I wish I could help you but I really don't know and apparently no one else does either.....maybe try a couple of the other forums..

I may be a tad late since I normally visit the MSN groups, but your problem is not unusual for those living in a high water table state or location. Septic tanks are a curse for natural springs, which you want to drink from instead. Apparently you don't have the option of city water and sewer treatment so you are forced to use a "leak tank system". If it is possible, get with the water department in the nearest city and see if they have mapped your natural spring, so you can figure out where it runs and get as far from it as possible. Of course if your soil is heavy in clay, you will never have a very good drainage spot anyway.

In the case of heavy clay soils it takes a ton of rock and pebbles made into a drainage field away from any natural spring or home to begin to solve the problem. The US Army cooks, engineers, and other land based military "service providers" are required to know how to create a proper drainage field, depending on how much liquid waste they expect to generate by a "head (troop) count". Ths also means the soil type has to be inspected and tested for "drainage" ability. A camp is not expected to remain in the same place all that long, normally counted in weeks, but tending towards months in modern times. Because camps are moving towards months too close to a year in modern warfare, more permanent solutions are required, which means a waste treatment facility.

I doubt you have the time and coins for such an adventure, or you would not be asking these questions here, but would have hired someone by now to do all of this for you. In any case, there is one draw back to having the city planners in the drinking water generation department tell you where your natural spring runs under your place. During drought years as the city grows, they will figure out some way to take the water and prevent you from tapping in. The idea is to get you on city water supply, and manage your natural resource. It is a necessary evil in these days of clean water needs by cities growing too fast, and now a pattern world wide. The earth is becoming more and more dry, so ...

You may wish to try a post of the "The Home Site". Its linked at the forum index page.
Mike