Our Laundry Sink Overflows when using the kitchen sink.. with really nasty stuff flowing back out.

As a result, sometimes when we're doing the laundry the water drains out very slowly, and we can never do the dishes and laundry at the same time. I'm worried that this may eventually become a bigger problem.. what's the best thing to do? We use draino periodically, but I don't think that is solving the problem, it just seems like a short term solution.

Thanks!

I am no fan of pouring harsh chemicals down your drainage system. The only time they seem to work is in TV commercials. Having said that the only sure way to clear a clogged drain is to snake it out.
You have a partial blockage downstream from the laundry tray. You may snake from one of two places. The kitchen roof vent or the laundry tray roof vent. Put out enough cable to reach the base and about 20 feet more. Test by cycling the washer. Good luck, Tom

Thank you very much speedball.

Can you point me to any posts here that detail the best way to snake? Do I need to rent a sewer machine for this? How much does this cost if I hire a plumber?

Thanks.

Another stupid question.. are the kitchen roof vent or the laundry tray roof vent.. up on the roof?

Both are roof vents. The kitchen vent's located above the sink on the roof. Regards, Tom

thank you very much speedball.

can you point me to any posts here that detail the best way to snake? Do i need to rent a sewer machine for this? How much does this cost if i hire a plumber?

thanks.
This is how you would snak the drain. Go up on the roof and locate the sink or washer vent. Put out enough cable to reach the base and about 20 feet more. Test by cycling the washer. You will need to rent a sewer machine from your local Rent-All. I have no idea what plumbers charge in your area. Good luck, Tom