Do you know how deep your current well is? Have you explored it? We have a hand dug stone-walled well, which fills from the water table. In our first summer it ran dry - ten French visitors helpfully washing up under running water, and flushing the loo after every child's tiny tinkle will do that
Anyway Mr F and friends went down inside the well (with full safety equipment and precautions) and found it was quite silted up. They cleared out the silt, replaced the pump, let the water settle and fitted a filter and UV light at the collection tank in the attic. That was enough to sort the problem and we can even run the granny flat from it too. We don't have a dish washer (no mains water pressure anyway) and we are careful about flushing too much in a drought.
At the time I did investigate getting a borehole, but the prices quoted would have bought us a new smallholding! Same with being connected to the Mains.
We don't use this water for the smallholding, livestock, veg etc, that is all collected in giant black barrels from every roof around the place. Drinkers are placed in every field and fill by gravity from our highest spot (the water will run uphill too) and we pump it up there using an electric pump. In the winter we take warm water out to the livestock in buckets from the house.
This system has worked for 23 years for us.