The City of Calgary has completed its review into the cause of a boil water advisory in several northwest communities last month.
Officials say an underground valve chamber was flooded, due to heavy rain, which allowed sediment to enter an underground reservoir.
They say final grading, paving and drainage work was being done at the reservoir at the time, but could not be completed because of the heavy rain, which is why the valve chamber flooded.
The boil water advisory was issued on June 7th and lifted on June 12th.