A wastewater leak into the Fish River in Fort Kent, Maine, may have short-term effects on the St. John River, the New Brunswick Department of Health said Wednesday.

The department is posting warning signs at the beach in Saint-Hilaire​ and advising the Village of Baker Brook to take precautions about drinking water.

The Department of Health is also taking water samples at both locations.

The risk from the sewage discharge is low in areas south of Edmundston, the department said.

U.S. officials had already issued a warning about sewage leaking into the St. John River.

The Aroostook Emergency Management Agency issued a public safety announcement Tuesday, warning people not to swim, fish, drink or come into contact with waters downriver from Fort Kent, Maine.

A treatment facility just across the river and the border from Clair, N.B., about 25 kilometres upriver from Edmundston, had failed to contain wastewater during a downpour.

"Basically, what happened was they had pump equipment failure," said Nick Archer, regional director of the Maine Department of Environmental Protection. "Normally, you have two pumps in there, but one of them was out for repair and it was just overwhelmed by the high flow.

"They got a lot of rain all at once up there, like an inch and a half in a short period of time."

The warning shared on social media sites reads: "NO CONTACT ORDER for the Fish River and St John River in Northern Maine from Ft Kent to the Canadian border. "

A warning issued by the Maine Environmental Protection Agency warns people not to swim, drink, fish, or come into contact with waters of the St. John River near Fort Kent. (Facebook)

Border down the middle

The Fish River empties into the St. John River directly across from Canada. The border between the two countries runs down the centre of the St. John River, splitting the body of water in half.

Archer estimates about 50 litres escaped every minute for about seven hours before the leak was stopped at around midnight Tuesday night.

"But they were partially treating it … and they were chlorinating it as they were discharging it," Archer said.

The New Brunswick precautions will remain in effect until the province is sure the situation is resolved.

Samples are being tested by the Environmental Protection Agency and Archer expects results to be within acceptable limits when they come back Thursday morning.

Until then, he said, the warnings about coming into contact with the waters of the St. John River will remain.

The Fish River empties into the St. John River directly across from the Canadian border, about 25 kilometres upriver from Edmundston. (Google Maps)

"We expect because of the chlorination, it should be fine, but we'll have to verify that," he said. "But I would suspect that by the time we pull the samples tonight that everything should be OK."

The spill comes just days before a large muskie fishing tournament is set to start.

"Of course, this would be the week that they have the muskie derby in Fort Kent and they're going to have 500 fishermen going to be up there," said Archer.

"But we think everything is going to be fine."