Understand the world’s water.

Governed datasets with a version, a stated methodology, an explicit licence position and a citation. Every coverage figure is computed from the data itself.

Quantitative findings drawn from the data Hydrionis holds, with the method published alongside and the limits stated in the same breath as the result.

What Hydrionis can answer for people who work with water professionally — and, on every page, where it stops.

• Data and APIs — governed datasets with versions, licences and citations
• Rights and reuse — what you may do with it, per source, per use
• Research and analysis — method published beside every result
• Discuss a data requirement — a geography, a period, a format, or a question

The measured record, brought up to the most recent period each publisher has released: rainfall, river flow, groundwater, reservoirs, drought and snow.

• Monitoring networks — every gauge, borehole, raingauge and reservoir Hydrionis holds a record for
• What the record is showing — findings computed from the data, recomputed each time the site is published
• River flow, water by water
• Groundwater
• Reservoirs — storage, level, inflow and release
• Drought
• Snow and ice
• When each source was last read

What comes out of the tap: where it came from, what is in it, what it costs, and what happens when something goes wrong with it.

• What is known where you live
• How tap water is made
• Hard water and limescale
• Contaminants — what gets into water, what it does, and what removes it
• Reading a water quality report
• Drinking water standards
• Water chemistry
• Minerals and ions
• Treatment processes
• Home filters
• Water bills
• Using less at home
• Tap against bottled

Who actually uses the water, what they use it for, who supplies it, and the infrastructure that moves it.

• Water use by sector
• Agriculture
• Industry
• Energy
• Data centres — sector context; facility-level use is not open data and is not held
• Water utilities
• Leakage
• Utility benchmarks
• Infrastructure
• Transfer schemes
• Desalination
• Water scarcity

Where the water is, how it moves, and what the long records show about it changing. Coverage here runs from very deep to explanatory, and each link says which.

• The water cycle
• Where Earth’s water is
• Rivers
• Lakes
• Aquifers
• Dams
• Snow and glaciers — the snow record is substantial; glacier coverage is explanatory
• Seas and oceans — three seas held; ocean coverage is explanatory rather than measured
• Climate change and water
• Floods
• Wildfire and water
• Chalk streams and wetlands
• What is not held, and what would close it

Where water goes after it is used, what reaches rivers and seas that should not, and who is held to account for it.

• How sewage is treated
• Storm overflows
• Water reuse
• Wastewater treatment works
• Algal blooms
• Pollution incidents and events — cause, impact, response and aftermath for each
• Enforcement actions
• The long history of water and public health
• What changed, and what was corrected

Every geography Hydrionis holds enough about to be worth a page — and the ones that are a row in a table instead, because a page promising more than a row can carry is worse than the row.

• Countries and territories
• UK water — the deepest Hydrionis geography
• Regions, continents and oceans
• UK nations, councils and basins
• Water bodies
• Monitoring networks
• Rankings — only where the metric is rankable
• Comparisons — enumerated, not generated

Questions answered from the record rather than asserted, with the method, the sources and the limits on the same page. Every figure recomputed each time the site is published.