What happened? Timeline of water incident.

A look at events in the city of Dayton and Montgomery County water system crisis Wednesday and Thursday:

WEDNESDAY 4:30-5 p.m.:

Residents and businesses report water outages in northern Montgomery County, affecting thousands of customers in communities that included Butler Twp., Clayton and Harrison Twp.

Calls flood city and county offices and the WHIO and Dayton Daily News newsroom.

7 p.m.

Restaurants along Miller Lane in Butler Twp. begin to close because of the water problems. Customers start a run on bottled water in the area.

7:30 p.m.:

All Dayton and Montgomery County water customers told to conserve as much water as possible and advised to boil tap water before use for health and safety reasons.

9 p.m.:

The Montgomery County Sheriff’s Office asks residents not to call 911 for questions about the water emergency. Sheriff Rob Streck said the Regional Dispatch Center was flooded with calls.

THURSDAY 1:30 a.m.:

Crews discover the water main break that was causing the issues early Thursday morning after about eight hours of searching. The line was in the Great Miami River. The discovery took time because of high river levels and because the distribution system has more than 1,600 miles of pipes for crews to inspect, officials said.

1:30-4 a.m.:

Crews isolate both sides of the transmission pipe that was broken. The main will be repaired when the river level goes down and crews can access it.

8 a.m.:

Dayton City Manager Shelley Dickstein warns city and county customers that the water from their faucets may be rusty, cloudy or milky because of air trapped in the system. Discoloration should go away in the next five to seven days, but in the meantime, citizens should not wash light or white clothing to avoid stains, she said.

Dickstein tells customers to allow their taps to run for at least three minutes before collecting water, which should be boiled for a minimum of one minute before consumption.

8 a.m.:

Water service returned to normal capacity. Water customers no longer asked to reduce consumption.

Water distribution plants are pumping at full capacity, and the area of disruption has been isolated from the distribution system.

8:15 a.m.:

Officials announce a smaller, more targeted boil water advisory and provide separate maps, one for the county users and one for city residents.

Dayton residents told to call 937-333-4905 if they need to determine if they are in an area that is under the boil advisory. Customers should also call that number if they have low or no water pressure.

Montgomery County customers may call 937-781-2688.

10 a.m.

City and county officials tell several local communities, hospitals and institutions they are not in the updated boil advisory area.

4:30 p.m.:

The City of Dayton Department of Water announces samples have been taken from locations throughout the water system for testing for possible contaminants. Testing results are expected by Friday evening; in the meantime the boil advisory remains in effect.

4:30 p.m.:

The city establishes three distribution sites at its recreation centers for customers to pick up Red-B-Gone 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.)

JIM NOELKER / STAFF Montgomery County Water personnel work on a valve under Shourp Mill Road late on Wednesday. A large water main break cut water service to much of the county and most of it was restored by Thursday morning, but continued to require boiling before use.

TY GREENLEES / STAFF An open fire hydrant flows along North Dixie Drive near the Great Miami River as part of a reaction to restore water service from the City of Dayton’s water system on Thursday. A large water main broke late Wednesday and the city was able to bypass the break.