Choosing which type of pump to use in a rainwater harvesting tank

If you're experiencing a raise in your water bills for your farm, or if you find that water levels in your well or borehole have been decreasing, rainwater harvesting might be something for you. Rainwater harvesting is essentially the act of collecting the rainwater that falls on top of the roofs of your buildings to then gather it in a tank, from where it then can be pumped out into pipes where it's directed to where you need it. This ensures clean water for all purposes and is also environmentally sustainable as you are only gathering the water that is already provided to you by nature. The most important thing about a rainwater harvesting system is the water tank pumps used to get the water out of the tank. For you to choose which type of pump would suit you best, you need to know a few things about the two main types.

Constant pressure pump

A constant pressure pump is a pump that will recognise when someone turns on a water using appliance by sensing the pressure drop it causes to the water tank. It will then apply water steadily until what's using the water is turned off and the pressure is restored. The main positive feature with this type of pump is that it applies pressure constantly, which means you'll get water in you faucet as soon as you turn it on. This means you won't get any drop in pressure and thus the water will keep flowing all the time when you have an outlet on. The negative aspect of this is that it can cost you a bit for the electricity needed to keep the pressure.

Pressure vessel pump

A pressure vessel pump works similarly to the constant pressure pump, except it consists of two parts. A vessel is placed on the surface of the water in the tank and is the main component responsible for letting water out when you turn on an outlet somewhere on the farm. When you turn the water flow, the pump will then begin to refill the tank to once again put it under pressure. This means you eliminate the risk of running out of water in the tank. This type of pump could also use an unnecessary amount of electricity. If you want to minimise the effect of this disadvantage for both types of pumps, you could install a switch which you can turn off when you don't have a demand for water and thus save electricity.