Should the clear well become too full, water spills into the box and then into the drain. But when last week’s rains came, the storm water pipe became engorged and water went up into the weir box where a flap designed only to open if water was being discharged into the pipe became stuck, allowing storm water, and the debris it contained, to enter the well. The state was notified, and the boil-water advisory was issued and testing began. It continued: “Since the precautionary boil-water advisory was put in place, city staff have been working around the clock in accordance with state guidelines to get the Poway water system back online. The city has given out hundreds of thousands of bottles of water to residents since the advisory went into effect Saturday night.

Source: Los Angeles Times December 05, 2019 06:00 UTC