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.

Vice-Minister of Water Resources Li Guoying 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, or 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.

In the next three years, the central government's allocation will be first used to guarantee the operation of the drinking water projects for rural areas, Li said.

Meanwhile, efforts should be made to protect water sources by reducing and optimizing the use of fertilizers and pesticides in agriculture, strengthening rural pollution treatment and water environment treatment, as well as boosting rural ecosystem restoration, said Li.

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

Also by 2015, nearly 80 percent of the rural population will have access to safe drinking water through centralized water supply facilities, Du said.

China should also deepen its reform of water prices nationwide and further promote the progressive pricing scheme for water use, in order to realize the goal set for the next three years, said Du Ying.

The water price should be meted out in accordance with local economic development, water supply costs and residents' income, said Du.

The one-month water rate for each household should not exceed 1 to 2 percent of the family income, said Du, adding that the current water rate is far below the percentage.

Li said the per capita possession of water resources is 2,100 cubic meters, or just 28 percent of the world's water supply, and surface water pollution has aggravated the country's water supply.

Many areas have to exploit groundwater. At present, groundwater exploitation has reached 110 billion cubic meters, close to the warning limit of 123 billion cubic meters, Li said.

To avoid the emergence of severe ecological problems that Li has warned about, the State Council has approved plans for the development of national water resources and aims to control exploitation within 93.7 billion cubic meters by 2030.

The Ministry of Water Resources also vowed to take measures to limit total groundwater exploitation within 104 billion cubic meters by 2015, Li added.