A few questions:
1. How many layers of aquifer are in the area? Some have one, some have several, sometimes separated by layers that contain clay which keeps them separated. ("Got to keep em' separated"- Offspring).
2.How deep is the well? Sometimes, shallower wells will dry up in part or all.
3. How old is the well and equipment? Some well motors have a life expectancy of about 20 years or so, depending on amount of use. Not counting the well shaft which can get holes in it or partially collapse (hope that does not happen).
4. Are there any/many new buildings in the area? Housing developments? New industrial parks, factories, commercial buildings? All could overdraft the existing aquifer.
Some places, which have more than one layer of aquifers will recommend drilling the well deeper. I've seen wells 750 feet deep and some even more. I wouldn't want to pay the cost to drill 750 feet.
I'd say it's time to talk to some well drillers in your area. --24.180.xx.xx