Multiple discoveries of empty shotgun shells at Western Water reservoirs has prompted the authority to ramp up surveillance across its service areas.
Fearful of the risks to staff who may be inspecting storages, acting chief executive Graham Holt said shells had been found several times in recent months.
He warned that trespassers caught entering a reservoir faced substantial penalties, including on-the-spot fines of up to $1400.
“Our reservoirs are surrounded by fences and clearly marked ‘do not enter’ for a reason: to protect the safety and high quality of our drinking water,” he said.
Mr Holt said dead or dying water birds and other animals could also create health risks through the introduction of microbes into the drinking water system.
“Our customers don’t want people hunting, fishing or swimming in their drinking water and we don’t want anyone to get injured … or worse.”
Western Water carries out regular checks of its reservoirs, including working with Victoria Police when necessary.
Anyone trespassing on the utility’s property is likely to be captured on CCTV.
“Water is a resource shared by the whole community,” Mr Holt said.
“We would ask anyone who sees someone illegally entering a reservoir to contact police.”