2nd floor laundry room drain trap is fed from pipe going up to a shower....i have water spraying out of the laundry room drain everytime i turn on the shower...it's been working fine for 10 years and now does this. HELP
It's clogged. Hire a plumber to snake it, or buy a snake and do it yourself. A simple drill mounted snake (about $10-$15) should do it. If you've never done it before watch some youtube videos explaining how first.
It's probably full of hair. Once you clear it make a point of periodically (every 6 months or so) taking off the drain cover in the shower and removing the built up hair.
The "Zip It Drain Cleaning Tool" works very well for removing hair. (And despite what they say it's not a one time use tool - they just wish you would think so.)
When snaking your goal is catching things and pulling them back up to you, not drilling a hole in the clog. If the snake doesn't turn easily immediately stop the drill - you don't want to overstress the snake and break it in the line. Never EVER run the drill backwards with a snake - not even when removing the snake from the line!