Our home is about 6 years old with the washing machine on the second floor. Just lately, the drain pipe backs up a little water, but mostly bubbles. I've tried to snake the pipe but I can only get four feet in before I hit a bend that the snake gets stuck on. I don't think this is the blockage because when I turn the snake I can tell I'm just hitting pipe and there is no blockage residue on the end of the snake. About two feet from the drain pipe there is a capped pipe than I'm assuming leads to the vent as well. I've snaked this but don't seem to hit any blockage.

When it starts to backup, I'll pull the drain hose out a bit to see what's going on and it almost looks like there is pressure pushing the bubbles out, then eventually they slide down the pipe very slowly.

When I snaked from the roof it felt like I hit "something" twice, but it was very minor both times and then I ran out of snake line (25 feet).

I've tried running water from the washing machine water lines down the drain pipe with as much pressure as I could to see if it would eventually backup and it never does.

But when I wash a load, even with minimal soap, during the final rise, bubbles start overflowing.

I'm stumped. Any help or advice would be greatly appreciated.

Rich

Some soaps create so much suds that they can fill the pipe full of suds and even with water rushing through the pipe it will make the suds overflow the stand pipe. Try a couple of low sudsing detergent