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Toilet installation

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Posted 2013-12-04T21:49:38+0000  by georges georges
You don't actually bend the pipe down, georges

Slope is not the angle of the flange, but rather the slight incline required in the longer run of drain pipe between the house and the sewer.

When Mike said, the standard is 1/8-inch to 1/2-inch per foot of drain pipe, he means the long drain pipe between the house and sewer will be very slightly higher at the house than where it connects to the sewer ... the downward slope assisting movement of waste.

Over a fifty-foot run, that pipe would be only two-feet lower at the sewer than it originates at the house.

You also want to be certain the pipe does not have a low spot, but has continuous gradual slope.

Low spots can trap both air and waste causing backups and other problems in the future.

Best Answer

Posted 2015-11-05T22:02:17+0000  by Pat_HD_ATL

Hi Georges,


Code requires slight slop to the drain line, however, only from the p-trap on down the line. So any normal fitting such as a 30,45,60 or 90 will work.


You must have a p-trap to prevent sewer gas from entering the home.


Check your local building code for specifics.



Posted 2013-12-05T18:58:33+0000  by Mike_HD_OC

Why would I use a p-trap in a toilet waste line? 

Posted 2013-12-05T21:03:43+0000  by georges

Hi Georges,


My error, I was thinking of a previous question about sinks when I answered your question.


A p-trap is not required, the line needs a slight slope when installed, you can use standard fittings, your local building code will specify the slope required.


The standard slope is 1/8"- 1/2" per foot depending on local code, most plumbers try to make it at least 1/4 inch.


Contact your city building department for the exact specifications required in your area. If the job is to be inspected the 

local code must be followed.



Posted 2013-12-05T23:39:59+0000  by Mike_HD_OC

This brings us back to my original question: what standard fittings do I use to create such a shallow slope?  Thanks for following up. 

Posted 2013-12-06T19:50:27+0000  by georges
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