Chris Weller: Singapore has come up with an ingenious way to save water

It rains a lot in Singapore — approximately 94 inches a year.

But rather than let that water evaporate wastefully on the streets and sidewalks, Singapore sets a standard the rest of the world would be smart to adopt: The city-state soaks up water like a giant sponge.

By recycling the rainwater through built-in runoff capture systems, Singapore can reduce both the costs of water purification and its environmental impact.

Scientists believe our global water crisis is only getting worse. By 2025, two-thirds of the world population will struggle to find water and 1.8 billion people won't have any at all.

Using recycled water could be a solution.

In China, roughly a dozen cities have started brainstorming what that might look like — turning so-called "grey infrastructure" into green infrastructure by adding the ability to store rainwater. Mostly, these plans address rampant flooding that could quickly clear small towns and villages.

But no country has such a robust system already in place as Singapore, where half the land area (update: more than half by now) is equipped to capture rainwater in gutters, barrels, tanks, and reservoirs.

The most sophisticated of those systems is at the Changi Airport. Between 28 and 33% of all water used in the airport comes from captured rainwater, which is stored in two reservoirs.

One reservoir balances the flow of water when tides are high, while the other collects runoffs from runways and green areas.

Each year, the infrastructure saves the airport more than $275,000 for non-potable uses, like flushing toilets and performing firefighting drills.

Scattered elsewhere around Singapore are capture systems on top of high-rise apartment buildings, in which 86% of citizens call home.

Rooftop harvesting equipment saves roughly 14 cents per cubic meter of water over relying on nearby rivers and streams or purifying water that flows through soil.

When the rainwater isn't collecting on roofs, it's soaking into the urban environment at-large.

There's a fascinating backstory to Singapore's urban sponge scheme.

In the mid 1980s, Singapore's crisis of clean water got so bad that the country had no choice but to get creative. While it had plenty of rainwater, it had no way of capturing it. Water would mix with soil and other contaminants making it unfit for use. So, in 1986 Singapore took the first step in water conservation, creating the the Sungei Seletar-Bedok water scheme.

The existing Seletar Reservoir was dammed to divide it in half. The separation essentially allowed polluted runoff water to collect elsewhere, in the Bedok reservoir, which was designed for treatment, while the cleaner part of the storm water collected in newly created Lower Seletar Reservoir.

In the decades since, Singapore has transformed its culture into one that prizes its ability to reuse rainwater.

Even residents in the outskirts have transformed their homes into capture systems as a means of watering their lawns or, with the right treatment, staying hydrated.

If other countries want to have any hope of avoiding a water crisis, they'll need to get as creative as Singapore.