Results from water-quality tests are expected by Friday evening after an overnight water main break and leak under the Great Miami River that left thousands of residents without water or with low water pressure.
Investigators have not yet released the exact cause of the break. The affected line was located just west of the Keowee Street Bridge, a spokesperson for Dayton says.
Water-sampling crews have been testing the water for possible contamination, conducting two rounds of tests approximately 24-hours apart, according to Ohio EPA standards, before they'll issue an official all-clear.
Dayton officials say water service was returned to normal capacity by 8 a.m. Thursday and water customers are no longer being asked to reduce consumption.
But a boil advisory remains in effect for parts of Montgomery County.
Approximately 30,000 service connections, or around 75,000 residents, are in areas affected by the boil advisory.
County officials say it could take until Saturday before the entire boil advisory is lifted.
Search for your address at: www.mcohio.org/water.
County officials say they are so far not seeing an increase in reported health issues related to water contamination.
Montgomery County Health Commissioner Jeff Cooper says the boil advisory is a precaution.
"We're asking all individuals to adhere to it until test results come back confirming that there is no contamination," Cooper says. "It is a nationally recognized best practice to then issue a boil advisory out of an abundance of caution."
He says the risk of illness is low. But particularly sensitive populations may be at greater risk, including infants, people with chronic illness or compromised immune systems, or the elderly.
To boil water for drinking, cooking or oral hygiene, Cooper says, allow the water to come to a rolling boil for at least one minute and allow it to cool before using. Water used for bathing does not need to be boiled.
Montgomery County has updated its list of areas included in the current boil advisory.
The following municipalities are not included: Kettering, Washington Township, Miami Township, Centerville and Moraine.
The county has 34,000 bottles of water on hand is working with community organizations to distribute bottled water at the following additional locations in Dayton:
Christian Life Center, 3489 Little York Road; Happy Corner Church, 7037 N. Union Road; Trotwood Fire Station 72 at 5469 Little Richmond Road.
But officials stress there is a limited amount of bottled water. They're asking that only residents in need take advantage of the bottled water in order to preserve supply for the most vulnerable populations.
"It's important that people only come to get water if they have a medical need or if they do not have access to bottled water on their own," county spokesperson Brianna Wooten says. "We've been working with local community emergency response teams to engage volunteers in the area. Our primary concern right now is to ensure that all the residents have access to clean drinking water while we work to get the system back to capacity."
Click here for an updated map of areas affected by the water outage.
County officials also invite residents to call a helpline to find out whether your address falls under the current boil advisory: 937-781-2688.
Dayton water customers may call 333-4905 to report any issues with water pressure.
The city is offering a special laundry additive to protect laundry from discolored water. Residents will be asked to show identification or a Dayton water bill showing an address in affected areas. The recreation centers are open from 6 a.m. to 9 p.m.: Greater Dayton (2021 W. Third St.) Northwest (1600 Princeton Dr.) Lohrey (2366 Glenarm Ave.)
UPDATE at 10:50 a.m.: City spokesperson Bryan Taulbee says the following Kroger locations will be distributing donated bottled water to those affected by the city's water outage beginning at 11:30 a.m. Thursday:
3520 W. Siebenthaler Ave.
1934 Needmore Rd.
1024 S. Smithville Rd.
UPDATE at 10:00 a.m.: City officials say Dayton's widespread water outage was caused by a leak in pipes under the Great Miami River. Millions of gallons of water were wasted due to the line break. City spokesperson Bryan Taulbee says crews have contained the leak and shut down affected parts of the water system. The exact location of the leak has not been released.
Taulbee says all Dayton customers should still boil water as a precaution.
A map identifying parts of the city affected by the water outage has been posted to the city's website.
The City of Dayton has issued a boil advisory for Montgomery County water customers using the Dayton water system. All residents are instructed to boil water for at least 30 seconds, and to conserve water or avoid using it altogether while the system is under evaluation.
A partial water system outage affecting thousands of customers in northern Dayton and Montgomery County began late Wednesday afternoon.
Crews continue to work in the field to check water valves and 1,600 miles of pipe along major distribution lines and at river crossings for a break. City officials say that this week's heavy rains make discovering a potential leak at a river crossing particularly difficult due to high water levels and swift moving water.
The cities of Oakwood, Huber Heights, Vandalia, Englewood, Miamisburg, and West Carrollton have their own water systems and are not impacted by the outage.