Plumber advises to keep air inlet when removing house trap

D107

He advised that if replacing old house trap with straight pipe and cleanout, keeping the air inlet vent is advisable since it lets plumbing system breathe. Others have said that once trap is gone, the air inlet is no longer needed.

Robertw

The fresh air vent on a house trap satisfies the plumbing code that every trap must have a vent. With removal of the house trap the home plumbing will be vented through the stack vent through the roof and possibly other fixture vents going thru the roof as well.

House traps are no longer required in most areas.

jumper

What is wrong with extra vents? I like inverted U s to prevent stuff falling into drain line.

Mad Dog_2

Nothing wrong with leaving it. Mad Dog

Intplm.

When it comes right down to it, if you leave the vent installed it will be an extra vent. There's no harm in leaving it there.

Danny Scully

I’d have to disagree. You now how the entire street (and more) venting out of the side of your house. It’s no longer a fresh air INLET, it’s just allowing sewer gases to expel at an unacceptable height off the ground. With the house trap installed, the fresh air INLET is in front of the trap, not behind it.

D107

@Danny Scully Very good point! One would think it would be against plumbing code to leave the air inlet in if there's no trap. One wonders how often plumbers find such a setup.

Mad Dog_2

Good point Grasshopper, but it's no worse than a street manhole cover. I'm keep my house trap and my Fresh Air Inlet.....Mad Dog

jumper

Real stench comes when house trap leaks and there's no vent.