Sewage discharged into River Tees
The Environment Agency is warning residents in Stockton not to enter Lustrum Beck after a large discharge of sewage was found in the water.
The sewage has polluted a three-kilometre stretch off water in the beck where it meets the River Tees.
It entered the beck inside a culvert which runs beneath the A177 and railway line in the town near Primrose Hill.
Northumbrian Water stopped the discharge but the clear up will take some time.
The dry weather and lack of rainfall are exacerbating the situation as there is less water to flush the sewage out.
Environment Agency officers are assessing the impact of sewage on wildlife and are urging residents not to play in the water or allow their dogs into the water.
Environment Agency environment management team leader, Graeme Hull, said: "While we have this good weather, children are on holiday, and a Bank Holiday coming up, it is important that they keep away from the beck and avoid playing in it or near it.
"We are currently investigating to see what impact this sewage has had on any wildlife." Alison Brown