Washing Machine

[allseason]

Can a wash. mach. drain be directly connected to a waste line with only a check valve, mounted horizontally, no trap. Here's what the owner's plumber states:

Looking at the picture of the washing machine drain connection you sent reminds us of your washing machine set up. Your drain connection is acceptable and was common in older homes where the piping conditions prevented the installation of a stand pipe. No trap is needed because the drain hose is connected directly to the drain piping of the house and no sewer gases can escape. There is a check valve on the drain connection and the check valve prevents water from backing up into the washing machine. The washing machine has been connected in this manner for many years and works fine. No repair or re-piping is needed.

Thanks, Chris

[Jim Baird]

"... no sewer gases can escape..." except thru the flexible? I thought check valves operated in pressure situations, not in drain ones. No mention here of drain pipe sizes.

[allseason]

I did some homework. Two things that are needed:

A trap & an air break.

My feeling is that a check valve only needs a bad gasket and it's methane city.

[Neal Lewis]

I report that condition as old style, outdated, no longer allowed, etc, etc. I've had a buyer move in and their plumber tell them it's a code violation.

[John Kogel]

Yes a trap and air gap, minimum.

I had an interesting installation in a basement. The sewer line was elevated about 5 feet up the exterior wall. Mr Handy extended the washer hose straight up to the floor joists, about 8 feet. Then he had a trap with about a 10" stand pipe and then ABS hung from the joists to the main stack at the sewer pipe.

I checked the manual for the appliance and the specs gave a max head of 9 feet. So I simply described it as unconventional and warned that the short standpipe might leak.

This other guy did this, basement laundry. He put the standpipe up to just short of the ceiling, with the trap at about 4 feet above the floor. Then he had a tee just above the trap, with the washer hose sealed with a pipe fitting and hose clamp to the tee. So the standpipe provides the air gap and it works.

I voiced my disapproval for CYA but thot it was workable.

[plummen]

Ive seen people build platforms to elevate washing washings in that situation.