Vital Central Valley flood control levees are poorly maintained, California watchdog finds

With California bracing for a wet winter, the state auditor warns that nearly a third of local agencies maintaining vital flood control levees in parts of the Central Valley have been performing “unacceptable routine maintenance” — some of them, for years.

The audit says the state’s Department of Water Resources “has not followed state law requiring it to take over the maintenance of levees” when local agencies fail to do so — and urged it to start.

But state water managers at the department pushed back, saying the audit “portrays a fundamental lack of understanding of the complexities of flood management” and draws too direct a link between routine maintenance and flood risk.

Taking over maintenance can cost tens of millions of dollars up front “that must be weighed against other investments that may yield greater risk-reduction benefits,” the department said in a letter responding to the audit.

Others question whether the state is up to the job. “They can’t even take care of what they have now, and they want them to take over everybody else?” said Tom Engler with MBK Engineers, who works as the district engineer for a dozen Northern California reclamation districts responsible for levee systems.

The audit warns that inadequate maintenance increases the risk that these aging, earthen embankments fail, endangering more than a quarter-million people, 133,000 buildings worth nearly $40 billion dollars, as well as hundreds of thousands of acres of farmland . Historically underserved communities and socially vulnerable people are especially at risk .

California oversees 1,600 miles of levees and other flood control structures on the main stems and certain tributaries of the Sacramento and San Joaquin rivers, as part of the State Plan of Flood Control.

But that responsibility is layered , built on federal requirements and topped by state oversight. Sandwiched in between are the levee and reclamation districts, private landowners and local governments that conduct maintenance under agreements with the state.

Some note that, in fact, the state already manages some of the levee systems in Butte and Sutter counties that are on the auditor’s list of local agencies performing unacceptable levels of maintenance .

“Tell me how that makes sense,” said Engler. “(I)t would take a lot more people, manpower and equipment to get it all done.”

Department of Water Resources spokesman Jason Ince said this highlights the audit’s overreliance on maintenance inspections to assess risk. According to Ince, of the three levee systems under the responsibility of DWR’s Sutter Maintenance Yard on the list:

The department told the state auditor that levee risk depends on the threat, the levee’s performance, and what it protects. It also disputes the auditor’s count of people and properties at risk because it “misses critical context on other flood infrastructure in the region and that location’s hydrology,” Ince said.

“Maintenance contributes to performance,” the department said in its letter, “but it is not the only or always the most effective action for reducing risk.”

Engler, whose districts include some on the list, had mixed reactions to the audit, which he said he was still reviewing.

“It has some things that I would definitely agree with, and it has a lot of things that I just go, ‘Who did they talk to about that? That’s totally off base,’” he said.

He echoed state water managers that most threatening issues for levees aren’t maintenance deficiencies, but long-term structural problems dating back to their construction generations ago.

He also said some of the agencies on the “unacceptable” list shouldn’t be there. Many, the audit reported, were listed because of chronic problems with burrowing rodents and overgrown vegetation — which can obscure serious issues, or cause dangerous erosion when trees fall in storms.

But some, he said, were named simply because of timing: the livestock the local agencies enlist to graze down plants and brush hadn’t finished before the inspection, and the levee managers didn’t update the state after they were done.

“We know our levees are in good shape. We know the maintenance has been done,” he said. “Our rating never goes from unacceptable back to acceptable, just because we forget to report.”

Maintaining levees built generations ago — clawed at by ground squirrels and buffeted by water — is pricey.

State water managers said that they have provided $400 million to local agencies for levee maintenance over the last 10 years. But they told the auditor it would take at least $165 million more per year than they or local agencies currently spend to fully address levee maintenance in Central Valley areas over the coming decades.

Maintenance matters, the auditor said, “because it reduces the likelihood that levees will fail and cause flooding that would damage property and endanger lives.”

Instead of rising, the audit reports, state funding is dwindling .

Gov. Gavin Newsom earlier this fall vetoed a bill to create an annual repair fund for 1,100 miles of aging levees in the Delta, about a third of which fall under the State Plan of Flood Control, according to the Legislative Analyst. The rest are privately or locally owned.

In his veto message, Newsom said that funding in this year’s budget made the measure redundant. But the money comes nowhere close to the audit’s recommendations.

The state’s program to help local agencies pay for levee repairs isn’t keeping up either.

The audit reported that since 2012, state water managers have “been unable to complete repair projects as of August 2026 for 14 of the 48 critical sites,” meaning these issues could reasonably cause a levee to fail during a flood or high-water event. Most of those sites had been on the repair list since 2023, the audit said.

The program’s money is running out, and the department “does not have additional funding available to repair projects for new critical sites that it will inevitably identify,” the audit said.

Lawmakers also in recent years failed to provide the funding needed to continue a state-run Flood Maintenance Assistance Program. Without it, Meegan Nagy, general manager of Knights Landing Ridge Drainage District said, local agencies “now lack funds to work on deferred maintenance and execute larger projects.”

Nagy said the district was counting on the Flood Maintenance Assistance Program to help repair erosion that the U.S. Army Corps of Engineers had identified over long stretches. Now, without that money, the district has only the funds to continue repairs through next year.

Failing to fix these issues puts federal disaster recovery funds at risk.

“Sites that we have been proactively repairing under this erosion program can quickly become critical during high water,” Nagy said. That, she added, “could quickly lead to potential levee failure during a flood event.”

Adam Borchard, executive director of the California Central Valley Flood Control Association, urged lawmakers to take the audit “seriously and earnestly invest in our critical flood control infrastructure in the Central Valley.”

Engler said the fault of inadequate funding lies squarely with the California Legislature.

“Nobody cares about flood control because it’s not that big, hot, sexy topic,” Engler said.

That could change this winter. “Hopefully, it doesn’t pan out like it could,” he said. “But we’ll see.”

This story was originally published by CalMatters and distributed through a partnership with The Associated Press.