Hi,
I have a clothes washer that backs up from time to time and it only has 2 feet of waste line before the trap. I just was looking at a post here that says at least 4 feet of pipe before the trap are needed. I have snaked everything out and the waste line can easily handle a garden hose discharge on full blast but can't seem to handle the larger amount of water coming out of the washing machine.

The mashing machine is in the kitchen under a window and 4 feet of pipe would put things in the middle of the window. If I relocated the supply lines and the waste line the most I could get might be about 3 to 3.5 feet of drain pipe before the trap (I'm on a slab).

Can I use larger diameter pipes to act as a ballast of sorts... ie. Instead of having 4 feet of 2 inch pipe have 3 feet of 3 inch pipe??

Does anyone have any suggestions. Apparently the original owners here had the same problem but failed to tell us about it when we asked. (I'm a homeowner looking for some advice). Thanks.

Hey Tommy,
Most washers are 36" from floor to flood rim,(lip). The stand pipe, (wasteline from trap) should terminate 1" over the flood rim of the washer. The average length of a stand pipe is between 3 and 4 feet. Increase yours as much as you can. I had the same problem at my house the washer pump discharged with so much force that it sometimes backed up. I cured it by attaching a 2 X 1 1/2" compression fitting on top of the stand pipe and making a water tight connection between the hose and stand pipe. Your trap and stand pipe are 2" aren't they? If your trap and standpipe's 1 1/2" simply purchase a 1 1/2 female X 1 1/2" compression fitting and install that. Good luck, Tom

Thanks speedball,

The unit is in the kitchen and there is a drip pan/valve box (if that's what you call it) for the washer supply and drain lines. I don't know if the compression fittings would look good or work for me there. I was thinking of using fome silicon around the connection since it is only a small amount of water.

Do you worry about building up pressure in that washing machine drain line. Mine is plastic and does not look like it would handle pressure well.

Before I installed the compression fitting I caulked the hose in with a old pair of socks. Since you don't have a major backup when the pump discharges, I don't think you'll get enough back pressure to damage the existing hose. Do the foam thing! Sounds like a winner. Best of luck, Tom