maintenance?

Background : I have a old (main house 100 years w/ several additions) 3200 sq ft house that has  an additional 1500 sq ft space for a indoor pool (16x32x5). I am redoing the ductwork for the main house and hopefully putting in a geo unit for the pool along w/ a humidification system. I have estimates for a 5 ton geo unit for the house and one for the pool room (to heat air and water). I have to go vertical w/ the systems so I need 10 bores. If I go w/ a traditional system that means about 28,000 for the pipes. This piping is cheapter for a dx system but the system costs more so there really isn't a savings. I am looking at possibly diong one or both of the systesm as open loop (I have a pond and a large ditch to which I can drain the water), but I am concerned with the maintaince of such a system. I also would mind using a return well for one of the systems. I am concerened that the open loop system will have way too much maintenance even though it could save me a hugh amount of money. My contractor says that I need good water. What does "good" water mean?