Wessex Water are hosting an Open Data Day¹ next week on 9th-10th March, with the "Stream Challenge Statement 2026" of:

How might we, using a variety of data sources, better understand and communicate national, regional and local water availability, so that everyone* can make better- informed water use decisions?

individuals, households, organisations, government and regulators

Data, understanding, communication, cooperation, better decision making. This is music to my ears!

Let's go Wessex Water!

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Wessex Water Challenge Statements

Specific challenges that take the challenge of water efficiency to the next level.

1: How might we bring together useful data from water companies, the Environment Agency, Defra and others to build a clear, joined-up picture of water availability across the country?

Right now, the data exists: reservoir levels, river flows, groundwater status - but it's fragmented, published in different formats, and hard to stitch together. Imagine if we could assemble that into a single, trustworthy view that updates regularly and is easy to use.

2: How might we make the complexity of national, regional and local water availability understandable and meaningful to a wide audience - from school pupils to policy-makers? Water availability isn't simple; it varies by geography, climate, infrastructure, regulation, and demand. Right now, even when datasets are openly published, much of the insight is locked behind technical language or complex dashboards. This sub-challenge is about transforming complexity into clarity. Participarts could explore how we help people understand where water is plentiful, where it's under pressure, and why it matters.²

3: How might we design a simple, standardised water availability alert system, similar to UK flood and weather warnings, that uses open data to provide timely, actionable information for households and businesses? The UK already has well-understood alert systems for floods and severe weather - they use clear language, consistent categories, and trusted data sources. But we don't currently have anything comparable for water scarcity, and this sub-challenge invites participants to imagine what such a system could be.

4: How do we identify which pipe leaks the most within a particular network area to target pipe replacement schemes? Our 12,000 km distribution network supplies around 600,000 households and 45,000 commercial customers. It includes trunk mains, distribution mains and service pipes, with ownership boundaries varying by property type. Pipe failures and leaks are influenced by factors such as material, age, network operation, weather extremes and soil conditions. While we estimate leakage at zone level, it remains difficult to identify which specific pipes to prioritise for renewal. As a result, much of our activity is reactive rather than proactive. Understanding pipe risk-based on characteristics, environment, and repair history-can help target the sections of the network most likely to leak. Improving this insight supports water efficiency: by replacing or repairing high-risk pipes before major failures occur, we reduce water loss and minimise supply interruptions for customers.

5: Can we distinguish suspected leaks from legitimate use using Smart Meter continuous flow data? Around 50,000 Smart Meters are installed each year across our region. Unlike traditional meters read twice a year, Smart Meters provide hourly-and often 15-minute-data, greatly improving our ability to track water use. A key insight from this data is the detection of continuous flows, where water use never drops to zero. In households, this often signals a potential leak, though some night-time use may be legitimate. Non-household customers show more varied patterns, and sustained night use may be normal for some industries.

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Some more research around this.

What Units Could be Used to Communicate Water Use / Availability?

Whilst reading Environment Agency's Public water supply - drought risks, impacts and actions: Drought prospects for spring 2026 the thought occurred to me about communicating water availability. We need a relatable value.

As David MacKay says on page 24 of his book Sustainable Energy - Without the Hot Air

Most discussions of energy consumption and production are confusing because of the proliferation of units in which energy and power are mea- sured, from “tons of oil equivalent” to “terawatt-hours” (TWh) and “exa- joules” (EJ). Nobody but a specialist has a feeling for what “a barrel of oil” or “a million BTUs” means in human terms. In this book, we'll express everything in a single set of personal units that everyone can relate to.

The unit of energy I have chosen is the kilowatt-hour (kWh). This quantity is called “one unit” on electricity bills, and it costs a domestic user about 10p in the UK in 2008. As we'll see, most individual daily choices involve amounts of energy equal to small numbers of kilowatt-hours.

When we discuss powers (rates at which we use or produce energy), the main unit will be the kilowatt-hour per day (kWh/d). We'll also occasionally use the watt (40 W ≈ 1kWh/d) and the kilowatt (1 kW = 1000 W = 24 kWh/d), as I'll explain below. The kilowatt-hour per day is a nice human-sized unit: most personal energy-guzzling activities guzzle at a rate of a small number of kilowatt-hours per day. For example, one 40 W lightbulb, kept switched on all the time, uses one kilowatt-hour per day.

A quantity of energy here is being expressed as 1 kWh. And a flow rate like power is expressed as 1kWh/d. What is the relatable units for water consumption & availability?

Maps

Who doesn't like a good map?!

High level map of coverage area includes major settlements and the type of service provided (water, wastewater / sewerage, or both).

Map of reported leaks and maintenance works

Financial Data

2023-2024 Ofwat "Monitoring Financial Resilience Report" included this table of key financial metrics on page 13.

Leaks

Video explaining how leaks are reported, promises about timescales for investigation and repair, and about how the state will be left afterwards:

https://www.youtube.com/watch?v=d9lY5aMwefM

Hackathon

Data Sources - DEFRA - Catchment Data Explorer

• The link to download "boundary" contains over 900 features. And does not contain the boundary data. https://environment.data.gov.uk/catchment-planning/v/c3-plan/RiverBasinDistrict/9.geojson "2026_03_09_bad_data_uri.png"

• Why would a river basin extend into the sea? "2026_03_09_bad_river_basin.png"