KUALA LUMPUR, March 27 -- Malaysia must shift from voluntary conservation to legally mandating large-scale solutions like industrial water recycling and rainwater harvesting to secure its water supply against increasingly frequent droughts, according to the nation's water regulator.

Charles Santiago, the chairman of the National Water Services Commission (Span), warned that while public conservation efforts are important, they are not enough.

He stressed that stronger policies and enforcement are now essential to force industries to reduce their heavy reliance on treated water, especially as the country faces a dry spell expected to last for several months.

"The time has come for this to be mandated. It cannot remain voluntary," Santia...