We had our finished basement flood with some severe rain not too long ago. We hired a contractor to trench out the basement so they could water proof it. Upon doing this they came across a tank and are afraid to remove it because they don't know what it is. They opened the lid and it was filled with water, and either sand or concrete (I haven't poked it with a stick yet). Has anyone seen this type of tank before? http://mcaf.ee/2s1en
My guess is it's either an old abandoned oil tank, septic system, or dry well. What I don't understand is if it is a dry well why would you put it a foot from the back of the house?
Any ideas would be great and much appreciated.