Hello everyone!
This is my first time on this site - I am a female home owner with a not-so -handy husband. So , I always try all avenues to learn about my home and try to fix it myself when I can.

My problem is my kitchen double sink filling with nasty water when I run my dishwasher. There is no disposal in the sink. Water does not seem to back up during regular sink use
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My home is an older home in the south (circa 1950) and the dishwasher is about 8 years old. This is a recent problem (3 weeks).
Any help would be helpful, before I start tearing apart the trap and getting messy.
Thanks in advance!

Sounds like you have a partial blockage in the drain line in the wall. Let me explain. The water from the dishwasher comes into the sinks drainage system under pressure and great volume. Your sink drains a little under gravity. The partial clog will let the sink water drain through but will back up on the heavier discharge from the DW pump. The answer is to open up the trap and send a snake up into the wall. You'll hit a elbo about 8 inches in but once past that you only have 6 feet more of cable to run in. Flush it our afterwards with hot water. Good luck, Tom