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My house doesn't have P trap for kitchen sinks/bathroom sinks etc..

So instead of placing a p trap for each. May I just place one big p trap where the water is discharged from the building to outside.

FYI:

During the building construction plumber refused to add P trap fearing this could clog up the line so he didn't install

Update:

The town doesn't have underground sewer system , so I have to discharge waste water( Non-septic) in our own soak pit.

So this brings a question that do we still need a P-Trap in the first place ? because there's no external pressure to push back any gas and regarding water seal in the P-Trap,can it really stop the ingression of pests ? .. I'm not sure. So I'm wondering do we need any P-Traps except septic line.

CuriousMan
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1 Answers1

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Typically you want P-Traps at every sink. If the drain goes straight down into the floor, you want to avoid S-Traps. Instead you can install an Air Admittance Valve to avoid the drain suction issue that may pull all of the water out of an S-Trap.

BMitch
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Ernie Albus
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  • If I am using P trap .. would I still need to go with Air admittance valve ? – CuriousMan Apr 09 '23 at 18:09
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    in general, no - P-traps that connect properly / horizontally connect into the plumbing stack which does the same thing an AAV does, but better. – Ernie Albus Apr 26 '23 at 12:14