Artesia, alongside HRWallingford, was recently commissioned by Ofwat to review how smart metering can improve the quantification of consumption and night use in the Water Balance. In this report, we set out an ambitious framework for accounting for customer consumption, however it is also highly dependent on wide-spread and reliable smart metering.
Therefore, as part of this project, we set out a transition approach to move from current reporting of consumption towards a fully measured system. This is built on the existing maximum-likelihood-estimation approach and includes a new approach for reporting bottom-up distribution leakage.
This method needs to accommodate very low levels of smart metering below 30%, and very high levels exceeding 90%. Our approach uses the existing options of zonal or District metered area (DMA) resolution and focusses on three scenarios as shown below:
We have recommended area based and individual property approaches to evaluating night use in low smart metering areas, which build upon existing individual household monitor and small area monitor methodologies. Moving forward into AMP9 we have recommended that companies begin to integrate smart meters into hybrid approaches alongside these existing monitors. For non-household night use we have recommended an improved variant of the existing night use to daily consumption modelling approach that incorporates non-household smart meters.
We have recommended a daily DMA or zonal level water balance when meter penetration in an area exceeds 90%.
We believe these changes bring existing guidance up to the standard that most companies are working to and provides a clear transition to a more accurate bottom-up leakage figure. Whilst set out for reporting over a short transition period, it offers an accurate approach that is fit for purpose beyond 2035 for both operational and reporting (If desired) purposes.
Our report to Ofwat is freely available online and will inform a consultation into leakage reporting in Summer 2026. Please do get in touch if you have any questions.
