The South Tahoe Public Utility District says a boil water alert was issued for the North Upper Truckee neighborhood for all streets off North Upper Truckee, between Highway 50 and Zuni Drive.
Officials said the Chiapa neighborhood is included in the order as well.
The boil water advisory was issued out of an abundance of caution and is expected to be resolved by Thursday evening or Friday morning.
After a routine water tank cleaning last Friday, the tank was refilled and chlorinated. The chlorine residual was lower than required for tank disinfection and the water tank was isolated from the system over the weekend.
Officials said a faulty isolation valve did not completely close allowed approximately 100,000 gallons of water to drain into the distribution system over the weekend.
Officials are testing the water throughout the impacted area and will notify customers once the boil water advisory has been lifted.
Households should only use tap water that's been boiled vigorously for one minute or bottled water for drinking and cooking purposes to avoid illness.
Tap water may still be used for bathing, hand washing and laundry.
