Mainland experts are alarmed at the poor quality of tap water in major cities, saying a lack of government action and inadequate public attention has made widespread contamination problems even worse.
Their warnings, which shed light on a rarely talked about issue, come just days after a revised guideline on drinking water quality was put into effect across the mainland this month.
Government officials have hailed the new guideline, which expands the number of parameters monitored from 35 to 106, with particular focus on the measurement of heavy metals and organic pollutants, as a major step towards the ultimate goal of residents being able to drink water directly from their taps.
But environmental and medical experts have cautioned against such optimism, citing a lack of government funding when it comes to improving outdated water treatment plants.
They warn that most drinking water processing facilities on the mainland cannot meet the stricter standards, despite being given a grace period of seven years after the guideline was first introduced in 2006.
Even if the new guideline can be implemented at some time in the future, they say it will still be difficult to ensure that tap water piped into homes is safe to drink because of contamination from chemicals used in the pipes connecting treatment plants and homes and from toxic organic compounds that are soluble and difficult to remove.