Slow draining Clothes Washer Drain

Question

My clothes washer drain backs up after about 10 seconds. If I wait for 15 seconds it will accept another 10 seconds of pumped water--but, it backs up again.

My kitchen & clothes washer are both connect to the same main drain line (~20 ft apart). I used an electric powered 3/8" drain snake to clean out that main line up to 75 ft. The kitchen drain drains perfectly, however, the clothes washer drain still hasn't improved.

I used a 5/16" drain snake on the clothes washer drain, however it would not go very far into the piping. I imagine it gets caught at the p-trap (which is inside the wall) and that is probably where the clog is.

I live in an older house & I don't want to use caustic drain cleaner chemicals in my old drain pipes to clear the clog. What is the next best DIY alternative for clearing out a drain pipe that has a p-trap in the wall or in the concrete floor (my 1st floor shower drain may soon need cleaning too)?

p.s.: There is NO clean-out access port in the plumbing for this drain.

Answer 1

Some washing machines have strong pumps that discharge lots of water quickly, overcoming the capacity of the drain standpipe. Yes, unless you can see it on the outside of the wall, there is a standpipe in the wall. You should consider increasing the diameter of the standpipe, thereby increasing the volume of water it can hold as the discharged water drains. I frequently use plastic pipe (PVC, ABS) and fittings for this.

This is not to say you don't need to also clear the drain, to do this you need a good quality 1/4" drum auger with a stiff cable. The good ones are expensive but will last a lifetime if used and maintained properly. I have had the same one since 1996 and have saved hundreds (thousands?) of $$ by clearing virtually every local clog myself (my neighbors' too).

There is some skill involved. Go to an actual plumbing shop to find a high quality auger and to get good advice on how to use it properly (or buy one and post another question about how to use it).

The good ones look like this:

Not like this: