I've got a very small sinkhole that has developed between my driveway and my water meter vault/box. The hole is about 20 inches deep and has actually eroded the soil deep enough that it goes underneath the side of the meter box.
I'd like to fill it back in, but want to be careful that the fix is relatively permanent and not papering over some deeper issue, or risk having the hole spread under the driveway pad and having that sink, or under the meter and having the service line flex and start leaking.
The hole and the meter vault are both dry, so I don't suspect a leak from the service line or on the house side. Water bills are normal.
I'm thinking that water runs off the driveway through the score line, soaks in here since it can run into the pit made by the drain vault, and carries away soil as it does so. To fix it, I plan to fill the void with drainage rock and then cover it with permeable fabric and new sod. My thinking is that this will let the water flow across the rock and soak into the utility pit (it's not pooling during storms, so it appears to be low enough volume that it's absorbed and isn't filling up the utility box) without carrying away soil.
Is this likely to cause future problems, like the service line sinking and leaking? If so, what is the right fix? Should this utility box go deeper into the ground?
Additional info, in case it helps: there's a sprinkler system in the yard, but doesn't have any lines that run through here. I also never use it, so it's not like it's adding a lot of water to the yard that is contributing to the problem.