Ukraine’s Public Health Center has advised residents to keep at least a 72-hour supply of drinking water, recommending 9 liters per person.

Tap water may become unsafe to drink after widespread power outages, even if it appears clear, according to RT.

The center warned that drops in water pressure inside pipes could allow groundwater and sewage to enter the supply system, potentially contaminating drinking water.

It also cautioned that household water filters and boiling may not make the water safe in such cases.