Constant active water pump

[Truman]

My Water pump is constantly whirring, Tap seems to be just fine. Anybody come across this issue before?

 

[Truman]

I've disconnected the pump itself as my batteries were dead. Could this be a tap issue?

 

[ArunAlec]

My guess would be that the contacts of the micro switch in the tap have arced and welded themselves together.
I and others have made a modification by adding a relay to the tap circuit to reduce the current through the tap.

 

[scottk]

If you have a shower, it can also be the switch on that.