The latest data from Beijing has revealed that around 90 percent of ground-water in China is polluted, much of it severely, with activists blaming local governments for protecting polluting enterprises.
In a recent survey of water quality in 118 cities across China, 64 percent of cities had "severely polluted" ground-water, Xinhua news agency quoted experts from the ministry of water resources as saying.
Activists say local people suffer from increased rates of various diseases linked to such pollution, and the lack of clean water can affect farming communities' ability to make a living at all.
Sichuan-based rights activist Huang Qi said the lack of access to clean ground water had dire consequences for hundreds of millions of rural residents, who rely on such water both for personal use and for watering the crops.
"Sometimes, these pollution issues turn into mass incidents," Huang said, citing a recent case in the eastern province of Jiangxi. "In Shuangyuan village, there was an incident in which local people smashed up the [polluting] factory."
"I think this is the direct result of inaction on the part of the government, and ties between official and commercial interests that mean that governments actually protect polluting enterprises," he said.
"They often fake the environmental measurements, and take oppressive action against local people."
Only 33 percent of the cities surveyed showed "light" pollution levels, Xinhua said, while the water was measured as "clean" in only three percent of cases.
According to the semi-official China News Service, local governments have begun locking wells in a bid to stop people from using the contaminated water, which is no longer fit to drink.
The report blamed polluting industries and enterprises which were being allowed to continue contaminating the water with no attempt at control from local governments.
Henan-based environmental activist Huo Daishan said polluted drinking water was already being linked to higher rates of cancer, endocrine problems and gastrointestinal diseases.
"There's a problem with the treatment of ground-water for drinking purposes, and it doesn't matter what they do to treat it, if the source isn't clean. All they will do during that process is add new chemicals, and therefore new pollutants," Huo said.
He said many of the polluting factories in his hometown were paper manufacturers, adding that he had begun testing the water himself as early as 2004.
Huo, who has spearheaded a campaign on the heavily polluted Huai river, said a patented biological clean-up system had already yielded strong results on that river.
"After we treated the river water, our statistics show that cancer and congenital endocrine diseases fell by around 90 percent," he said.
"We are hoping to try this method in other locations," he said.
Fujian-based environmental activist Zhang Changjian said that China's ground-water had become contaminated over a long period of time, during which the country's comprehensive set of environmental protection legislation hadn't been enforced at local level.
"There are stringent requirements for waste residues," Zhang said. "They must be stored and transported according to law."
"None of them have been implemented, however," he said.
Sichuan-based environmentalist Yang Yong said that China still lacked specific technical requirements for dealing with waste water that would eventually percolate down into the water table.
"These haven't been set up yet in China," he said. "But it is illegal to allow waste water to seep into the water table with no treatment at all."
Reported by Hai Nan for RFA's Cantonese service, and by Gao Shan for the Mandarin service. Translated and written in English by Luisetta Mudie.