Bob wrote:
What is a percolation test?

It's a test usually done for people who are going to install septic
systems, to see how close to the ground the water table lies.

I've read the entire thread (since the subject is so close to my
heart). I agree with the poster who said not to worry if the builder
hasn't announced or acted as if the floor is ready to go on, or the
drain work is complete. At one point in my mother's construction, when
proper drainage still was possible (the foundation just having been
poured), the first of interminable thunderstorms swept through, and the
"room" took on at least six inches of water. I didn't have to call the
builder to know there was no reason to worry about it--THEN.

But in my case the builder CONTINUED to act this way. If yours
conducts himself in such a way to suggest your extremely valid concerns
are negligeable, then I say, Heck, be the QUEEN of Nervous Nellies.