We have well water with a submersible pump. Water also shuts off when using washing machine, etc.

When you say "
Water shuts off when using washing machine, etc.
Are you saying the pump shuts of and the water stops or the pump keeps running but you get no flow?
Let me know, Tom

SB has given you good advice. If you are not sure if the pump is on or not, pull the grey cover off the switch and see if the points are closed during the time when you have no water. If they are closed, then the switch is doing its job and the problem is probably centered around your pump. If the points are NOT closed, then there is a problem with the switch.