The Water Security Agency has issued a "Do Not Use" notice for a number of residents in the Aspen Ridge Neighbourhood.

“I want to stress that residential water has tested clean, but hydrocarbons have been detected in some hydrants in the area,” says Angela Gardiner, Acting General Manager of Transportation and Utilities, in a news release issued Wednesday night.

“For this reason – the hydrocarbons in some hydrants – the WSA has ordered the water supply can’t be used for personal contact at 19 addresses in Aspen Ridge.”

The City cannot be certain how the hydrocarbons got there, according to Gardiner. She says it's an ongoing investigation.

Temporary water supplies for drinking, cooking and hand washing are being provided until a longer-term solution can be implemented.

The WSA recommended the precaution until the investigation is completed, even though the residential supply tested safe.

“What we know is the hydrocarbons are not detectable at all in testing because the levels are so low – but they are visibly present on inspection.”

The city says affected residents are able to use a City leisure facility for showering. They can also to reach out to friends and family for bathing needs.

The order does not affect laundry and flushing toilets – those uses are allowed.

The city says staff have met with the affected residents to answer any questions.