The Republic can draw up to 250 million gallons of water a day, or up to about 60 per cent of its water needs, from the Johor River in Malaysia.
But this is only possible because the Linggiu Reservoir in Johor releases water into the river, preventing seawater from intruding into the river.
Since last year (2014), water levels in the reservoir have been steadily depleting, and have now reached a historic low of 54.5 per cent of its capacity.
A combined image showing the difference in water levels at Linggiu Reservoir in August 2015 (left) and October 2012 (right). PHOTO: PUB
Singapore's national water agency PUB has already had to stop extracting water from the river temporarily 77 times this year.
An El Nino weather phenomenon is also expected to lead to even drier weather than usual for the rest of the year, which will further affect the water supply from the river as well as Singapore's own reservoirs which stores rainwater.
If the situation continues to worsen, Singapore may have to introduce water restrictions, such as banning the use of water jets to clean common areas, said Dr Balakrishnan at a press conference at the reservoir.
He added, however, that water rationing, will not be necessary for now. This is because Singapore has been keeping its own reservoirs full by ramping up water supply from its seawater and used water treatment plants.
"The key point that I want to share is that we are concerned but there is no need for alarm," said Dr Balakrishnan, even as he urged Singaporeans to do their part by using less water.
Several infrastructural projects in the next few years are also expected to help Singapore.
For one, the Johor River will be dammed by a barrage by March next year (2016) to stop seawater intrusion.
Singapore will also finish building another used water treatment plant by next year (2016), and another seawater treatment plant by 2017.
Once those plants are up and running, Singapore will be able to meet up to about 70 per cent of its water needs using treated seawater and used water, which are not affected by the weather, unlike water from the Johor river and captured rainwater.
Treated seawater and used water supplies up to 55 per cent of water needs here now.
Singapore's agreement to obtain water from Malaysia ends in 2061.
By then, the Republic is expected to meet up to 80 per cent of its water needs through treated seawater and used water.
START SAVING WATER NOW!
- DUN LET THE WATER RUN WHILE NOT USING!
- TURN OFF THE WATER WHILE SOAPING DURING SHOWERING!