Officials said sampling found no evidence of harmful bacteria and all samples showed normal water quality.
"Customers can feel confident their water is safe to use like they always would without any need to boil before using for drinking, brushing teeth, making formula, and all other uses," said Philadelphia Water Department Commissioner Randy E. Hayman.
A pump failure shortly before 4 p.m. Sunday created a loss of pressure at a pumping station that serves parts of upper West Philadelphia. This created conditions where there was a risk for contaminated water to enter the water system and customer plumbing.
Customers with questions can go to water.phila.gov or call (215) 685-6300 for more information.