The state of Oregon has declared a state of emergency after more than 800,000 people in four states were forced to evacuate due to the effects of waterborne illness.
The water system in the city of Portland is also in crisis after a major spill in December left hundreds of residents without drinking water.
The Department of Emergency Management and Public Safety has said the spill, which occurred on the North Fork of the Columbia River, sent more than 300,000 litres of untreated water into the air and contaminated rivers in at least four states.
“We have a crisis in our system right now,” the state said in a statement.
The department said it would use $5 million to help with water and sewer repairs and other upgrades to ensure people in the affected areas are safe.
The spill prompted the closure of the North Cascades National Recreation Area, and residents were asked to leave their homes and businesses.
The governor of Oregon, Kate Brown, ordered the state’s emergency management director, David Leland, to lead an emergency response effort that included the Portland water department, state agencies and emergency management teams.
Mr Leland said that the department would be able to provide “the most effective support” to affected residents, and he thanked the public for their help.
“Portland residents are the first to experience the full extent of the effects when the water becomes unsafe to drink, drink in, drink out,” Mr Leland added.
“People will be left without drinking and we’ll be able at that point to help the water system recover.”
But we will not be able restore our system until we know what’s going on with the water treatment plants.
“In the meantime, I want to thank the public and our emergency managers and all the people who are working around the clock to restore Portland’s public water supply.”
Water shortages and other problems are common across the country, with some regions reporting a shortfall of more than 50 per cent.
The city of Atlanta, which is home to many of the affected residents and has the largest population of African Americans in the US, is also on the verge of being unable to supply water.
On Friday, the city announced that it would be shutting down the water supply for about a quarter of its residents in the Atlanta metropolitan area.