Rough plumbing for Washer.....Do I have to have a sink?

Question

Hi,
I am adding some plumbing for a washer machine in my addition. My question has to do with the drainage of the washer. Do I have to have a sink for the water to drain? Do I need a P trap? Can it drain directly into the vent? or should it be a seperate pipe? I guess my question is basically what would be the best way to set it up??

Thanks for your time,
pb4sc

Answer 1

The most common setup for a washer drain is a 1 1/2" pipe, either coming up from the floor or out from a wall, depending on where your pipes are, a short distance before installing a "P" or "S" trap. The "P" trap would go into a wall, the "S" trap through the floor. I suggest a screw together setup for the trap, as opposed to the glue together elbows, (it makes it much easier to dissassemble in the future to remove debris that may build up there, and yes they are available). Then come up with the pipe to approx. the height of the back of the console of the wash machine. Your machine drain hose should have come with a hook end on it, which is intended to be placed into the top of the pipe. The water from a wash machine pump needs to go up to at least the height of the lid level of the machine before going into the drain for some reason known only to the manufacturers. ( I used to sell GE stuff and that's what they told us.) That's about it. I've installed lots of washer drains in this manner and as long as the system is vented properly it works great.. Good luck.

Answer 2

Corky had a good explanation how to do it.

The reason why the drain pipe must be at the height of the top of washing machine tub is to make sure the drain hose will not siphon out any water in the tub during wash or rinse cycles, or any water from the P trap back into the wash tub.

Most vertical tub machines have an impeller pump at the bottom of the tub which pushes drain water out when the tub is spinning at high speed. For higher reliability and to keep costs down, the mfrs usually don't put a check valve after the pump. Hence, the anti-siphon design for the drain hose and standpipe.

Answer 3

Washing machines must drain into a 2" pipe, 30" tall with a P-trap. A 1 1/2" vent through the roof must be installed downstream of the P-trap.

Answer 4

If you have the room a sink would be nice.....If not much room An inch and 1/2 to two inch drain is plenty for a washer..And yes,the vent pipe can be connected to the P trap.

Answer 5

No sink, stand pipe minimum 30" above trap, 1 1/2" pipe. Drain line must be vented within 36" of the trap.
Two hose cocks, one blue handle, one red. Or buy the specialty dual valve for washer hookups.
Yes, you need a trap. I'd put 18" air risers above water valves to eliminate banging when electric washer valves shut.

Answer 6

They make "pocket drains" that fit inside the wall for mounting flush with the wall for just that purpose.

Answer 7

no sink...just a drain and p-trap to keep gases locked