I believe the pooling water is a problem just waiting to happen, compounded by the freezing and thawing of the snow and ice.What action can I take to recover funds paid to an un-coopertive contractor?

Usually there are lots of terms inside the existing open end note which deal with freezing of draws, repayment and default.  

It's very common although, as a bank, i'd switch them into my name if they were disconnected for non payment in order to ensure the pipes don't freeze and blow a line out.

The problem with burst pipes isn't that they freeze - it's that they UNFREEZE!  

Then ask if the structure is adequately insulated to prevent freezing of the plumbing in there. 

If you are in a cold climate though and you seal it in there then it's going to freeze and cause a lot more damage.

Recently as the stock market has been dropping, I watched my 401K account go from very good returns to heavy reductions (sometimes freezing).

Check yours and make sure there are no rent increase freezes in your area.

If not, your pipes are going to freeze.

@Xavier Aliche Sorry for the late response internet and phone service have been down with the freeze!