The Board was informed by the contractor who maintains the well and generator that the well pressure tank is failing. They said this causes significant water hammer when the pressure is low in the air portion of the bladder. They’ve been adding air each visit, but it’s failing to the point that, since they’re not here but every two weeks or so, the air pressure is gone by the time they get back. The water hammer is hard on the pumps.
The pressure tank will be replaced soon. [EDIT: The high-pressure switches will also be replaced, as one has failed and the other one is not looking good. This is likely affecting water pressure.]