Installing a rainwater recycling system in your home can be a tremendously effective way to reduce your overall water usage, a boon for both the environment and your bank balance. However, any rainwater recycling system needs a means by which it can move water around your home to where it is needed (such as flushing toilets and sprinkler systems), and, unless you opt for a bladder tank setup, a suitable water pump will be required.
Fortunately, most rainwater recycling systems do not put undue strain on the pumps they require to function, but this doesn't mean you can just install any old pump and hope for the best. To get the best results from your rainwater recycling system, keep the following questions in mind when shopping around for a new pump:
What will your harvested rainwater be used for?
Your rainwater harvesting system will not require a large pump if all it does it water your herb garden from time to time, while an underpowered pump will quickly wear out when used in a large-scale recycling system. As such, you should choose a pump with an appropriate power and capacity for your home's needs.
To pull this off successfully, you will need to work out how much rainwater our home will require on any given day, as well as the rate at which water will need to be pumped. For example, a rainwater toilet flushing system requires a large amount of water (generally over a gallon), but high pressure and fast flow rates are not required since most toilet tanks fill up rather slowly anyway. On the other hand, an irrigation system for a small vegetable garden will not require enormous amounts of water, but this water will need to be quite highly pressurised, especially if the garden is located far away from the collection tank(s).
When working out these values, you should also bear in mind that you may require rainwater for more than one function at once. If this is the case, you should choose a pump that provides variable flow rates on demand, to prevent overpressure from damaging more fragile fixtures and plumbing.
What type of power supply should your pump use?
Most pumps suitable for home rainwater recycling systems are powered by a simple hookup to your mains electricity, and this setup is sufficient for most systems. However, homeowners wishing to save extra power and dedicated gardeners requiring near-constant irrigation may wish to consider choosing a low voltage pump. These pumps are still powered by electricity but draw much lower voltages to decrease your energy consumption when the pump is in use.
While these pumps are more environmentally friendly, they can also be more expensive, so you should consider a low voltage pump as a long-term investment. Low voltage pumps may also be unsuitable if they are located far away from an electrical hookup, as low voltage pumps require much thicker (and more expensive) wiring to function safely.
Does my chosen pump have a float switch?
Float switches are automatically activated devices that cut power to your pump when your water tanks are empty, and are always a desirable feature when choosing water pumps. However, they are more of a necessity than an optional extra when it comes to rainwater recycling, as the supply of rainwater you receive will never be reliable and you may find your tanks emptying regularly during warmer months. Running a pump dry causes massive heat buildup that can cause severe damage, even if the pump is only operated for a short time.