Hello,
We have just been notified by our local water company, that are usage is way up and they came out to check the meter and said that they detect water running, although no one was even home to be using it. I have noticed that the sump pump is running a lot, but there are no visible signs of water anywhere in the yard or toilets running, leaky faucets. Any suggestions?

Yes your underground pipe has broken more that likely. This can be a hidden leak since all the water is going to the sump pump. Sorry to be the barrer of very expensive bad news.

How old are the pipes and what material are they made of? Copper? Plastic? Or galvanized? Let's see if we can pinpoint the leak. Close the house shut off and and don't turn on any fixtures. Now go out to the meter. If the little pointer's still turning the break's in the service line between the meter and the house. If it's not turning then you have a open line in the house that's running water and costing you money. Shut the water off at the meter shut off valve, or house shut off, so it doesn't run all night and call a plumber in the morning Good luck, Tom.