RF Martin
New Mexico
As you can see in the photo, in a bath remodel, our contractor has installed a new shower drain at a new shower stall location so that it drains directly into a new passing toilet drain line without a p-trap in the shower drain line portion. He says there is a baffle of some kind in the reducer portion of the 4" toilet line wye fitting that "prevents water and waste from backing up into the shower drain". My Home Depot plumbing guys were unaware of such a fitting other than backflow valve for like a sump pump set up. Contractor says there are different kinds of "wye" fittings on the market and his has the baffle. However when we flush the toilet...down in the shower drain we still hear the water loudly rushing by and air comes up the shower drain. When the wind blows we can hear and feel it up the drain. Contractor says there was no room to put a standard p-trap and that this installation is legal, meets code and is accepted practice in plumbing. He says the loud rushing water noise in the shower is just a normal byproduct of this kind of installation. The toilet drain line continues to the vertical vent line which is the only vent line for the new shower/toilet drain system. The new toilet was relocated to a position about 10 feet away from the vent, using a 4" drain line. Here on your forum and others it seems a p-trap should have been installed on the shower drain...but I do see occasional references to alternate practices. We are at a loss whether we need to pursue repair of this before we accept it. The project is still underway, although this junction is now sealed under concrete and tile. Do we need to require that it be dug up and changed? Is it actually OK and we just need to ignore the noise? Do we get one of those SureSeal waterless drain trap sealers and plug it in?
Thank you
Thank you
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