Rainwater Harvesting

Following a trial that ran from 2017 to 31 March 2020 we have we now offer a full or partial connectivity allowance for areas covered by a rainwater harvester where:

  • There is NO overflow to our network

  • The additional sewerage volume can be measured and charged for

Therefore the retailer must confirm during the course of the application that:

  • The overflow from the rainwater harvesting system does not drain to sewer – the retailer must be able to demonstrate this to our satisfaction by providing plans and or a site inspection.

  • Any changes to drainage arrangements must be notified to us immediately.

  • The metering of the rainwater harvesting system must allow the additional volume of foul drainage discharged to be calculated and the retailer needs to confirm that they can present this to us in a way to enable us to correctly bill them via the market for the relevant usage.  This may differ for each system depending on set up. Meters will be set up in the market to allow automated billing.

  • Should the customer change retailer the new retailer will need to provide the information in the same way to enable us to correctly bill them for the relevant usage.

  • Access to the meter(s) must be provided on request

  • Meter(s) to assess the additional sewerage discharge must meet the regulations and standards we consider acceptable – these can be provided on request but are shown below:

  • All new meters manufactured to meet & comply with global and EU standards (ISO:4064, MID,)

  • Meter performance to be compliant with Measuring Equipment (Cold Water Meters) Regulations – these regulations form part of the Weights and Measures Act 1988.

  • All compliant meters are marked with ‘CE’ on the meter – this demonstrates compliance with EU legislation.

  • Older meters (manufactured prior to 2006) are marked with a Trading Standards kite mark. These will comply with the existing standards at the time the meter gained the relevant approvals.
  • General Guidance

    It is highly unlikely that a rainwater harvesting system would be built without an overflow – if the rest of the site is connected for surface water, it is highly likely that the system will overflow to sewer.

    It is likely that any rainwater harvesting system will have a mains top up for periods of dry weather. Metering arrangements must be understood to ensure that this volume of water is not charged twice.