MANILA - The Department of Environment and Natural Resources (DENR) on Saturday tested the quality of water on several portions of the Manila Bay as the agency set out to rehabilitate the popular sunset viewing spot.

This followed President Rodrigo Duterte's warning on Tuesday for establishments along the bay to follow environmental regulations or face closure, citing the bay's trash problem.

• Duterte tells Manila Bay establishments: Shape up or face closure

Samples were collected from the body of water near Manila's port area, the heavily-populated Baseco compound and the SM Mall of Asia.

An earlier inspection of other water outfalls in the area showed that the Manila Bay's average fecal coliform level was at 330 million most probable number (mpn), 3.3 million times above the standard 100 mpn that is ideal for swimming.

The DENR’s goal is to reduce the coliform level to less than 270 mpn by December 2019, the agency said in a statement.

"Establishments have to put up their own sewage treatment plants (STPs). They cannot discharge their wastewater in the esteros," Environment Sec. Roy Cimatu said.

"We are giving them three months to put up their own STPs," he added.

• Businesses dumping untreated wastewater into Manila Bay: DENR

To improve the water quality, the government may have to relocate some 40,000 informal settler families living along the bay's shores, Cimatu said.

The DENR will also probe if sea vessels docking at the Manila port are dislodging chemicals in the Manila Bay, he said.

The environment department earlier said it would start rehabilitating the Manila Bay within the first month of 2019.

Environment Undersecretary Benny Antiporda earlier said the effort would cost at least P47 billion.

The development came about 3 months after Boracay island underwent a 6-month rehabilitation, and a decade after the Supreme Court mandated several state agencies and local government units to clean-up the Manila Bay.

• Manila Bay checked for compliance with SC cleanup ruling

- with a report from Henry Atuelan, ABS-CBN News