Residents near the Waterloo intersection of Caroline and Erb Streets may see some discolouration in their tap water during the next two weeks and if they do, the city says they should not drink it.

The city has moved forward with water main work at that location while the area was closed down for LRT construction.

"The discolouration is largely attributed because of the reversal of the water flow within the system," said Janice Works, communication specialist with the City of Waterloo.

"It causes some of the sediment that might be sitting at the bottom of the pipe to become dislodged and as it gets redistributed causes a discolouration of the water."

Residents within a seven-square kilometre area of the intersection are likely to be affected.

The most affected areas of water discolouration:

South of University Avenue.

East of Westmount Road.

North of the Kitchener-Waterloo border.

West of Conestoga Parkway.

Areas of south of University Avenue, east of Westmount Road, north of the Kitchener-Waterloo border and west of Conestoga Parkway may see water discolouration for the next two weeks. (Courtesy of City of Waterloo)

"The reason why it affects such a large area is because the water that typically that travels through the pipes that are being shut, would feed that entire area of town through a connected system," Works said. "Due to the closure, the water now has to travel around town via an alternate transmission main."

Works said the city saw an opportunity to fix the water main as the LRT construction had already ripped up most of the street, but the water main is not the only thing that will be replaced.

The intersection has been closed since May 16 and will remain closed for another three months. During that time, underground utilities such as the waterline, sanitary waterline and storm waterline, will be also be upgraded and relocated.

Once that work is completed, Avril Fisken of GrandLinq said they will "re-establish the road and begin to build the LRT tracks as well as install new light poles and begin the overhead catenary system."

The city said that the water doesn't pose any harm if you accidentally drink it. Works said if residents see discoloured water, run the tap for 10 minutes. If it's not clear after that, Works said to wait an hour and try again.