I'm doing a kitchen remodeling project. I now have a deeper sink basin with a garbage disposal on my double sink, which means I have to lower the p trap by about 6" compared to the previous installation to. My question is.... "What is the maximum permissible vertical (head) separation between the standpipe and the p trap ?"
- The standpipe vertical height above the floor is about 20"
- The disposal discharge height is about 2" above the standpipe
- The bottom of the p-trap is roughly 10" below the standpipe and 3" above the floor of the cabinet, and drains both sinks.

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Originally Posted by ;

The bottom of the p-trap is roughly 10" below the standpipe and 3" above the floor of the cabinet

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Sorry! But your going to hafta pay for those deeper tubs. You can't make water run uphill.
The wall will have top be opened up to the vent stack and the sanitary tee and sink arm lowered to pick up the trap. Either that or go back to your old sink. Good luck, Tom

Tom,
Discharge from the disposal is 2" above the standpipe, so both sinks and disposal should drain. Are you saying that I need more than 2" vertical separation?

Tim

Sorry,

I may have confused terminology. Got it all back together and it works fine. Thanks for your comment.

Tim

Hi:

I just went through a similar issue. I installed a new 10" deep sink vs: my old 7" sink. Also, I have an undermount now which makes my new sink 11 1/4" from the top of the counter top. Anyhow, the drain line coming out of the wall is somewhat too high so when I set up my new garbage disposal, I had to reverse my P trap to make up for the high difference. It works great and yes, the water has to go up hill a few inches, but there is no issues. It workd perfectly.

We thank you both for the updates. Happy you found your own solutions. If we can ever help in the future just ask. Good luck, Tom