Water filters will be fitted at all primary and secondary schools built by the government after 2005, but private kindergartens catering to children most at risk from lead-contaminated water will have to help themselves. The Social Welfare Department also promised to install filters at dozens of special education and childcare centres built by the government after 2005 that provide services to children aged under six. "We decided to focus specifically on children aged under six, because we believe this group of children should be priority," said Director of Social Welfare Carol Yip Man-kuen, after a cross-department special meeting on the discovery of excessive lead in school tap water. "Children under six are most at risk from lead," said Permanent Secretary for Education Marion Lai Chan Chi-kuen. "These children are studying in kindergartens … Because kindergartens are privately run, we will not install [filters] for them. But we suggest kindergartens consider buying and installing filters as soon as possible." Chan said the bureau would install filters for about 80 schools built by the government after 2005. There are 1,200 primary and secondary schools across the city. She said contractors had switched to using copper water pipes after 2005 and if plumbers had used lead when fitting them, these pipes were riskier. Education minister Eddie Ng Hak-kim said the filters cost HK$2,000 to HK$4,000, which he believed schools not covered would be able to afford. There are 978 kindergartens across the city catering for about 167,000 children. Yung Hau-heung, the Professional Teachers' Union's early-childhood spokeswoman, took issue with the decision. "It's not about whether kindergartens are privately run. It's about children's safety. They are the future … The government has so much surplus, why can't it spend it on this emergency?" Meanwhile, another public housing estate, Ching Ho Estate Phase 1 in Sheung Shui, was found to have excessive lead in the drinking water of three of its buildings. The 10 problematic water samples contained up to 43 micrograms of lead per litre, over four times the World Health Organisation's safety level. Four children aged seven and eight living in two other public housing estates were found to have excessive lead in their blood - up to 5.43 micrograms of lead per deciliter of blood, slightly above the WHO safety standard of 5mcg/dl.