Communal Rainwater Harvesting

Quick explanation

1. Rainwater is collected from the roof of each home.
2. Preliminary filtration removes large debris (like leaves).
3. Rainwater enters the main storage tank via an inlet calmer.
4. Sedimentation allows sediment to settle on the base of the tank.
5. Rainwater is pumped from the tank via a floating suction hose.
6. Rainwater is transported to multiple header tanks throughout the development.
7. Rainwater is boosted to each home for non-potable use.

Detailed explanation

Transportation

Rainwater is collected from the roof area of each home and transported via separate pipework. Separate pipework will prevent the cross-contamination of the roof water and surface water runoff.

Roof rainwater and surface water runoff are always kept separate as only roof rainwater will be reused. Surface water contains additional contaminants which are not suitable for reuse in most instances.  

Roof rainwater is transported to a central location on the development.

Pre-Filtration

Leaves and undissolved particles are separated before the main storage tank via a pre-tank filter. Pre-tank filters trap any debris above 1mm on a mesh surface, allowing clear rainwater to flow into the tank.

Stormsaver pre-tank filters are designed to be fully removable from ground level for maintenance purposes. Stormsaver Systems integrates the pre-tank filter within a separate chamber in the main storage tank for ease of installation.

Storage

After preliminary filtration, rainwater enters the main storage tank via a calmed inlet.

The calmed inlet prevents the disturbance of fine sediment in the base of the storage tank. Rainwater Harvesting tanks are designed to naturally overflow (around three times per year if not reused) to prevent stagnation.

Submersible pumps sit within the storage tank and draw water from the cleanest part of the storage tank via a floating suction filter.

Rainwater tanks can also be connected to attenuation capacity via Active Attenuation. Learn more here.

Additional filtration

Best practice specifications will include an optional third stage of filtration to protect the system against smaller debris. Stormsaver provides Automatic Backwash Filtration to achieve a self-cleaning solution for third-stage filtration. Learn more here.

Secondary storage

Rainwater is boosted from a central storage tank to smaller header tanks around the development. The number of header tanks is determined by the location and number of homes served by the rainwater harvesting system.

Mains water top up

An intelligent mains water top up is achieved in the header tank via a WRAS-compliant air gap.

Stormsaver Systems are supplied with mains water protection in the form of a mechanical shut off valve. This vital feature protects against waste in the event of a solenoid valve failure.

Did you know that many regions in England are considered ‘seriously water stressed’ by the Environment Agency? As the country's future water deficit grows to an additional 5 billion litres per day by 2050, communal rainwater harvesting offers a long-lasting solution to improve water efficiency within homes.

Issues around water scarcity are not the only problem with water in the UK. Water management is also an issue with aging sewage infrastructure regularly reaching capacity and releasing pollutants into nearby natural water courses.

Rainwater harvesting is a solution to both of these problems. Not only can systems reduce per capita consumption of water by replacing precious drinking water with recycled rainwater in non-potable outlets, but rainwater harvesting also prevents large volumes of surface water from entering the over-capacity drainage network.

Rainwater harvesting is proven to reduce water consumption in residential properties by up to 55%.

• Remove ownership and maintenance responsibilities from the homeowner to a management organisation.
• Remove internal components from homes, assisting with reduced risk of cross-contamination between the rainwater and mains water supplies.
• Prevent homeowners from switching the system off due to a lack of knowledge.
• Can be linked with onsite attenuation capacity for a more cost-effective per-dwelling solution.
• Can work as part of a wider biodiversity plan whilst saving space by reducing the required capacity of swales and ponds.
• Utilise commercial grade components for extended lifespan.
• A single point of maintenance.
• Mitigate the need for consumer behaviour changes in water usage by supplying them with rainwater.

Many rely on the ‘water fittings’ approach for achieving greater water efficiency within homes. Water fittings are technologies that reduce the use of water in key outlets, examples include air-assisted showers, aerated toilet flushing, and dual-flush toilets. Communal rainwater harvesting is the optimal water-saving solution because…

• Communal systems cannot be simply removed by homeowners for high water using alternatives.
• Using rainwater rather than mains water is commonly seen as indistinguishable.
• A lasting piece of infrastructure which can be monitored, maintained, and enforced.
• Offers centralised monitoring of water levels and water savings.