PUB, the national water agency, thanks Madam Koh Lay Swan for her letter "Take steps to guard against bacteria in water" (Forum Online; Tuesday).

PUB maintains a comprehensive "source-to-tap" monitoring programme for water quality to ensure that the water we supply to our customers is clean and absolutely safe for drinking.

As part of this regime, PUB performs some 400,000 water quality tests a year, testing for more than 300 parameters.

This vastly surpasses the 100 testing parameters specified by the World Health Organisation (WHO) Guidelines for Drinking-Water Quality.

The legionella bacteria is one of the parameters we routinely test for, and which we have, thus far, not detected in our water supply.

Disinfection of potable water before it leaves PUB's water treatment plants will kill all bacteria, including legionella.

Residual chlorine, a disinfectant, is maintained throughout the distribution system to ensure that water remains disinfected while in the distribution network, further protecting against bacterial contamination.

Water supplied by PUB exceeds WHO Guidelines for Drinking-Water Quality and is safe for drinking directly from the tap.

For feedback or assistance, the public can contact PUB's 24-hour call centre at 1800-284-6600.

Lim Mong Hoo
Chief Specialist, Water Quality Office
PUB, The National Water Agency