Harvested rainwater is suitable for non-potable domestic applications such as WC flushing, laundry, washing vehicles and watering the garden. Rainwater is particularly beneficial to plants as it lacks the chemicals required to ensure mains water is suitable for human consumption.

On average every home uses 150 litres of water per person per day. Approximately 50 litres is used for non-potable applications that could be supplied by harvested rainwater reducing you water bill by 30–50%. With the cost of mains water expected to rise during the coming years, the financial benefit offered by a rainwater harvesting system is likely to improve, particularly for those with water meters.

No. Filtered rainwater must not be used in applications that require wholesome water such as drinking, cooking, bathing and dishwashing.

Although new builds are most suitable as the system can be designed at the outset, retrofitting is feasible, depending on accessibility of existing pipework.

Harvested rainwater is soft and can actually increase the lifespan and efficiency of domestic appliances such as washing machines especially for those living in hard water regions. Less detergent is needed, resulting in fewer pollutants from being released into the environment.

Tank size is determined by the amount of rainfall at the property, the roof area and the number of occupants using the system.

The rainwater storage tank should be located to ensure that the rainwater collected from the gutters travels into the tank under gravity. Installation of a control unit is required in a utility room or similar location. The tank should be located no further than 20m from the control unit to ensure the effective running of the pump and should be located a minimum of 1.2m from any fixed structure.

The use of a crane or forked truck can ease installation. If a forked vehicle is unavailable the tank can be manually handled by a minimum of four people using the handles provided on the tank. When moving the tank care must be taken to ensure that it is not damaged in any way.

Minimal maintenance of the system is required. Visual inspection for leaks and faults should be conducted alongside cleaning and clearing of filters and rainwater collection gutters to ensure that the rainwater harvesting system continues to operate efficiently.

Rainwater is very clean and clear in appearance and only becomes dirty when in contact with the ground. Roof collection surfaces will impact the colour of rainwater collected – for example, a green roof will result in greater discolouration of the collected rainwater. The RWH system should use a filter, calmed inlet and floating suction module to remove all debris and particles from the rainwater. It is important that filters and rainwater collection gutters are cleaned regularly to remove leaves and other debris.

This depends on the system chosen. Nu-Heat, for instance, offers two options. The first includes a control unit with an integrated silent running multi-stage pump for location in a utility room within the property and the second features a pump located inside the underground storage tank, ensuring that when the user is inside the property the pump will not be heard.

In the event of an empty rainwater storage tank the system’s control unit should automatically switch to mains water operation allowing the continued usage of all appliances served by the system. Once rainfall provides sufficient collection of rainwater in the storage tank, the control unit will automatically revert back to rainwater operation.

Currently there is no funding aimed directly at rainwater harvesting (although it can be used to achieve credits toward Level 4 of the Code for Sustainable Homes).

This depends on many factors such as the size of the tank, the volume of rainwater in the tank at the onset of a drought, the number of applications supplied by the rainwater and the number of occupants. If the rainwater tank is empty the system should switch automatically to mains water supply allowing the continued usage of appliances supplied by the system.