The independent researchers from the subcommittee took water samples from a total of 855 coin operated drinking water vending machines in Bangkok for test.
It found that there were several factors that made drinking water from these vending machines in Bangkok unsafe for drinking.
These factors included unclean body part of vending machines and locations where they were installed.
The subcommittee found that 76.3% of vending machines it examined were installed at inappropriate places such as at places covered by dust from traffic and smokes from exhausted pipes of motor vehicles. The rest was installed near garbage bins and waste water ditches.
It said 55.2% of water vending machines have unclean bodies, 42.9% have unclean valves, 29.4% are rusted, 21.1% are corroded, and 11.2,% are leaked.
It said 93.8% vending machines use tap water to produce drinking water, and only 43.3% of vending machines were given once a month cleaning.
Only 6% of vending machines displayed water quality test, and only 7% had water filter replacement.
The subcommittee then concluded that business operators of drinking water vending machines and concerned government agencies care very little on impact unclean water would have on consumers.
Therefore it suggested consumers to check these factors including the physical condition of vending machines before buying drinking water from these machines.
The survey of the subcommittee has been forwarded to the Ministry of Public Health, Industrial Standards Office and the Consumers Protection Office to work out measures to control water quality in these vending machines.