My rainwater pump turns on by itself
A rainwater pump should only run when someone flushes a toilet, uses the washing machine or turns on a garden tap. If you hear it kick in at random times, in the middle of the night, or short bursts every few minutes, something is letting the pressure drop in the pipes. It wastes power, wears out the pump and often points to a leak. Here's what causes it and how it's fixed.
Why a pump turns on by itself
A leak somewhere
A running toilet, a dripping garden tap or a hidden leak in the pipes lets pressure fall, so the pump switches on to top it up. A toilet that keeps refilling is the most common culprit.
Faulty check valve
The non-return valve stops water draining back into the tank when the pump stops. When it wears or catches grit, pressure leaks back and the pump keeps restarting.
Worn pressure switch or controller
The switch or electronic controller that tells the pump when to run can wear out or get clogged with sediment, making it start for no reason.
Pressure tank problems
Some pumps have a small pressure vessel that cushions the system. If it loses its air charge, the pump cycles on and off rapidly.
Sludge from the tank
Sediment drawn up from the bottom of a tank that hasn't been cleaned clogs valves and switches. See our rainwater tank maintenance page.
Quick checks
- Put food colouring in each toilet cistern. Colour in the bowl after 15 minutes without flushing means that toilet is leaking.
- Walk around and check garden taps, hoses and irrigation for drips.
- Note how often the pump starts with nothing running. Short bursts every few minutes usually mean a check valve or pressure tank problem.
How we fix it
We test the system with everything off to see whether pressure is leaking, then check the toilets, taps and pipes, the check valve, the pressure switch or controller and the pressure tank. Often it's a toilet valve or a check valve. If the pump is old and worn, we'll give you the options for repair or replacement. Either way, you get a fixed price before any work starts. If sludge is the root cause, cleaning the tank and fitting a filter stops it happening again.
In southern Eastern Suburbs homes
Many homes in Pagewood, Eastgardens, Matraville and Little Bay have a rainwater tank and pump supplying the toilets and laundry. Most have never had the tank cleaned, and sludge clogging the valves is one of the most common reasons we find pumps cycling on their own.
Why locals call us
- Local to Matraville and the southern Eastern Suburbs
- Free on-site quotes, with a fixed price before any work starts
- Lifetime labour warranty on our workmanship
- 100+ five-star Google reviews
- Licensed plumbers and gasfitters (Lic. 398171C)
Common questions
Why does my rainwater pump keep turning on and off?
Usually a leak somewhere in the system, often a running toilet, or a worn check valve, pressure switch or pressure tank.
Is it bad if my pump runs at night?
Yes. It means pressure is being lost, which wears out the pump and wastes power and water. It's worth finding the cause.
Can a rainwater pump be repaired?
Often. Check valves, pressure switches, controllers and seals can be replaced. If the pump itself is worn out, replacing it may be better value.
Does tank sludge affect the pump?
Yes. Sediment drawn up from the tank clogs valves and switches and wears the pump. Cleaning the tank and adding a filter helps.
Related help: rainwater tank maintenance, rainwater tank guide, I can hear water running and leaking toilets. Local pages: Pagewood, Eastgardens, Matraville and Little Bay.