NORTH BATTLEFORD, Sask. -- A drinking water advisory has been lifted for the Saskatchewan city of North Battleford.

The Saskatchewan Water Security Agency lifted the advisory today after getting test results from the city that showed no contamination in the water.

A "process error" last Tuesday led to about 8,000 litres of partially treated water going into clean water at one of the city's filtration plants for six minutes.

The facility was shut down and its main lines were flushed.

Engineers believe the partially treated water remained in the treatment plant, but officials issued the advisory as a precaution.

The city's 14,000 residents were told to boil all water used for drinking, cooking and brushing teeth for at least one minute.

"The safety of our residents and guests is paramount and we thank them all for their co-operation and patience," city manager James Puffalt said in a new release Tuesday.

More than 7,000 residents became sick in 2001 when a parasite called cryptosporidium entered the city's water supply during routine maintenance of a chemical filter.

No one died.