Ames officials implored residents Friday to do a better job of conserving water after historic flooding caused pipes to break and left the college town of 55,000 without drinking water.

John Dunn, the water and pollution control director in the central Iowa city, said people must adopt "temporary lifestyle changes."

"Water used for any purpose other than essential health and sanitation purposes is hampering our community-wide recovery and extending the amount of time until water is available for drinking," Dunn said. "The use of water for nonessential purposes must stop."

The city was forced to shut down its water system Wednesday after the broken water mains were discovered as a creek and river flooded large swaths of the city about 30 miles north of Des Moines.

By Thursday, residents were allowed to use small amounts of water for showering or flushing toilets, but a boil order remained in effect as officials warned the water may have been contaminated after water towers were drained and pressure dropped. Crews had repaired or isolated the broken water mains and began filling one of the water towers, but it was quickly depleted by usage.

Jean McBreen said she was using only bottled water at home and taking short showers.

"In fact we save water from the showers so if I need to wash some clothes I can do that," said McBreen, who is also the general manager of the Gateway Hotel in Ames.

At the hotel, they took water from the swimming pool to guests' rooms so they could flush toilets.

"I'm hoping the entire town does pull together and conserve because if they have to turn the water off again it's going to be ten times worse," McBreen said. "I just don't think people are taking this seriously enough."

City spokeswoman Susan Gwiasda said all use of water for gardening, lawn care and car washing is prohibited. She said golf courses are on private water systems and not subject to the restrictions.

Anyone using water for nonessential purposes could be fined, she said.

"We want to educate residents first because we believe it's possible some people still don't know, but if we tell them and the problem persists then we would consider taking legal action," Gwiasda said.

The flooding in Ames came after three nights of heavy rain caused creeks and rivers in central Iowa to swell earlier in the week. Hundreds of residents have had to leave their homes in Ames, Des Moines and Colfax, and a 16-year-old girl was killed when a flooded creek swept her car off a road near Des Moines.

Authorities were going door-to-door in a flooded Des Moines neighborhood Friday to make sure homes were safe before allowing residents to return. People had fled Wednesday after Four Mile Creek surged to more than 16 feet, about 4 feet above flood stage. It dropped to about 7 feet Friday.

Jon Davis, Polk County's assistant emergency management coordinator, said officials were making sure there was no structural damage or health concerns, such as mold, water or sewage, and that utilities had been restored.

"The primary concern is the life-safety things and making sure these houses are safe to get back into and get people restored to as normal as possible," he said.

Davis said the evacuation included 145 apartments, 82 mobile homes and 50 houses. No one had returned home early Friday afternoon and Davis said he didn't know how long the inspection process would take.

In Colfax, about 200 homes remained vacant as residents waited for the Skunk River to fall. The river was expected to reach a second crest Friday before receding.

In Ames, officials said it was the worst flooding they could recall. It's believed the water mains broke as the saturated soil shifted, Gwiasda said.

Residents picking up bottled water at the city's four distribution sites said they were going without showers, going to out-of-town relatives to do laundry and using water from dehumidifiers.

"It's pretty serious," said Nadja Hanson. "I guess people take advantage of having water so when they see it coming out of the faucet they think it's OK to use."

Tina Colburn was with her two children, driving through one of the water distribution sites Friday. She said scrimping on water is hard.

"Because water is available I think it's tempting for people to think, just this one time, but if everyone does that it does make a difference," she said.

Colburn, who owns Ge-Angelo's Italian Restaurant, said she is staying open but with a limited menu and not cooking pasta to conserve water.

"It's huge. This is our livelihood," she said.

As residents continue to cope with the water restrictions, the city is keeping a close eye on the forecast, which said there was a chance of more heavy rain later Friday.

"Any additional rain could be a huge problem," said Gwiasda.