KStatefan]

Above the p trap would be a better place then that clean out.

 

[mnl119]

Above the p trap would be a better place then that clean out.

I can understand the desire to be above the p-trap from the standpoint of not letting sewer gasses escape, but it' not like he's putting in an open drain. It will be a sealed system. Going through a cleanup cap saves the option of easily (i.e., in 5 minutes) going back to the unaltered state for the system if he wants to move his RODI unit in the future.

Maybe there is another cleanup cap somewhere above the p-trap that is not pictured that would satisfy both desires?

Edit: The location of the cleanup cap pictured looks like a 3" toilet drain. I probably wouldn't want do deal with that either.

 

[Gtinnel]

I have drilled a 1/4 hole and put a drain line (from my AWC) into it with silicone. The silicone will not adhere to the pvc very well. I would definitely use @homer1475 suggestion and add an adapter that you thread in. I think I’m going to change mine out to that too.

 

[Zach W]

I can understand the desire to be above the p-trap from the standpoint of not letting sewer gasses escape, but it' not like he's putting in an open drain. It will be a sealed system. Going through a cleanup cap saves the option of easily (i.e., in 5 minutes) going back to the unaltered state for the system if he wants to move his RODI unit in the future.

Maybe there is another cleanup cap somewhere above the p-trap that is not pictured that would satisfy both desires?

Edit: The location of the cleanup cap pictured looks like a 3" toilet drain. I probably wouldn't want do deal with that either.

The cleanout is from a toilet line in the upstairs bathroom. The p trap shown is right below the downstairs bathtub that is only ever used when we have guests. I have the materials to do the method @homer1475 described above the the 1/4" push to 1/4MIP fitting I just haven't gotten around to install it yet