Water Risk Assessment Tools for Companies: Aqueduct, Water Risk Filter and GEMI Compared

Three free tools carry most corporate water risk screening: the WRI Aqueduct Water Risk Atlas, the WWF Water Risk Filter and the GEMI Local Water Tool. This guide compares them, shows how a basin screening turns into a site action plan, and where the result feeds into ESRS E3 disclosure.

What a Corporate Water Risk Assessment Covers, and What It Is Not

A corporate water risk assessment works on two layers. The basin layer asks how much water stress, flood exposure, drought frequency and regulatory pressure exist in the catchment around each site. The operational layer asks how much that site withdraws, consumes and discharges, and how fast production stops when water becomes scarce, too warm or too expensive. A site in a relaxed basin can still carry high operational risk if one cooling water permit is the bottleneck.

This is not a water hygiene risk assessment. In the UK the same three words usually mean a water safety review of building water systems, a Legionella risk assessment with temperature and sampling regimes, a named duty holder and a fixed risk assessment review frequency. That is a building compliance duty. What this page covers is a resource and supply chain question about catchments, sites and suppliers.

An example of what the corporate version produces: a beverage producer with plants in southern Spain and northern Germany gets two different answers from the same tool run. The Spanish site shows basin stress that will constrain future abstraction permits. The German site shows a discharge temperature limit that bites during heatwaves. Both are water risks, only one of them is about scarcity, and they need different measures.

Water Risk Assessment Tools Compared

All three tools below are free. The practical question is not which one is best, but in which order to use them.

The usual sequence is Aqueduct for the portfolio, the WWF Water Risk Filter to sort the flagged sites and look forward, and the GEMI Local Water Tool where a site needs its own numbers.

My position on all three: a global basin screening is a screening result, not an audit safe site conclusion. These datasets are modelled at catchment resolution, so they tell you where to look, never what is true at the fence line. The tool is the starting point, not the endpoint.

From Basin Screening to Site Action Plans

Before any tool run, collect the internal data the global datasets cannot supply:

• Annual withdrawal and consumption per site, kept apart, not as one group figure
• Source of supply per site: municipal, own well, surface water, reused water
• Cooling dependency: which process stops first if intake water is restricted or arrives too warm
• Discharge permits with their volume and temperature limits, and their renewal dates
• What water and one hour of unplanned downtime actually cost at that site

The sequence from there is short. Build the site list, run the basin screening against it, merge the internal figures above into the flagged locations, then validate those locations locally with the plant manager and the permit file. Local validation is where most screenings fail: a basin score says the catchment is stressed, while the plant has a long term abstraction contract that makes the risk a price risk rather than a volume risk.

Only after validation is an action plan worth writing. It should name a measure, a site, an owner and a date, for instance a cooling circuit conversion at the one plant whose permit expires soonest. A water data dashboard keeps that cycle from becoming a yearly archaeology project.

Water in ESRS E3 and the EU Water Resilience Strategy

The screening output is also a reporting input. ESRS E3, the European standard on water and marine resources, asks for water consumption and for the share of it in areas of water stress. That share cannot be produced without exactly the basin screening described above, which is why the assessment and the disclosure should be one workflow rather than two.

Scope is the part to check first. The Omnibus directive narrowed the range of companies obliged to report under the CSRD and moved the timetable, so confirm your own reporting year before building a data collection around E3. Companies outside the obligation still get the demand indirectly, through customers, lenders and CDP Water questionnaires.

Two policy layers sit beside it. The European Commission's Water Resilience Strategy treats water as a strategic resource and expects companies to bring water risk into financial decisions, and the EU Taxonomy sets technical criteria for water related activities and for the do no significant harm test on water.

Linking Water Screening to Climate Scenario Work and Supplier Sites

In practice a water screening and a climate risk analysis start from the same artefact: a clean list of sites with coordinates. Drought and water stress are physical climate risks anyway, so the site list, the coordinates and the scenario choice should be assembled once and used for both. Running them as separate projects duplicates the expensive part and produces two site lists that disagree within a year.

The same list logic works upstream. Before sending a supplier water questionnaire to everyone, put the tier one supplier sites through the basin screening and only question the ones in stressed catchments. Screening triages, questionnaires confirm, and asking 300 suppliers about water when 30 of them sit in stressed basins mostly generates data nobody reads.

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