A boil water advisory that impacted much of the city of Atlanta was lifted Tuesday afternoon after the water supply was found to be safe.

The city’s Department of Watershed Management originally estimated the advisory would continue until at least 6 p.m. to allow time for water analysis to be conducted.

Officials, however, announced the end of the advisory at 1:15 p.m., a little more than 24 hours after pumps at a treatment plant shut off and widespread outages were first reported. Homes, businesses and schools in a large swath of central and south Atlanta were affected, as well as DeKalb County residents who use city of Atlanta water services.

During the advisory, residents were urged to either used bottled water or to boil all water before drinking, cooking, preparing food or brushing their teeth.

MORE: What to do (and what not to do) during a boil water advisory — 7 tips from CDC experts

Several Atlanta businesses, including the Starbucks on Monroe Drive near Piedmont Park, were forced to close Tuesday.

About two dozen schools in the Atlanta Public Schools system affected by the boil advisory got bottled water and prepackaged, ready-to-eat meals.

“Samples taken in these areas confirmed there was no contamination of the public water system,” city officials said in a statement. “Water may be used for all purposes without boiling.”

Shortly after officials lifted the boil water advisory, they held a press conference at the Hemphill Water Treatment Plant, which provides up to 55 percent of the city’s water each day.

WATCH: Officials discuss the boil water advisory

The shut-off at the plant led to a water outage in parts of the city and low pressure for many other Atlanta watershed customers, authorities said.

Water service was restored to customers, though the boil water advisory went into effect as a precaution due to the low pressure.

RELATED: Boil advisory following Atlanta water outage could last until Tuesday

Workers were doing routine maintenance at the northwest Atlanta plant when a process control alarm sounded, a fail-safe that prompted the system shut-down.

It was the first time the city experienced this particular alarm, watershed department Commissioner Kishia Powell told reporters at the press conference.

IN-DEPTH: Atlanta water issues could mean about $250M in economic loss

Crews are planning to assess the system “to keep this from happening again,” she said.

The message for residents, however, was simple: “The Hemphill facility is reliable,” and there is no danger to the public, Powell said.

The Starbucks on Monroe Drive was closed Tuesday morning. JOHN SPINK / JSPINK@AJC.COM

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Atlanta Public Schools officials said the district will follow normal operations Wednedsay.