S and P traps

Dumb question.
Why is an S trap not allowed under a sink, yet the trap molded into a toliet is basically an S trap?
Just curious here…

The internal trap in a toilet is a P-trap.

The upstream area of the trap way holds water when the bowl is full.



Well well Mr Graphic,very nice.:slight_smile:

So…a p trap turned on its side and emptying down and not to the wall is acceptable?

Sure, the arm length needs to be 2 x’s the trap diameter, though.

Like this?

The things we find. That’s an original for me.

That is AWESOME! :mrgreen:

Toilets are the only allowed S trap. A plumber might know better, but I think it is because of the way toilets fill, a small amount of water is diverted through the rim to fill the toilet trap as the tank fills up.

I spent 3 yrears trying to documenting an “s-trap” failure with thermal imaging.

No luck yet.

You got one, “show me”…