Some 85 per cent of the population will be flushing the toilet with seawater by next year as part of a drive to save fresh water, the water-supplies chief pledged. Already 80 per cent of Hongkongers flush with seawater and the supply will be extended to areas including parts of Pok Fu Lam, Yuen Long and Tin Shui Wai, director of water supplies Enoch Lam Tin-sing told lawmakers yesterday. The long-term aim is to extend it to 90 per cent of the population, using waste water in some areas. Lam was responding to criticism from unionist lawmaker Wong Kwok-hing, who slammed the government for warning that water rates might rise while failing to demonstrate a determination to cut water usage. "The government warned of the possibility of increasing water tariffs. But it didn't say how the government would save water by reducing the amount of freshwater used for flushing toilets," Wong said, referring to Financial Secretary John Tsang Chun-wah's February budget. Lam told a special meeting of the Legislative Council's Finance Committee that 6.33 million people would be flushing with seawater by next year. "If waste water is also used for flushing, the coverage can be enlarged to 90 per cent of the population," he said, "As for remote districts and the Peak, we need to study its feasibility further." A department spokesman said waste water could be used in Sheung Shui and Fanling but no timetable was available. An average of 762,560 cubic metres of seawater was used for flushing each day last year, the department said, enough to fill 305 Olympic-sized swimming pools. Lam said the department would also consider extending a water-saving campaign it began last month after receiving 60,000 applications to take part, double the original target. Participants are given a device to control the flow of water from taps and a target of saving 10 litres per day. The department was also working with hotels on water-saving guidelines, Lam said. At the same meeting, Secretary for Development Paul Chan Mo-po said the government would consult lawmakers if it planned to raise water charges. While Hongkongers pay heavily subsidised rates for fresh water - most of which is sourced from the mainland - seawater is provided free. Seawater flushing was first introduced in the 1950s amid concern about a fresh water shortage.