Rainwater – Pump Issues
This photo shows a fairly typical pump installation.
An electric pump with pressure sensor control. It’s even got a fairly large diameter flexible suction hose between the tank and the pump.
So…..What are the issues?
Well water is an incompressible substance so every time some water leaves the system the pressure drops enough to trigger the sensor and the pump starts…………..That happens whether you are having a shower, putting a splash of water on your hands, or even a couple of drops dripping from a slightly leaky toilet valve.
This leads to Three Issues.
Efficiency
Electric pumps are designed to pump efficiently at their designed rate. If you are using water at a slower rate than the design rate the pump wastes energy trying to pump at its designed flow.
A lot more power is used to start the pump then when the pump is running for some time.
A Recent Study for the CSIRO showed that a typical domestic rainwater system used more energy than traditional centralised water treatment and distribution systems.
Pump Life
The main thing that wears pumps out is continually starting rather than running.
Noise
Because the pump runs frequently you are more likely to notice the noise. If you have got a leaking tap or toilet valve it will be starting up several times through the night.
Solutions
If you have got a large block with a slope of several metres it may be possible to install a header tank. This solution however is not normally possible for most of us.
The best solution for the average house is to upgrade by installing a Pressure Tank. Follow the link to find out more.
For more posts about tank water see the Rainwater Section under the Sustainability Tab