The 7:30 p.m. synchronized flushing was to help prevent pipes from bursting after local officials started rationing water because of a drought, Africa Review reported.
"This is done to prevent any sewer blockages as we anticipate longer periods without water in the reticulation system," city council spokeswoman Nesisa Mpofu said, who added the big flush was to be in addition to other flushes during the day.
The communal flushings are expected every three days during the drought. Two of the city's five supply reservoirs have emptied and two others could go dry before the region's usual November rains.
"Water rationing may be extended to 92-hour periods. The situation is very serious," Mpofu said.
The situation wasn't sitting well with some. A blogger on the Zimbabwean activists website Kubatana.net wrote: "People who flush together, make revolution together? Only in Zimbabwe ... how much [expletive] from this incompetent government will we continue to tolerate?"