Topics

Earth holds about 1.386 billion cubic kilometres of water. Only 2.5% is fresh, most of that is frozen, and the liquid fresh wate…

Rivers deliver dissolved minerals to the ocean continuously. Evaporation removes the water and leaves the minerals behind. Over …

96.5% of Earth’s water is in the oceans. Its salinity, circulation and chemistry set the conditions everything else operates wit…

Water breaks most of the rules its molecular weight predicts. It should be a gas at room temperature, and ice should sink. Almos…

Almost all the world’s liquid fresh water is underground. It is invisible, slow, and the easiest resource in the world to overdr…

A river is a flow, not a store. Understanding discharge, baseflow and the flow duration curve explains almost everything about w…

Solid, liquid and gas — and the transitions between them, which move more energy around the planet than almost anything else.

Frozen water is the world’s largest freshwater store and its most important natural reservoir — releasing water in summer, preci…

Water chemistry is mostly a record of what the water has flowed over. Hardness, pH, alkalinity and mineral content are all set b…

Density, viscosity, surface tension, specific heat, conductivity — the numbers, what they mean, and why so many of them are anom…

Water moves continuously between ocean, atmosphere, land and ground. Understanding the rates — not just the pathways — is what m…

The return half of the water cycle, and the reason a rainfall deficit becomes a drought faster in a hot year than a cool one.

Drought is not one thing. It is four, they arrive in sequence, and confusing them is why "the rain has ended the drought" is so …

Most of the way climate change is experienced is through water: too much, too little, at the wrong time, or the wrong temperature.

ENSO does not change how much rain falls globally. It changes where it falls — and the pattern is repeatable enough to be useful…

The immediate danger of a flood is the water’s force. The longer danger is what it carries — sewage, fuel, chemicals and everyth…

A wildfire rarely contaminates a water supply while it burns. The damage arrives with the first heavy rain on a burned catchment…

Water quality reports are written for regulators, not readers. Here is what each part actually means, and the four things people…

Boil water notices, contamination incidents and post-disaster supply. What works, what does not, and what makes things worse.

What triggers one, what to do, how long boiling needs, and the situations where boiling makes the problem worse rather than bett…

Home test strips and TDS meters answer a narrow set of questions. Understanding which questions they answer — and which they onl…

Cloudiness is not a health parameter, and it is the most closely watched number in drinking water treatment. Both of those are t…

There is no universal number, the eight-glasses rule has no evidential basis, and the reference values people quote include the …

The diseases water carries, why chlorination was the most consequential public health intervention of the twentieth century, and…

Roughly 55 to 60% of an adult is water, but the figure varies more between individuals than most people expect — and body compos…

A neutral comparison across regulation, composition, cost, safety and environmental impact. The differences are real, and mostly…

Alkaline water, hydrogen water, structured water, oxygenated water and the rest — what each claims, what the evidence shows, and…

From a river or borehole to your tap, through a sequence of barriers designed so that no single one has to work perfectly.

Yes, for specific things. The single most useful fact about any filter is what it is certified to remove — which is almost never…

Separating salt from seawater takes energy — physics sets a floor of about 1 kWh per cubic metre, and modern plants get within a…

Why combined sewers discharge to rivers at all, why recorded spills rose so sharply, and what would actually fix it.

Wastewater treatment is mostly a controlled biological process: micro-organisms are fed the pollution and then removed.

Treated wastewater is already a major water source, mostly without anyone noticing. Planned potable reuse just makes it explicit.

Why leakage figures are so hard to compare, why percentage measures mislead, and why "just fix the leaks" is harder than it soun…

What you actually pay for, why metered and unmetered bills differ so much, and why cross-country bill comparisons are usually me…

Data centres use water for cooling. The widely circulated per-query figures are scenario outputs, not measurements — and the lar…

Agriculture takes about 70% of global freshwater withdrawal. Households take under a tenth. Almost every popular water-saving co…

Seventy percent of global withdrawal, most of it consumed rather than returned — and the efficiency measures that seem obvious f…

What actually moves the needle, ranked by effect — and an honest account of how much household saving matters in the wider pictu…

The figure for a kilogram of beef or a cup of coffee is a global average that mixes rainfall with abstracted water. Useful, and …

Generating electricity takes water, and moving and treating water takes electricity. The two systems constrain each other in way…

Industrial water use spans processes with almost nothing in common — from steel cooling to semiconductor rinsing at a purity bey…

Four nations, four regulatory systems, three ownership models and a rainfall gradient that puts the water in the north west and …

Scarcity is rarely about how much water exists. It is about timing, distribution, quality, infrastructure and governance — physi…

The global picture, the service ladder that defines it, and why "access to improved water" and "safely managed water" describe v…

The rules governing every number on this site: provenance, basis, native geography, conflicting sources, and what happens when H…

Nutrient enrichment triggers a chain that ends in oxygen collapse. The killing step is not the algae growing but the algae dying.

There are around 200 chalk streams in the world and the great majority are in England. They are among the rarest freshwater habi…

Tiny by volume, disproportionate in effect. Wetlands filter water, attenuate floods, and hold more carbon per hectare than almos…

Four thousand years of moving water and, much more recently, of understanding why it makes people ill. The second insight arrive…

What is genuinely changing in water: membranes, sensing, leak detection, digital twins and reuse — and what is being oversold.

Over 260 river basins cross international borders. The record of cooperation over them is much better than the popular narrative…

What a reservoir actually does, why percentage full is a misleading comparison, and the trade-offs every dam makes.

Most of what a water company owns is buried, most of the cost is in the pipes, and most of it was laid by people who are no long…

What hardness actually is, why it costs you money, why it has no health effect, and which of the many products sold to deal with…

Wells, springs and boreholes are not regulated or treated like mains water. If you are on one, the responsibility for its safety…