2018 may well be remembered as the year one of the world’s great tourist destinations ran out of water.

In a startling reminder that our world’s most precious resource is becoming increasingly scarce for too much of the population, Cape Town hit the headlines for declaring a date for Day Zero: the day on which city taps run dry.

But long queues and limited water supplies are already happening in many other less headline-worthy locales, reminding us of the need for better and fairer management of Earth’s water supply.

Already more than 60% of humanity lives in areas of water stress, where the supply of water cannot or will not continue to meet demand. If water is not managed more prudently – from source, to tap, and back to source – the crises observed today will become the catastrophes of tomorrow.

This year’s The State of the World’s Water reveals that the number of people defined as without clean water close to home has gone up, with new entries in our ranking.

Some 844 million people are now struggling to access life’s most essential requirement – almost 200 million more than previously counted.

Statisticians now record both what source people obtain their water from and how far they travel for it. Anything longer than a 30-minute round trip no longer counts as access. As a result, countries including Uganda and Niger are now counted among those with the lowest rates of access; many countries also face intense competition with agriculture and industry for water, and evergrowing challenges from extreme weather, political instability, conflict and displacement.

New data that links water access to household wealth also shows that, even in countries making progress, there are still vast discrepancies between richest and poorest.

As this year’s report demonstrates, wherever you are in the world, it’s the poorest and least powerful who are most often without clean water.

That means those who are older, ill, disabled, who live in a remote or rural location or have been displaced, or who are of a caste, ethnicity or religion likely to be discriminated against.

Inequalities in wealth and power, attitudes in society and culture, and limited resources mean they are also hardest to reach. Gender intensifies this inequality; it is mainly up to women and girls to find and fetch water, or to find ways to adapt when it is scarce.

Consider this: a woman collecting the UN-recommended amount of 50 litres per person for her family of four from a water source 30 minutes away would spend two and a half months a year on this task.

Importantly, 2018 presents a chance for change. Nearly three years ago, world leaders passed the UN’s Sustainable Development Goals, a promise to end extreme poverty and create a fairer, more sustainable world. This summer, Global Goal 6 – to deliver access to water and sanitation to all – will be reviewed at a high-level political forum in New York, to measure progress and press ahead for more.

Around 289,000 children under five die each year of diarrhoeal illness directly linked to dirty water, inadequate toilets and poor hygiene. This shouldn’t be normal. It is a crisis we cannot ignore.