About one third of bottled water sold in Beijing is measured by quality standards set by the producers, the Beijing News reported on Thursday.

A unified national standard for bottled water is lacking in China, and enterprises adopt different standards, including those made by ministries, local governments and the producers.

This leads to a weakening in quality management, according to the report.

Standards made by the producers must be stricter than national or industrial standards, according to regulations, but major producers, including Nestle, refused to publish their standards on the basis of commercial confidentiality, according to the report.

Bottled water quality has become a major health concern among the public after Nongfu Spring, a bottled water supplier in China, was accused of adopting standards issued by Zhejiang province that were not updated to meet national standards.

Zhejiang's health department issued a statement, which says the provincial standard should be abolished so it will not contradict national standards.