Key updates to the British Standard for Rainwater Harvesting BS 16941 2024

The new British Standard (BS) retains many of the existing system design considerations and incorporates a new consideration to cover the potential for pollution within the rainwater supply. These include…

• Local annual rainfall (no change)
• Size of the collection surface (no change)
• Surface materials (no change)
• Air pollution and pollution from collecting surfaces (new)
• Risk of contamination (no change)

Consideration should also be given to the intended use of recycled rainwater. Certain uses may require additional filtration. These considerations may require additional physical, chemical, or biological filtration. 

Our recommendation

Our engineers always recommend a third stage of filtration to protect vital components within the system and improve water quality. Stormsaver can provide automatic backwash filtration (pictured here) for additional filtration requirements. This provides an intelligent self-cleaning filter to minimise maintenance requirements.

Mains water backup systems ensure the water supply continues to points of use even during low rainwater periods. Ensuring the backup is designed correctly is essential. 

As always, the mains water backup must have a physical air gap to prevent contamination between category 5 rainwater and mains water supplies. This can be achieved via a backup within a break tank or main storage device. The amended standard now demands a ‘control mechanism’ on the backup to minimise mains water use. 

Our recommendation

Stormsaver systems have utilised these protections for many years. Protection mechanisms are crucial because solenoid valves on the backup can fail open allowing precious mains water to continually overflow.

Stormsaver takes advantage of mechanical shutoff valves (demonstrated in the image) on the mains water inlet within our non-pressurised and combi-style arrangements. On systems with no break tank, our intelligent control panel can provide mains water overrun alerts. These vital alerts are sent to the building user for remedial action. 

In our experience, including a break tank within the design is the best approach. The break tank protects against failure allowing a continued water supply to outlets. Topping up a break tank with mains water is also much more efficient due to the smaller surface area. 

Another notable change within the new BS includes the incorporation of a visible and/or audible alarm to notify building users of operational status.

Our recommendation 

Stormsaver systems are unique within the market in that every component is designed to communicate with our intelligent control panel. Surprisingly, not all systems available on the market communicate to a central control panel and many of these components operate in isolation.

We call this the 'holistic' approach to rainwater harvesting as our system knows when and where the failure has occurred. Because of this, Stormsaver can provide a range of different monitoring methods, including alerts on the control panel and BMS notifications. 

Just let our team know about your BMS requirements. 

Within the new BS there has also been a push to make components more energy efficient. Any associated pumps used to supply rainwater across the building should be supplied with electricity from renewable energy where possible.

Our recommendation 

We already have a plug-and-play product for exactly this! StormStation houses controls, pumps, tanks, and filtration in one simple-to-install unit. StormStation can be supplied with solar panels to supply renewable energy. The inclusion of solar panels helps the unit to become carbon neutral after 25 years. 

Unlike other above-ground solutions on the market, StormStation is supplied with self-circulating UV disinfection. Any water that is stored above ground is susceptible to legionella; therefore, UV disinfection is essential. This feature provides constant disinfection for stored rainwater. 

StormStation can be used for retrofit and new build projects. StormStation is supplied in a range of capacities between 3,000-20,000 litres, covering the most common tank sizes for rainwater harvesting in the UK. 

Learn more about StormStation here.