DEFRA Rain Water Recycling


DEFRA new stores building located in Weybridge, Surrey is a light commercial industrial unit.

Aquaco were asked to provide a rainwater recycling (harvesting) system.

Our response
  • Aquaco proposed a system consisting of a 3,000 litre capacity rainwater recycling system complete with filtration, UV disinfection unit, pump sets, digital temperature and level sensors, header (break) tank, flow meter with BMS connections
  • The system will collect the rainwater from the roof areas in order to supply recycled water for the use of toilet flushing
  • The system will also record the amount of rainwater supplied to the toilets within the building against the supply of mains water for the system top-up

Schematic 3,000 litre underground rainwater collection tank




Collection tank invert levels




Typical header/break tank





Level sensor - features
  • Nine ranges in two sizes
  • Temperature compensated over  0 to 70°C
  • Lightning and reverse polarity protected
  • Rangeable up to 15 to 1 turn down on basic sensor rating
  • Power - 2 to 30 volts dc or 7 to 15 volts dc (current loop 4 to 20 mA - 2 wire)
  • Removable sensor head
  • On site setting and calibration by client
  • Fully vented with moisture prevention 





Panel Indicator Features
  • Low cost
  • Space saving - 110mm deep
  • One alarm relay fitted
  • Transmitter and transducer supplies


Panel Indicator Options
  • Up to three alarm relays
  • Isolated analogue output
  • Low voltage
  • Front panel buttons


Temperature sensor - technical specification
  • Range - 0-100 °C (or custom)
  • Sensor - PT100 CLA
  • Lengths - 50, 75, 100, 150, 'X' mm
  • Output - 4 - 20 mA
  • Power requirement - 10-30 VDC
  • CE approvals - BS EN 61326
  • Accuracy - ± 0.25 °C
  • Stability - ± 0.02 % / °C
  • Sensitivity - 10 µA / Volt
  • Ambient - 0-70 °C 









Water meter
  • Features and benefits
  • Specifications to class C & D to BS5728 & ISO4064
  • Tamper resistant construction
  • Fitted in any orientation
  • Grooved piston design
  • Easy to read counter
  • Leak-proof construction
  • Optional pulse output facility

Pressure and temperature
  • Pressure range: up to 16 bar
  • Temperature range: up to 50°C


Ultra-violet disinfection unit key benefits:

  • Proven chemical free disinfection
  • Effective on a wide range of pathogens including: Cryptosporidium and Giardia
  • Economical to operate and maintain
  • Easy to service