09/20/2012 08:11 EDT | Updated 11/20/2012 05:12 EST

B.C. city famous for tap water now advised to boil it

The residents of Greenwood, B.C. — which touts its tap water as "the best in the world" — can once again use the outflow from their faucets, but until further notice, they are to boil it before drinking.

On Monday evening, it was discovered that the city's reservoir lock had been tampered with. The mayor immediately declared a state of emergency and no one was allowed to consume the water or use it for anything other than flushing toilets.

That ban has been downgraded to a boil-water advisory as the city waits for test results from the Interior Health Authority to determine if the water has been contaminated. Those results are expected by Friday.

Greenwood won the title of "World's Best Municipal Water" at the 22nd annual International Water Tasting competition in West Virginia last winter. The community also bills itself as the smallest city in Canada.

City flushes system, trucks in water

As the city waits for the test results, crews have drained and filled the water reservoir several times and are flushing the entire water system.

The city is also trucking in water and residents can fill their own containers between 8 a.m. and 4 p.m. PT.

Free bottled water is available from Greenwood city hall.