Minimum height of sink outflow pipe relative to p-trap outflow pipe

Old 09-19-21, 11:35 AM
wubbzy's Avatar
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Minimum height of sink outflow pipe relative to p-trap outflow pipe

I want to replace my old top-mount sink with an undermount sink, which would result in the outflow pipe from the garbage disposal being only 1.25 inches above the outflow of the P-trap. I've read that the p-trap should be no more than 24" below the outflow from the garbage disposal, but there is no minimum distance. Will water have trouble flowing out of the garbage disposal if the p-trap outflow is only 1.25" below the garbage disposal outflow? Thank you.

Old 09-19-21, 03:15 PM
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I had a similar problem. I increased the length of the pipe coming down from the disposer.
This results in a deeper than normal trap retention area.
I allow more flushing after using disposer to make sure trap is clean.

I have an old house and there was no way to mess with the iron pipe in the wall.
One day I may run a new drain line down. The hard part is picking up the vent.
wubbzy voted this post useful.

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