Arms outstretched and neck deep in water, a woman was shown to be swimming in what appeared to be Hong Kong’s High Island Reservoir in a photo circulated on social media on Thursday.

She was part of a group of three women and two men who were photographed dressed in outdoor gear. One of the photos showed two women swimming while clothed, while four other photos showed people posing at the edge of the water. It is unclear when the photos were taken.

woman swimming high island reservoir
Photo: 山野龍咁威 via Facebook.

The photos were first publicised on Facebook on Wednesday evening, and online commenters quickly condemned the hikers’ behaviour and raised doubts about public hygiene.

One commenter wrote, “They must have known this was illegal, report them to the police!”

“Maybe later someone will let loose some piranhas too,” wrote another commenter.

Reservoir swimming
Photo: 山野龍咁威 via Facebook.

The Water Supplies Department told HKFP that it will look into the incident and take legal action if necessary.

According to the Waterworks Ordinance, any person who enters, bathes or washes in a reservoir shall be liable to a HK$50,000 fine and up to 2 years’ imprisonment.

hikers swimming reservoir
Photo: 山野龍咁威 via Facebook.

The Water Supplies Department also said it would step up patrols around the reservoir, and urged the public to avoid contaminating the water source.

The High Island Reservoir in Sai Kung is the city’s largest reservoir, with a capacity of up to 280 million cubic metres.

High Island Reservoir
High Island Reservoir. Photo: GovHK

Some of Hong Kong’s reservoirs were affected by the heatwave in May. According to the Water Services Department, the High Island Reservoir’s water reserves went down by about 2 million cubic metres during the first two weeks of last month.

Holmes Chan is a reporter at Hong Kong Free Press. He covers local news with a focus on law, politics, and social movements. He studied law and literature at the University of Hong Kong.