My washing machine rinse water backs up into my double kitchen sink and my wonderful plumber is stumped. I'm only able to wash a mini load (which fills up both sinks) as a medium or large load causes my kitchen sinks to overflow. It's been doing this for over a year now and I'm tired of living with it.

My plumber has worked all week snaking lines and blowing them out. He cut into the wall behind my washer and did some stuff (I'm plumbing-challenged so I don't know everything he's done). He also brought his son-in-law out to try to fix it and neither of them have been able to stop the water from backing up.

The water that backs up into the sink used to be extremely dirty and black, it almost looked like oil. But after all the work they've done the water is now fairly clear, but it leaves a thick sediment in my sink, not only dirt but also trashy looking stuff. I scoop out about 3 tablespoons of stuff and throw in the trash. Because of this sediment, they think it's possible that the drain line under my concrete floor is too small to accommodate the rushing water and that a connection has probably come loose under the concrete. My house is 30 years old and my washer is about 12 years old. He said the drain lines in older houses were not big enough to accommodate newer washers.

My plumber said we may have to reroute the drain line out the front brick wall of my house, lay pipe across the front of my yard (which means digging across my concrete walk), then down my side yard to connect to the line in my back yard. He said he would only do this as a last resort and wants to think about it for the next week and talk to some other plumbers to see if they have any better ideas.

Do you have any suggestions I could pass on to him?