Have a well that serves entire house water use, including watering a garden and other plants around house. Recently, while using the shower, the water pressure went extremely low to the point where there wasn't enough pressure to trigger the instant on water heater -- finished with a cold shower. Checked the water pressure at the pressure tank and observed max of 20PSI. Thought this was a pressure switch problem. Got a new one and installed it and problem continues -- pressure not getting better than 20PSI. Any went to the well and checked the spicket there to make sure there was no leak. No leaks there but the pressure at the spicket was also low. While at the well, had another person control the well pump from the house fuse box. Turned pump off/on from the fuse box and could hear the switch going on and off at the controller box at well. Also heard the pump humming when turned on. Notice the water from the well spicket would start strong and plentiful for about 10 seconds and gradually go down to almost unusable. Left pump turned off until needed and now controlling from fuse box until I can get the original pump installer to fit me in his schedule. Meanwhile, cold water quicik showers is the only way here. Could the problem be the pump or the water line from the pump developing a hole or breakage ?