Q:
I’m installing a new washing machine in my basement, as it’s the only viable place to put it in my small home. Unfortunately, the main waste line is roughly 6 ft. above the basement floor. Can a washing machine pump water that high? If it can’t and I have to install an ejector pump to lift the water to the waste line, how do I prevent soap suds from spilling out of the pump’s vent?
Jonathan Lavery, Ashland, OR
A:
Master plumber Mike Lombardi replies: Most washing machines are capable of pumping up to 8 ft. to reach an overhead drain, but check with the manufacturer to confirm the machine’s specs. For washing-machine drain connections in new construction, the IRC requires that 2-in. pipe be used for the trap, with a minimum 18-in.-high standpipe above the trap. Many jurisdictions allow 11⁄2-in. pipe for the trap and standpipe for a washing-machine drain, which I have seen work perfectly in hundreds of installations, especially with today’s water-conserving washers. Vent the trap by tying into the existing drain-waste-vent (DWV) system or, if that’s not possible, by adding an air-admittance valve. All washer drains require an air break where the drain hose enters the standpipe. That is, the hose is not sealed to the standpipe so that if the drain backs up, it will overflow onto the floor rather than into the washer. Backing up into the washer would contaminate it with sewage.
If soap suds overflow the ejector pump’s vent, it has been installed incorrectly. The vent should be tied to the house’s DWV system, making overflowing suds a nonissue.
