Singapore’s tap water still safe to drink: Grace Fu

Minister for Sustainability and the Environment Grace Fu confirmed on October 24 that Singapore’s tap water remains safe for consumption despite ongoing haze conditions. Her assurance followed the widespread circulation of social media videos depicting dark, soot-colored rainwater, which had raised concerns among residents regarding local water safety. In a video recorded at the national water agency Public Utilities Board’s water quality laboratory, Fu addressed the visual discrepancies between raw rainfall and processed municipal supply. Fu explained that rainwater falling during hazy periods tends to be more acidic and contains elevated levels of particles and organic matter. This occurs because precipitation picks up airborne substances as it travels through the atmosphere. To investigate the specific causes of the discoloration, the agency collected water samples on October 17. On that day, the Pollutant Standards Index stood at 193, a range indicating unhealthy air quality. The samples included rainwater gathered from Kranji and Ulu Pandan, runoff from Yew Tee, and standard tap water. Visual aids presented in the minister’s video detailed the chemical differences between these samples. Rainwater collected on October 17 registered a pH level of 5.7. For comparison, rainwater from moderate haze days measured 6.6, normal day rainwater measured 6.8, and treated water measured 7.8. Turbidity levels, measured in nephelometric turbidity units, were also higher in the hazy sample. The October 17 rainwater recorded 5.7 units, whereas moderate haze rainwater recorded 3.6, normal rainwater recorded 2.1, and treated water recorded just 0.21. Higher turbidity values indicate cloudier water. Despite these findings in raw samples, Fu emphasized that water stored in Singapore’s reservoirs undergoes multiple treatment stages designed to eliminate dirt, microscopic particles, and other impurities. She stated that current treatment processes can filter out particles up to one hundred times smaller than PM2.5. PM2.5 denotes fine particulate matter with diameters of 2.5 micrometres or less, which typically dominates the air during haze episodes. Consequently, the agency expects all such haze particles to be removed before water reaches consumers. As a precautionary measure, the utility company increased the frequency of water quality checks across the nation during the haze period. Testing results indicated no unusual alterations in the quality of the treated water supply. Fu advised the public against using unprocessed rainwater for drinking, cooking, or personal hygiene, noting that the extent of discoloration depends on whether the water is collected directly from the sky or via surface runoff. While the appearance of blackish rainwater may appear alarming, the minister concluded that the tap water remains clean and safe for daily use.