More than half of the groundwater monitored in the country's major cities failed to meet standards for drinking, a report by the country's land watchdog said.

Groundwater at 57.2 percent of the 4,110 monitoring stations in 182 cities was classified as bad, meaning people's health could be harmed, according to a Ministry of Land and Resources report released on Wednesday.

The quality of groundwater in most northern and eastern parts of China was worse last year than in 2009, the report said, without stating locations. The level of groundwater had also dropped as a result of overexploitation.

Household sewage, industrial pollution and overuse of fertilizers and pesticides had led to further deterioration of groundwater, Ma Chaode, former director of the World Wide Fund For Nature's freshwater program in China, told China Daily.

Pollution of groundwater and water in rivers and lakes had reached a serious level, he said.

Zhang Zhaoji, a researcher with the Chinese Academy of Geological Sciences, agreed. He said protecting groundwater in the northern parts of China was more challenging than in the south.

"In the northern parts, pollution of groundwater is widespread and the situation is getting worse," Zhang told the 21st Century Business Herald.

Earlier statistics released by the State Council, the country's Cabinet, showed the North China may be more affected by deteriorating groundwater quality because there are fewer rivers and lakes in the north.

In North China, about 65 percent of water supplies for residential use comes from groundwater.

More than 400 out of the country's 657 cities use groundwater as major source of drinking water.