There is a water backup coming through the sink, both sides, and under the dishwasher. I would assume there is a back-up somewhere in the line. Can I use Draino to fix it?

Thanks.

If we move you to plumbing you will get more responses. Don't use the Draino, you can try to plunge but I'd start by removing the trap under the sink. You'll need a bucket to catch the trap water and any other backing up. Rod into the drain pipe coming out of the wall.

If we move you to plumbing you will get more responses. Don't use the Draino, you can try to plunge but I'd start by removing the trap under the sink. You'll need a bucket to catch the trap water and any other backing up. Rod into the drain pipe coming out of the wall.

Why not the Draino? Home Depot told me to use it. Too late on that one.

Ok, the plunger just sent all the water again back under the dishwasher and on the floor. Any help.

First of all stop using what ever is above the level of the sink.

under the dishwasher

Could you clarify that or expand on it please.

Came out from under the dishwasher and onto the floor. I am hesitant to pull the dishwasher out.

Look under sink and see if water is (or has) coming out of pipes there.

Nope. Nothing coming out of the pipes under the sink.

Let's talk for minute

water backup coming through the sink

Does that mean that you have water backed up in the sink and won't drain or does it
Mean that water is coming up into the sink from the drain?

You have a double sink. Do you have a disposal?
Do you have an air gap for dishwasher?

Water is coming up from the drain and we have a disposal. I don't know what an air gap is.

Ok, as previously advised ,I would stop using anything above the level of the sink. Appearently you have a blockage some where in a main line and water has backed up to the level of the sink.

An air gap is a chome (usually) knob looking thing that sits on the back rim of you sink and prevents water from the sink getting into you dishwasher.

Look under sink again, does dishwasher drain hose hook to disposal or does it hook to that knob on back of sink and then to disposal.
Look in dishwasher to see if you have sewage in dishwasher.

Do you live in a private home, an apartment, condo?

Harold and I are both having difficulty picturing what you have but you asked 2 questions. Why not Draino, well is screws up your disposal, leaves acid in your pipes if the blockage isn't cleared. Home Depot said to use it, well they sell it and they aren't plumbers. A friend of mine works at HD, he has me do his plumbing repairs.

Air gap, if you have one, is a small can shaped thing sitting on top of your counter next to the sink. You may nopt have a gap if your installer decided to use a high loop in the drain hose before connecting to your disposal. All I can guess is your drain is blocked and the washer is overflowing its tub because the water in the sink has no place to go. I still recommend removing the trap and rodding the drain pipe going into the wall.