We thank Mr Wong Chee Meng for his letter (How did PUB conduct tests to ensure water safety? April 23).

PUB takes water quality in Singapore very seriously. We have a comprehensive and robust sampling and monitoring system to ensure our tap water is clean, wholesome and safe for direct consumption.

Water quality is closely monitored and tested at every step - from the source, including reservoirs and seawater, to the treatment process (including membrane systems) in the waterworks and desalination plants, and the water supply in the distribution network.

Water samples from consumers' taps are also tested daily.

All water produced by our waterworks and plants is tested to ensure that it meets our stringent water quality requirements before being supplied to consumers.

Water, including those from Tuaspring Desalination Plant, that does not fulfil our water quality requirements will be rejected and not supplied.

Singapore's water is thus perfectly safe for drinking directly from the tap without any further filtering or treatment.

Singapore's tap water has consistently passed the World Health Organisation (WHO) Guidelines for Drinking-Water Quality. We conduct over 400,000 water quality tests annually on more than 300 parameters, surpassing some 100 parameters specified by the WHO.

Lim Mong Hoo

Director, Water Quality Department,

PUB, Singapore's National Water Agency