BEIJING - China will invest 175 billion yuan ($27.5 billion) before the end of 2015 to ensure safe drinking water in rural areas, a government official said Friday.

Li Guoying, Vice-Minister of Water Resources, made the pledge at an ongoing bi-monthly session of the National People's Congress Standing Committee, citing a State Council report on a five-year plan for improving rural drinking water quality. The report was deliberated by legislators on Thursday.

According to the report, the central government will subsidize 68 percent (about 118.8 billion yuan) of the total investment, while another 22 percent of the funds will be allocated by local governments and 10 percent will be assumed by rural residents, Li said.

Local residents will be charged an average of 54.6 yuan annually, according to the report.

Li said subsidies in eastern and Central China are typically less than those for the country's less developed western areas. In Tibet, for example, the central government will bear all of the costs, Li said.

The number of rural residents who lacked access to safe drinking water dropped by 221 million from 2004 to 2010, Du Ying, vice-minister of the National Development and Reform Commission, said at the Wednesday session.

However, legislators have admitted that improving the quality of drinking water in China has been challenging, particularly in rural areas. As many as 298 million rural residents still lack safe water, according to the report.

China amended its drinking water quality standards in 2006, increasing the number of water quality indices to 106.

"By the end of 2015, the 106 quality indices will be implemented in all provincial capitals and municipalities," Minister of Health Chen Zhu cited the report as saying.