Drain Pipe for undersink water filter

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britboy britboy

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I have water filter to install under my kitchen sink and i keep getting mixed answers as to where the drain pipe should be. I have two options:

1. Drill a hold here and attach the drain pipe (see photo 1)

2. Add this connector to split dishwasher drain with filter drain (see photo 2 and 3)

Noone can give me a straight answer on what to do.

Advice welcome. Thanks
 

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Is it a reverse osmosis drain? If so, they recommend installing past the p trap (at least mine required it)
 
Is it a reverse osmosis drain? If so, they recommend installing past the p trap (at least mine required it)
That doesn’t make sense to me. The trap is what separates you from the stink
 
I believe it has something to do with the constant noise from the R/O unit discharging water, and the gurgling you would hear if connected on the user side of the P trap.
 
I believe it has something to do with the constant noise from the R/O unit discharging water, and the gurgling you would hear if connected on the user side of the P trap.
I would say it needs it own trap then.

I would have to read what’s said in the manual but typically we don’t connect things on the sewer side of a trap.
 
My bad! You got me thinking deep, and realized you are correct. It was myself who thought it would be better to install the drain before the P trap, but I followed the instructions to a tee, and yep, it is before the P trap. My apologies to all for spouting before my second cup of coffee. The black line is the R/O waste line.20240729_092848.jpg
 
Is it a reverse osmosis drain? If so, they recommend installing past the p trap (at least mine required it)
Thanks for this. It is a reverse Osmosis. One video online showed before P Trap but i am assuming that drilling a hole in the black pipe is better than putting a two way connector where the dishwasher drains (see pic above with red arrow)?
 
Thanks for this. It is a reverse Osmosis. One video online showed before P Trap but i am assuming that drilling a hole in the black pipe is better than putting a two way connector where the dishwasher drains (see pic above with red arrow)?
Yes, and if for any reason I want to eliminate the pipe with the hole drilled into it, they cost about $2 at a big box store.
 
Using the adapter you show in picture 3 to drain your filter into the dishwasher line to the garbage disposal would be my choice. You really don't want materials from the garbage disposal to be flying into the drain line from the filter, but the flowing the filter water into the garbage disposal will be just fine.
 
I'd be concerned of back pressure feeding backwards up into the R/O system and would also recommend staying clear of the disposal connection.
 
I'd be concerned of back pressure feeding backwards up into the R/O system and would also recommend staying clear of the disposal connection.
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Just guessing at some flow rates, that pressure drop will be less than a half inch of water column. So just install that fitting pointing up and there won't be any backflow to the filter.
 
I would use the dishwasher drain tee in this case, as connecting to the disposal outlet could lead to higher chance of clogging or issues.
 
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