drain-waste-ventplumbingwashing-machine
I would like to install a washing machine in my basement, about 30 feet from the main waste stack. The stack is fully accessible and already has a capped 2" port about 8" above the concrete floor.
Can this be done? How do I look up the diameter and slope requirements? Where do I put a vent?
I would recommend not doing what you suggest, here's why:
A typical rough-in for a clothes washing machine is as show in the picture below and consists of the following:
Your discharge hose will fit inside the 2" pipe opening and will usually enter the pipe about 6" to 8". This connection is not water/air tight.
The size of the p-trap and the vertical section of pipe are to accommodate for the flow rate of the washing machine's discharge. The p-trap will create a restriction to the flow and the vertical pipe allows for some head water to buildup without putting any back pressure on the washing machine's internal pump.
A p-trap is a must as it will prevent sewer gas from entering your house. The vent is required to protect the water seal of the p-trap but can be replaced with an air admittance valve depending on local codes.
I would imagine that if your machine can pump that high it will be near its limit and without any room for a vertical section of pipe to discharge into you will have to make the connection sold which will put additional back pressure on to the machine's pump (even more due to the pipe size only being 1.5") which will shorten the life span of the pump.
Washers are supposed to drain into a vertical standpipe 18-30 inches in height above a trap. The trap arm must then be vented before waste water can be discharged into waste piping. I don't believe there are lesser requirements allowed for greywater discharge. By the time this all is installed, the washer must pump up to within 6 inches of the ceiling. How high the washer can pump is dependent on the model. Once this height is determined, you can calculate how high the machine must be to meet all requirements.
Best Answer
1/4" per foot of slope is generally considered the minimum slope, so as long as you have a bit over 7" to work with vertically, you should be able to slope the drain over 30' just fine. You'd set up your discharge p-trap, and then vent immediately after that...tying that back to the main vent stack. So you'll end up with two 30' feet runs of pipe (drain + vent).
Obviously, check with local plumbing codes for specifics.
This all assumes you have water hookups in that location. If not, then you'll have to get those over there as well.