septic field creating uneven lawn surface
 

My septic field is about 12 years old, clay based soils. slight slope in my backyard. There is a depression wherever the pipes are and this is creating an uneven lawn surface. I was wondering if I could fill in the depressions with a sandy soil mix? The depressions are about 6 inches deep or less over the field lines.

Yes you could fill the areas in, would not be a problem. This is caused by every thing settling since the drain field was put in.