A recent round of inspections has found chironomus larvae in 27 water filtration plants across the nation.

The environment ministry said on Tuesday that after conducting special hygiene inspections on some 485 water purification plants, larvae were detected in the “raw water,” the main source of tap water, or in various stages of the purification process at 26 plants.

At the plant located in Yeongwol County, Gangwon Province, one larva was found in a clean water reservoir where treated water is collected.

The ministry clarified, however, that the result does not mean the water in question was contaminated, stressing that a majority of the water where larvae were found were classified as first-class in quality.

The latest water quality inspection came as larvae were found in tap water in Changwon, South Gyeongsang Province, and Suwon, Gyeonggi Province, last month due to poor management of filtration plants.