Can you attach more than one drains to a single j-trap? I want to move my washer from inside the house to the garage. The garage wall has got the master bathroom on the other side so I want to install a new washer drain line and hock it up to the j-trap from the bathroom sink. Can this be done? Thanks for any help

Sorry 50, you definitely cannot connect your washing machine into the lavatory sink j-trap (actually called a p-trap, I believe).

You can connect into the drain pipe that feeds the lavatory... as long as you vent the washing machine. If you do not vent washer drain, when WM drains it will siphon the p-trap at the sink and cause unhealthy conditions and bad odors in bathroom. NOTE ALSO, that you cannot connect into sink drain line if the sink drain/vent act as a wet vent for the toilet... How can you tell.. Well, IF SINK DRAIN IN WALL IS 2 INCH WASTE AND VENT, PROBABLY A WET VENT AND THEN CANNOT DRAIN WASHER INTO THAT.

There are quite a few codes associated with washer drains... such as distance trap to vent... cleanouts... even the length of pipe coming out of the p-trap itself (between 18 and 36 inches depending on which state you are in... most on this site quote 30 inches tall as good rule of thumb).

AND JUST SO YOU KNOW... most experienced plumbers prefer to see a washer drained into a 2 inch pipe (with 1.5 inch vent)... so would really like you to find a 2" pipe to connect into...but if not possible, like I said you can go with 1.5".

I have quoted you information that is code required in MASSACHUSETTS and is acceptable in many places throughout the country. BUT please note that each state has its own requirements, and further, that each city inspector has his interpretation of those codes. SO, POINT IS TO CHECK FIRST WITH LOCAL PLUMBING INSPECTOR AND SEE WHAT HE THINKS!!

I know that was a lot of info... complicated question... believe it or not... ;)

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