On a stretch of reclaimed land in Tuas, a water factory is taking shape. Singapore's third desalination plant, expected to be ready later this year, is one of several infrastructure projects in the pipeline to ensure a nation surrounded by water has enough to meet its needs.
At two older plants nearby, sea water is already filtered and passed through membranes to remove dissolved salts and minerals, as part of a process to get water fit to drink.
Singapore's fourth national tap - desalinated water - is part of a long, and often little-heard, story of this nation's quest for self-sufficiency in man's most valuable resource.
Tap one: Catchment areas were expanded, and new storm drains and reservoirs built over the years.
Tap two: Imported water, made possible through two agreements with Malaysia that Singapore leaders made sure were guaranteed in the 1965 Separation Agreement.
Tap three: Newater - high-grade recycled water - launched in 2003 with two plants in Bedok and Kranji. Three more have since opened.
Tap four was turned on in 2005, with the opening of SingSpring desalination plant in Tuas made possible by advances in technology.
Today, Newater meets up to 40 per cent of Singapore's water demand and desalination 25 per cent.
And plans are under way to boost capacity so both meet 55 per cent and 30 per cent of water needs respectively by 2060, before the second water agreement expires.
But the cost of operating and maintaining the water system has risen over the years, prompting the Government to review the price of water - and raise it by 30 per cent over two phases, this July and next.
It is the first price hike in 17 years.
The previous hike, phased in from 1997 to 2000, saw tariffs go up by 20 per cent to 100 per cent on a scale depending on usage.
Costs have gone up sharply since then. Last month, national water agency PUB said it cost about $500 million to run the system in 2000. By 2015, this had risen to $1.3 billion. This includes collecting used water, treating water, producing Newater and desalination, as well as maintaining water pipelines.
WHAT PRICE, WATER?
As Finance Minister Heng Swee Keat and Environment and Water Resources Minister Masagos Zulkifli reminded Parliament this month, the cornerstone of Singapore's water policy is the pricing of water on sound economic principles to reflect what is called its Long Run Marginal Cost (LRMC).
This reflects the cost of supplying the next available drop of water, which is likely to come from Newater and desalination plants, and enabling investments in such plants.
Mr Masagos noted the first-year price of the first desalination plant, SingSpring, which opened in 2005, was 78 cents per cubic m. By comparison, the first-year price of the latest plant in Marina East, set to open in 2020, is $1.08 per cubic m - an increase of some 40 per cent.
"It is only through right pricing that we can have everyone valuing water as a strategic resource and consciously conserving it," he said.
Understandably, the price hike generated much discussion on the ground, prompting ministers to point out that, in reality, most businesses will see a rise of less than $1 a day, and for most households, a jump of less than $12 a month.
And at the start of a month-long water conservation campaign, Deputy Prime Minister Teo Chee Hean pointed out that a 330ml bottle of water costing $1 from a supermarket will pay for 1,000 bottles of clean water from the tap after the full price rise.
It is a price comparable to that in major cities in developed countries with large rivers to draw from. It is also a price that makes possible considerable investments in the future.
The years from 2000 to 2015 saw $7 billion invested in water infrastructure - or $430 million a year. PUB expects this to almost double to $800 million every year from this year to 2021, to fund major investments in strengthening the third and fourth taps, and build and repair pipes and pumps. There are also higher costs of manpower, materials and chemicals, and more difficult and expensive developments needed, such as having to dig deeper underground to lay pipelines.
Less noticed but equally crucial to water management are several intangible aspects of Singapore's approach to water.
One is minimising leakage. Only 5 per cent of treated water in Singapore is lost through leakages - a figure bested by Tokyo but ahead of the United States and Hong Kong.
Some developing cities can lose as much as 60 per cent of their water through leaks, notes water expert Asit Biswas at the National University of Singapore's Lee Kuan Yew School of Public Policy.
Another not-so-visible reward of Singapore's meticulous water planning is that two-thirds of the country serves as a catchment area for drinking water supply, among the highest in the world.
Furthermore, the price of water enables not just the production and delivery of potable water, but also the treatment of sewage and industrial waste water so it can safely go back into the environment.
One fact not often appreciated is that Singapore has separate systems for drainage and sewage, a more efficient set-up than a system in which everything flows into sewage, such as in London.
PUB said sudden surges of water caused by stormwater flowing through a combined system will reduce the effectiveness of the microorganisms used for biological treatment in water reclamation plants.
A Deep Tunnel Sewerage System is also being built to collect, treat, reclaim and dispose of used water from industries, homes and businesses, that will feed into a water reclamation plant and Newater factory, and should be ready by 2025.
This determination to make every last drop of water matter has seen other countries wanting to learn from Singapore's experience, and spawned opportunities for home-grown water companies.
In California, water managers are adapting a technology refined in Singapore - the membrane bioreactor - to treat industrial waste water and use the treated water to directly replenish the water-stressed state's freshwater aquifers instead of discharging it into the sea.
They are doing this with the help of international environmental engineering company CH2M, which is designing the new Tuas Water Reclamation Plant. The membrane bioreactor combines filtration with biological breakdown of organic matter by microorganisms.
Said Mr Peter Nicol, CH2M's senior vice-president and global director of water: "Singapore has identified the areas it would like to see improvement in, and put challenges out to the private sector to come and work with them aggressively on piloting technologies full-scale. It then shares that information with the global water market."
Even as Singapore builds a robust, diversified water supply across its national taps, a key complementary strategy has been to drive home the importance of conserving water. Public education has seen results: Between 2003 and 2015, households cut their water use per person per day from 165 litres to 151 litres. The PUB's long-term goal is to see this lowered to 140 litres by 2030.
Observers say there are several cities from whose books Singapore could take a leaf from in the "softer" side of water conservation. In Sao Paulo, which experienced a drought from 2014 to 2015, water use fell 30 per cent in a year, helped by discounts given to people who reduced consumption. Prof Biswas says Singapore could benefit from such financial incentives for reducing water use. "Sao Paulo is growing much faster than Singapore," he says. "The government went to the people saying: 'Look, we cannot solve the problem until you change your behaviour.' People realised water was becoming scarce and they had to do something," he said.
Namibia's capital Windhoek has another lesson. Situated in an arid climate with frequent droughts, it has been treating its waste water and putting it directly back into taps, because it has no other choice.
There are other ways to encourage people to value water more and use less of it, such as having multiple tiers in water charging.
Singapore has a two-tier system of domestic potable water tariffs, with one price per cubic m for the first 40 cubic m and a higher price for anything beyond. PUB says the 40 cubic m limit meets most needs as 94 per cent of households consume less than that volume every month.
Therein lies the problem, says Prof Biswas, as most people won't feel the pain of the more expensive tier. He feels the first tier should be much lower in consumption, closer to the reasonable water use expected of an average household, and usage beyond that split into three more tiers to penalise high water usage. "You can use more water, but you have to pay more for it. Society does not owe you as much water as you want," he says.
However, PUB said properly multi-tiering the water tariff would require a complicated system to accurately determine the number of people per household and how it changes over time. It would also mean applying different thresholds for different household sizes and this would raise costs, it added.
One thing is clear: Singapore should not go the way of others and underprice water. Observers cite how India, for instance, has difficulty developing water infrastructure, or Qatar has a hard time cutting consumption as water is free for locals.
Mr Subbu Kanakasabapathy, CH2M's regional managing director for the Asia-Pacific, says this has resulted in the poor paying more for water in India than if it were priced properly, because they are forced to buy water at a high price from private water trucks.
The unreliable water supply also compromises health.
Which is why Prof Biswas feels if Singapore adds a fifth national tap, it should be a very different kind of tap from the first four - to reduce demand for water, rather than increasing supply as civilisations have been doing for centuries. It can be done, as others have shown.
The World Health Organisation says only 50 to 100 litres of water are needed per person per day for basic needs. If Singapore cuts its per capita daily consumption from the current 148 litres to 100 litres, it would save 240 million litres every day for a population of five million.
"Technology is not going to solve our problems as it did in the past. The next breakthrough has to come from the behavioural sciences. The water industry needs more psychologists and behavioural economists," said Prof Biswas. "We have to try everything."
In a primer on water in the Singapore Chronicles series published last year, PUB chairman Tan Gee Paw notes that two big challenges of water management Singapore is likely to face in future are climate change and complacency.
"In less than a lifetime, Singapore's efforts at water management have come a long way," he wrote. "It is the enduring legacy of a small, dry island that such efforts remain unceasing, unrelenting and ever more vigilant."
The attention water has had in the headlines in recent weeks is thus a reminder that Singapore's water journey is far from over, even as it works towards self-sufficiency before the end of the water agreement in 2061.