A laundry space saver is a plastic washer rough in box that mounts inside a stud wall and incorporates the water connections and drain into one handy location. I searched online for a link. See the second photo down from the top:

http://www.schlatter.org/Nneck%20House/rough...

You might want to consider getting a plumber to look at the situation. That way, you can ensure your supply lines are properly sized as well. You might also consider installing fiberglass or mineral wool sound insulation in the wall prior to closing it up as well. At least, on the kitchen side.

One rule that is certain is to never ever use orange&glo, oil soap, or other wood conditioners on a wood floor. I always use only warm water, hand washed with a wrung out rag, and dry the floor behind myself with a dry cloth. On tough spots, I use windex and rinse with a damp cloth. Otherwise, I would use what the manufacturer recommends. Typically, on prefinished floor, we will supply a Bona kit.

Tracy Boyle - it is possible that you have a buildup of wax or cleaner on your poly floor. Try handwashing several times and see how it helps. Otherwise, it might be possible to have a "screen and poly" coat, but not likely if you have a real buildup issue. Screening probably would not be aggressive enough.

SLS has the best advice. Hire a qualified professional to come out and track it down.

Also, it's best to not run food waste through the garbage disposer unless you really have to. It just adds to build up.