Not to pump one of the owners of this site but we used Mike Otto. We have a number of soils(sand, black soil, clay, rock, red dirt)so it was very important to us that we get the right location. My father actually built the lake. I didn't see a reason to because we already had a lake. Boy was I wrong. Mike actually had dad move the dam location and make it a smaller lake. This cost Mike some $$$ but really made sure we got a lake that was going to hold. I don't think anyone can absolutely guarantee you that your lake will hold water. Drilling test holes is an absolute must. It will tell you the likelyhood of success. I think all earthen dams are going to leak to some degree. If you do the soil in the hand test you may find when you start digging that you have no clay 5 ft down. I would find the professional dirt mover and let him see the land before you buy and get permission to drill some test holes. If the lake is the defining point of buying the land make sure you've got it right before buying. Please let me make sure and say that I am no expert. I'm just regurgitating what we have learned from people like Mike Otto & Bob Lusk.
They are not perfect either but it increases your odds of success when you have someone that knows what they are doing and is not in it to make a fast buck and has been doing it a number of years. Just my thoughts.
