If you pump water into your home from a rainwater tank, then you rely on the pumping system to give you water when you need it. If your pump stops working normally, then it might need a repair. Or, you might need to replace it.
Before you decide what to do, try to work out what has gone wrong. Why do these water tank pumps stop working?
If you feed your rainwater into your toilets or washing machine, then internal leaks in your general plumbing system can affect how well your water pump works. Open taps or valves can have the same effect.
Here, your pump struggles to work because water is discharging from your tank unusually. The leak or open tap/valve affects the pump's pressure measurement system. So, the pump might cycle on and off all the time. Or, it might run constantly. If the pump itself seems to be working, then a leak or open connection might be the problem.
2. Switching Device Problems
Your tank's pump might have a switching device that balances its supply with your mains water. If your rainwater tank doesn't contain enough water to meet your household needs, then the system switches to using mains water until the tank tops up. Sometimes, these switches develop problems. They might get stuck in one position or completely break. Sometimes, they have the wrong settings which mean that they can't deliver the pressure you need.
A problematic switch can make a pump cycle on and off all the time. Sometimes, the pump will start working when there is enough water in the tank but will then suddenly cut out and stop working. If the switch isn't set right, then the pump might not deliver the water you need. For example, if the switch is set at a low flow rate, then you won't get the right water pressure.
Your tank's water pump needs a clear system to work correctly. If you have a blockage in this system, then you might notice that your pump struggles to deliver. For example, filters and strainers can clog up. If this happens, then water can't flow through them at the optimum rate. Your pump won't be able to deliver the water you need at the right pressure.
Problematic, failing or broken water tank pumps need expert diagnosis and repairs. To sort out your water tank pump, contact your plumber.