Question
Our drainfield area was reseeded after we purchased our home.  The grass grew nicely but in just a few months the yard looked bare again.  The yard does appear to have tunnels & the soil is very soft & mushy.  I checked the soil with my hands.  It is very easy to dig (no clay here) & I checked for septic odor or slug on the surface, nothing found.  So all I can conclude is voles or moles eating up the new grass & making the ground so soft it's hard to mow it.  Are my conclusions plausible?  Thanks.

Answer
Hi Katie, could be moles.  Their digging lifts the grass which allows the roots to dry out.  Normally, a thorough watering will settle the grass into place so there is minimal damage.  You may need to invest in a roller if the problem is sever, but regardless pick up your watering so it will not dry out.
Check your pH, needs to be 6.5, fertilize at the appropriate time for the type grass you have and you might try a repellent to run them to your neighbors house.  Jim