The country now has a resident population of over 3.1 million excluding 700,000 foreigners.

"Even though there is enough clean water for every person, factory, restaurant and so on here in Singapore today, we should never take the supply of clean water for granted," Lim said.

"We need to step up our water conservation efforts, and make sure that every precious drop counts," he added.

Total water consumption by residences and industries amounts to more than 400 million cubic metres (14 billion cubic feet) of water a year, he said.

Authorities would continue to protect scarce water resources from pollution, search for viable sources of water supply and spearhead the national desalination program, Lim said.

"One increasingly important approach is to leverage on advanced technologies to expand our options in water sourcing and water purification," he said.

Singapore purchases a large portion of its water needs from the Malaysia under a contract which expires in 2061.

Authorities here are however keen to reduce reliance on Malaysia as bilateral ties have taken a hit over the last two years.

Kuala Lumpur wants to sell the island republic treated rather than raw water so it could reap more benefits from the deal.