Re: toilet drain line sizes
Posted by hj on December 27, 2002 at 22:01:07:
In response to Re: toilet drain line sizes
Not necessarily. Hydraulically speaking the small line will have a greater flow rate so it should be better at not plugging up. But if either size is installed properly, it will give the same overall performance in your situation. Most new plumbing is installed using 3" until a fourth toilet is introduced and then the line is increased to 4".

: I am installing a new toilet into an existing 4" main line and am finding no information about wether a 3" or 4" drain from toilet to main is preferable. Pipes are in basement so there is plenty of room, extra cost of fittings is minimal, is there some inherent reason that one size would be better than the other? My instinct tells me go bigger, is this correct? Thanks for the help.

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