Real countries, real policies, and what the numbers did afterwards — including where it went wrong.
Singapore built a supply that does not depend on rain. Its 1962 agreement with the Malaysian state of Johor entitles it to up to 250 million gallons a day of raw water and expires in 2061. Against that it now runs five NEWater factories, which purify treated sewage, and five desalination plants, alongside local catchment. Total demand is about 440 million gallons a day.
What happened. Household use fell from 165 litres per person per day in 2003 to 141 in 2023, after rising to 158 during the pandemic. NEWater was targeted to supply up to 55% of demand by 2060. The national water agency states that by 2065, when total demand could almost double, NEWater and desalination will meet the majority of it.
The catch. The bill is electricity. Water made from the sea or from sewage costs energy in a way that water taken from a river does not, and Singapore imports its fuel too. It is also why Singapore scores 7.0% on this page's measure: a supply that does not come from renewable freshwater resources never appears in the fraction.
Ministry of Sustainability and the Environment, Singapore — water policy; Public Utilities Board — Singapore's Water Loop; National Library Board — NEWater (figures valid as at December 2018)
Israel did two things at once: it built five large seawater desalination plants on the Mediterranean between 2005 and 2015, and it plumbed its sewers into its farms. Treated wastewater is piped to irrigation rather than to the sea.
What happened. A 2023 report by a United States Environmental Protection Agency delegation put reuse at nearly 90% of Israel's treated wastewater, going to irrigation, as of 2022. The Sorek plant alone produces 624,000 cubic metres a day, serving over 1.5 million people and about 20% of national municipal demand. Some utilities have cut water lost in the pipes to under 5%.
The catch. Good sources disagree on how much of Israel's drinking water is desalinated. The EPA report says about 90% of the domestic freshwater supply. Mekorot's vice-president for engineering told the Times of Israel in August 2023 it was 60% to 80%. Fanack Water, citing Kramer and colleagues (2022), says the five plants make 50% of potable water. The honest answer is somewhere in that range, and it depends what you count.
US Environmental Protection Agency, 'From water stressed to water secure: lessons from Israel's water reuse approach', EPA-822-S-23-001, March 2023
Cape Town ran out. Three dry winters from 2015 emptied the dams to 39% by November 2017, and the city named a date — Day Zero — on which taps would be shut and residents would queue at collection points. It answered with punitive tariffs, level 6B restrictions from 1 February 2018, pressure reduction across the network and about 250,000 water management devices installed on household meters.
What happened. Daily consumption fell from 1,200 million litres in February 2015 to 511 million litres by 12 March 2018 — a drop of 689 million litres a day, 400 million of it in the final year alone. Day Zero never arrived, and by July 2023 the dams were close to full.
The catch. It did not last. In February 2026 Cape Town was using 1,056 million litres a day, or 212 litres per person against a world average of 120 to 160, and missing its own summer target of under 975. About 23% of the water is lost to leaks before it reaches anyone. Crisis behaviour is not a policy; it expires.
GroundUp — 'How Cape Town more than halved its water usage' (13 March 2018) and 'Cape Town's water use remains too high despite Day Zero lessons' (3 February 2026)
After the Millennium Drought, Sydney built a reverse-osmosis desalination plant at Kurnell for about A$1.9 billion, able to produce 250 million litres a day — up to 15% of the city's water. It was switched on in January 2010. Then it rained.
What happened. The plant was ordered to stop producing on 1 July 2012, when dam storage passed 90%. It restarted only after storage fell below 60% on 27 January 2019, and delivered water again from March 2019. That is roughly six and a half years in which it made no water. The regulator IPART estimated in December 2018 that a typical Sydney household paid around $85 a year for the plant's fixed costs in shutdown mode, plus about $45 more once it ran.
The catch. An insurance policy you never claim on is not the same as money wasted, and the plant did carry Sydney through the 2019–20 drought. But the fair reading is that the timing was wrong, not the idea: the asset was bought at the bottom of a drought and paid for through the wettest years that followed.
Sydney Desalination Plant — operational information; IPART, 'Indicative bill impact for Sydney Water customers', 19 December 2018
Punjab's aquifers were being drained by rice grown through the hottest, driest weeks of the year. The Punjab Preservation of Subsoil Water Act of 2009, and Haryana's twin law, banned sowing rice nurseries and transplanting before fixed June dates, so that the crop would drink monsoon rain instead of groundwater.
What happened. It worked on water. Modelling published in npj Clean Air in May 2025 found the rate of groundwater decline slowed from 6.23 centimetres a year before 2009 to 3.35 centimetres a year after. But the whole calendar moved with it: peak stubble burning shifted about 15 days later, from around 25 October to around 10 November, into the still, cold weeks when Delhi's air stops clearing.
The catch. The same study modelled daily mean PM2.5 over Delhi rising by roughly 60 micrograms per cubic metre, from about 170 to about 230 — a 36% increase — with severe air quality hours up 92% once aerosol-radiation feedback is included, and attributes around 200 deaths and nearly 10,000 years of life lost per season. It is a modelling study covering 2017 to 2021, not a direct measurement, and late burning has other causes too, including combine harvesting and the short gap before wheat sowing.
Ghude et al., 'The role of atmospheric feedback and groundwater conservation policies in degrading air quality in Delhi', npj Clean Air, 21 May 2025