Types of Rainwater Harvesting System
There are many different varieties of Rainwater Harvesting systems on the market, in principle they all perform the same function, however your existing water course infrastructure and water demands will help determine the system that is best for you.
- Domestic systems, are either direct or indirect i.e. gravity / header tank fed
- Garden / irrigation systems, both above ground and underground.
- Commercial systems – these are usually bespoke systems
- Greywater recycling – these are usually bespoke systems
Rainwater Harvesting systems in more detail…
Gravity Fed Systems
Gravity Fed Rainwater Harvesting systems simply collect rainwater from the roof of the property and passes it through a filter which removes any leaves and twigs. Thereafter, the water is pumped into a sub-surface storage tank.
As the water settles in the storage tank, the heavier particles drop to the bottom of the tank.
The stored water is pumped to a Header Tank located in the loft. The Header Tank then uses its own gravity pressure to feed the water demands. The pressure provided by a Gravity Fed system is not enough to supply washing machines or dishwashers.
However the advantage of this system is that it is easier to install and requires less pump power, giving the pump a longer life expectancy.
Direct Rainwater Harvesting systems have a key advantage over gravity fed systems as they can be used for dishwashers and washing machines as well as toilets and gardens; this is because they work as a pressurised system.
The rainwater is collected through your existing drainpipe system and then flows through the first filter process which removes larger particles of leaves and twigs. It is then collected and stored in the enters the storage tank
In the tank, the rainwater settles and smaller particles such silt float to the bottom of the tank.
When the water is needed in the house, the water from the tank is directed through a smaller filter to thoroughly clean it before it enters the house.
The storage tank is connected to the existing mains water supply to ensure that if there is insufficient stored rain water it can then be topped up.
The key benefit of a Direct System is that it can be used for washing machines and dishwashers, as well as toilets, and gardens. In order to use rainwater for to be used as potable water it would have to go through a much stricter and more expensive filter and cleaning process.
Commercial Rainwater Harvesting systems work exactly the same way as domestic rainwater harvesting systems, with the exception that larger roof space means that they can collect more rainwater therefore can supply larger water needs.
Commercial rainwater harvesting systems are used principally for toilets and are typically only gravity fed systems. For those with large water needs, such as nurseries or farms gravity fed rainwater systems can offer significant savings.
Please note that underground storage of rainwater eliminates the growth of algae as the water can easily be filtered before entry thus also making it much cleaner.
Another advantage of underground storage is that you can have large amounts of storage without taking up room in your garden.