Despite reassurances that Hong Kong enjoys a world class water supply, consumers concerned over its purity still opt to buy and install domestic water filters to the taps.
The Consumer Council has received many a public enquiry for advice on such products in the face of lingering concern over the environmental pollution of Hong Kong's water supply.
In yet another test report, the Council focused this time on 8 models of countertop water filters which are bigger in filtration capacity (2,244 L to 4,700 L and above) and price range ($395 to $5,380), too. The samples were sourced from department stores and direct selling companies.
The test offered few new surprises in their performance in the removal of contaminants in tap water - assessed at various points of filtration at 1,000 L, 2,000 L, 4,000 L and 8,000 L.
With some variations, by and large, all samples were able to effectively remove the contaminants as claimed. For testing purposes, 9 types of substances were introduced in tap water, namely, turbidity, E.Coli, chlorine, chloride, fluoride, chloroform, lead, dissolved copper and iron.
A few stood out in that they could even remove the "non-removable" such as dissolved metals.
An important component of water filters is the replaceable filter cartridge which is recommended to be changed every 6 to 24 months. A replacement cartridge could cost from $85 to a hefty $1,390 and some of them are not as widely available at retail outlets as the others.
The cartridge life of the samples were found to range on average from over 7,636 L to over 8,000 L. The test on cartridge life was discontinued once the flow rate fell to one-fourth of the original rate (when the water flow becomes so slow that most consumers are likely to replace the cartridge).
Another factor to consider is the removal capability of the different filtering materials that come with the water-filter, and the contaminants that need to be removed.
For instance, if the target contaminants were chlorine, some organic materials, odour or colour, water filters with cartridge mainly composed of activated carbon may be more likely to be suitable.
On the other hand, if consumers wish to soften water or remove dissolved metals or fluoride, water filters with ion exchange resin are preferable.
The attention of the consumers is also drawn to the provisions in Waterworks Regulation 24 which stipulates that apparatus such as water filters shall not be installed or used without permission of the Water Supplies Department (WSD).
While WSD has no plan to demand customers to remove the water filters installed, it wishes to remind the public of the need for proper maintenance of the water tanks and water pipes in their building.
WSD stressed that if the premises' fresh water plumbing system is properly maintained, there is no need for installation of water filters.
However, if for some reasons consumers still opt to install a water filter, they should ensure - besides proper maintenance of the filter - that provisions will be made to prevent contaminated water backflowing from the filter to the communal water supply system in the event of sudden pressure reversal due to unforeseen breakdown of the communal supply system or the government main supply system.
Consumers are advised to find out in this February issue of CHOICE the various circumstances under which they will be exempted or required to apply for approval from WSD in the installation of water filters.
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