[upthesaukee]

If you have your cover uncovered, it is undoubtably fairly close to the house. With a tape measure, take a measurement from one corner or prominent feature of the house to the cover. Take another measurement from another corner to the cover. Draw a simple diagram of that side of the house including those two start points and the cover. Record the measurements. I have these measurements recorded on a sheet of paper in our mud room, behind the door. In five years, when it is time to have the tank pumped, I will simply grab my tape measure, go from one corner of the house with the one measurement and scratch an arc in the ground near where the other measurement should intersect. Then do the other measurement and scratch the arc...the intersection of the two arcs is the cover, and ten minutes of digging has the cover exposed.