Loughs Agency


Rainwater harvesting complete with UV disinfection chamber is central to the sustainability of Loughs agency HQ building in Prehen, County L/Derry, Northern Ireland.
RHI were approached by the CPD (Central Procurement Department) on behalf of the Loughs Agency and asked to put forward a rainwater harvesting system design which would best meet the requirements in terms of functionality and cost effectiveness of this existing building. The solution offered not only meets the demand requirements in terms of supplying the WC’s and the fresh water fish tanks but also utilised spawning tanks within the building which were no longer in use.


Project Spec
Sector Environment
Environment Department of Agriculture and Rural Development
Project Scope Rainwater Harvesting
Project Location Northern Ireland
Contract Value £6000
Client Loughs Agency HQ – Prehen – L / Derry – Northern Ireland


The water savings generated by the simple technology are very impressive. The rainwater is collected from over 300 square metres of roof surface and is then filtered to remove any organic debris washed down from the roof, before it is collected in re conditioned spawning tanks which now acts as a rainwater harvesting tank.

The filtered water is then automatically pumped back through the building on demand using a low power consumption multistage pump system. The harvested rainwater is used to replace mains water for toilet flushing within the building as well as providing water for fresh water fish tanks.

During periods of low or no rainfall, the system will automatically change over to mains water supply, ensuring continuity of supply to the building. As soon as the inevitable rainfall occurs, the system switches back to rainwater supply.



Back in 2011, 610 cubic metres of water was used. After installation of the rainwater harvesting system in December 2011, mains water consumption fell to 324 cubic metres up to end of November 2012. This amounts to a 47 per cent saving.

The plumbing firm was County Tyrone firm Shorts – their spokesman, Ian, said: “More public buildings should install these systems.”

Environment Officer with the Loughs Agency Dr Declan Lawlor said he was “very pleased with the success of the rainwater harvesting system.”

He said: “Every saving in water consumption aids the sensitive river ecosystem, leaving more water in the natural system for the creatures and plant life that need it.”