Atlanta’s Department of Watershed Management issued a boil water advisory on Friday for residents and businesses in downtown Atlanta and nearby neighborhoods after an internal power failure at the Hemphill Water Treatment Plant.

Officials said the alert was issued out of an abundance of caution, and a map of the affected area shows it stretches from Vine City to Grant Park, with Mechanicsville, parts of Inman Park, Peoplestown and Pittsburgh also within range.

Power had been restored at the plant in an update just after 11:30 a.m., but officials did not give a specific timeline for when the advisory would be lifted. They said it would stay in place until sampling protocols are completed.

The advisory matters because it affects homes and businesses in a dense part of the city on Friday, when people are moving through downtown and relying on water service for work, meals and daily routines. Officials said anyone in the impacted area who experienced outages or low pressure should boil water for at least a minute past a rolling boil before using it, and they encouraged residents and businesses to drink bottled water until the alert is lifted.

The power failure at the Hemphill Water Treatment Plant is the reason the boil water advisory exists, but the unresolved piece is how long it will take for testing to clear the system. Until that happens, the map remains the clearest guide to who needs to treat tap water as unsafe to use without boiling.