FORT MYERS, Fla. — Engineers stopped releasing water from Lake Okeechobee on Saturday, confident that they had lowered levels enough to keep the dike and the towns around it safe as Hurricane Irma swept into southern Florida.

But the dike, built seven decades ago and named for Herbert Hoover, was not the only major piece of Florida infrastructure that had officials concerned as the hurricane approached. Airports, sewage treatment plants, flood control systems and other facilities could be overrun by heavy rains or flooding from storm surge, as Irma’s winds amass ocean water and push it ashore.

The impacts of climate change — especially sea level rise, which is already bringing more tidal flooding in Miami Beach — could make matters worse, as any storm surge from Irma would be on top of an already higher baseline.

And Florida, like every state in an era of tightening budgets, has deferred costly maintenance on much of its infrastructure, said Addie Javed, a former president of the Florida section of the American Society of Civil Engineers.

“Deferred maintenance is the biggest problem; later or sooner you’re going to be paying for that,” he said. “You want to make sure that your infrastructure is in top shape when a disaster like this happens.”

As South Florida’s population has swelled in recent decades, its roads, water and sewage treatment plants and other facilities have struggled to keep pace. Much of the state’s infrastructure is now nearing the end of its useful life, so maintenance is even more important, Mr. Javed said.

In its latest annual report, which Mr. Javed helped prepare, the engineering society gave the state an overall grade of C for its infrastructure, better than the national grade of D-plus. Some elements, including airports, ports and bridges, earned high marks.

But others, including water and sewage treatment plants, were poorly rated. The federal Environmental Protection Agency estimated last year that $17 billion would be needed over the next two decades just to maintain Florida’s existing drinking water systems.

Waterworks and sewage treatment plants can be especially vulnerable to freshwater flooding or storm surge, as they are often sited on or close to rivers or the ocean. Hurricane Harvey was a reminder of that vulnerability: Beaumont, Tex., had no drinking water for several days after its plant was knocked out of service by flooding along the adjacent Neches River, the source of the city’s water.

Mr. Javed said most of Florida’s water comes from wells, so flooding should not be a concern. Sewage treatment plants are another story, however. While many have special valves designed to prevent too much storm water from entering the system, they can be overwhelmed in severe storms, and untreated sewage can end up in waterways.

As for roads, of special concern is the Overseas Highway, 115 miles of causeways and bridges between Miami and Key West. While much of the road is elevated on pilings, it can be damaged in severe storms, as it was in 1998 during Hurricane Georges. Irma is expected to pass over it early Sunday.

There are also low-lying causeways in Tampa Bay that may be susceptible to storm surge.

The state’s energy infrastructure is privately owned, and Florida Power and Light, which operates the state’s four nuclear reactors at two sites on the Atlantic coast, said the reactors would be safely shut down as winds reached hurricane strength. But the company also warned that Irma’s winds would likely wreak havoc with electrical distribution lines, and that as many as 4.1 million homes and businesses could lose power.

Lake Okeechobee was historically the source of water for the Everglades, although flows from the lake are now controlled and serve several purposes, including agriculture. The 143-mile-long earthen dike was built in the 1930s, after two hurricanes in the decade before brought catastrophic floods, one of which killed 2,000 people.

Mr. Javed said the dike was a good example of Florida’s maintenance problem. The United States Army Corps of Engineers, which controls the dike, has been working on repairs since 2001, and the project is expected to take another eight years. The cost so far is in the hundreds of millions of dollars.

Governor Scott cited those repairs when he ordered the evacuation of seven towns near the lake, Florida’s largest. The order was precautionary, and the Army Corps had assured the governor and the public that it would remain intact even if high winds pushed water over it.

To make room for the expected rainfall, the Army Corps had lowered the level of Lake Okeechobee by releasing water into canals that drain the lake.

Even if the dike functions well during Irma, Mr. Javed said, there might be some spillover from several areas of the dike where work is being done.

But the assurances from the Army Corps were enough for Gail Rushing, a caterer in the sugar-cane farming town of Clewiston, one of the towns affected by the evacuation order.

On Friday, before the pumping was halted, Ms. Rushing said she would ignore the order and stay. She lives only about a dozen blocks from the dike, and while she was concerned, she said, “I do have confidence” in the engineers and the pumps.