Complex sentence: The municipal water supply for Lac-Mégantic was shut down on the evening of the explosion because of a leak inside the blast zone, requiring trucks carrying drinking water, though the leak was repaired overnight and a precautionary boil-water advisory issued.
Split into simpler sentences: The municipal water supply for Lac-Mégantic was shut down in the evening because of a leak inside the blast zone, requiring trucks carrying drinking water. The leak was repaired overnight and a precautionary boil-water advisory issued.