The production standards of Nongfu Spring mineral water, a popular Chinese brand, are above the national standards for tap water in terms of the amount of potentially harmful minerals, experts said.

Nongfu implements the DB33/383-2005 standard, established by Zhejiang province, the Beijing Times reported on Wednesday.

Experts said that the company should implement standards that are close to the GB5749, the national standards for tap water, in terms of harmful mineral limits.

The GB5749 standard is the basic level for tap water in China, according to the report.

The report found that Zhejiang province's standards are above the national standards in terms of the amount of harmful minerals.

The report also found that a batch of Nongfu Spring mineral water, produced in Guangdong province, also implemented the same standards for Zhejiang province, which violated the regulations of China's health authority.

The regulations state that the mineral water company should apply the standards of the area where the production is based.

The report said that Guangdong province implements stricter standards than Zhejiang for mineral water production.

Nongfu Spring Co declined to comment, the report said.