Could Flint’s drinking-water crisis be just the tip of the iceberg? A new analysis by the Natural Resources Defense Council found that, last year, more than 5,000 drinking-water systems serving some 18 million people violated the federal law for testing lead levels in their supplies.

Moreover, the problem may be even more pervasive because many more water networks known to have such violations—including Flint’s system—do not even show up as having lead violations in the government database designed to track such water quality problems, according to the analysis by NRDC scientists and health specialists in the June 28 study.

Not all the systems identified in the report had elevated levels of lead.

Violations included failure to test water properly for lead and for conditions that could cause lead contamination; failure to report contamination to state officials and the public; and failure to treat the water appropriately to reduce corrosion.

But in 2015, 1,110 community water systems serving some 3.9 million people showed lead levels in excess of 15 parts per billion (ppb) in at least 10% of the homes tested—the action level established for lead under the rule.

The findings seem to substantiate claims made by critics such as Marc Edwards, the Virginia Tech engineering professor who helped to bring to light many of the problems in Flint. For years, he has maintained that the U.S. Environmental Protection Agency is derelict in its enforcement of the so-called lead-and-copper rule. The agency enacted the regulation in 1991 to ensure that lead does not leach into public water supplies.

NRDC and others say an overhaul of the rule is long overdue. The rule was last revised in 2007, and the next proposed update won’t be released before next year. Edwards says he would be happy to see the EPA properly enforce the current law.

NRDC based its conclusions on an analysis of EPA violation and enforcement records as well as geographic-information-system mapping software, to highlight and map the scope of lead-related issues in drinking-water systems across the U.S.

Additionally, the advocacy group says it has documented underreporting of problems in EPA’s drinking-water database for 25 years.

“Shoddy data collection, lax enforcement of the law and cities gaming the system have created a potent brew of lead violations and unsafe drinking water from the water supplies used by millions of people across the nation,” says Erik Olson, NRDC health program director and a report author.

Olson says that, in 2015, nine out of 10 rule-breakers faced no enforcement action. State agencies and the EPA sought penalties against only 3% of the systems that violated the rule. “The message sent to water suppliers that knowingly violate the law is clear: There is no cop on the beat,” Olson says.

Cynthia Giles, EPA’s chief enforcement officer, disputed some of NRDC’s statistics at a June 29 Senate Environment and Public Works subcommittee hearing. “I’m not really sure where NRDC got its numbers,” she said.

Giles said that, in 2015, state agencies issued approximately 6,000 enforcement actions for drinking-water violations of the Safe Drinking Water Act and the lead-and-copper rule. The number of federal EPA enforcement actions—about 100—was lower because the federal agency is focused primarily on oversight, leaving much day-to-day enforcement to state agencies, she said.

Still, Giles said she agreed that “drinking-water compliance and enforcement is at the top of the list of priorities for EPA, and I know state agencies feel the same way … and we appreciate efforts by NRDC and others to draw more attention” to the issue.

The NRDC report casts some blame on Congress, which has “decimated” the EPA’s budgets over the past six years. At the hearing, Sen. Ed Markey (D-Mass.) noted that, between 2010 and 2016, the agency’s compliance-and-enforcement budget has been cut by 9% and its workforce slashed by 17%.

“We have, along with the rest of the agency, struggled with declining budgets,” said Giles. “We direct our enforcement attention to the most serious situations.”

EPA issued an enforcement order for Flint in January, and the problems there remain a top agency priority, she said. “We are working closely weekly [and] daily with the city of Flint and the state of Michigan” to ensure that the drinking water is safe, Giles emphasized.

Officials from engineering firms that work in the water sector say the vast majority of water utilities are vigilant about water quality, preventing contamination problems and addressing them quickly when they occur.

Doug Owen, executive vice president of Arcadis North America, says the vast majority of the 155,000 public water systems across the U.S. are “large public systems” that serve 94% of the total drinking-water supply and “have capability and capacity” to ensure that water is safe.

The problems that do arise tend to happen when a switch is made, either in water supply, disinfectant or another element of the treatment process, he says.

“Pipes get used to the kind of water that is used. They [develop] a natural equilibrium,” Owen says. But when the source changes, “you have a different water quality that can upset that equilibrium, which is why you have to be very careful when you make these changes,” he adds.

Cindy Wallis-Lage, president of Black & Veatch’s global water division, concurs. As demand increases over the next years, utilities will look more and more to using multiple sources of supply, from ground­water to water that has been recycled or desalinated, she says. Utilities, operators and the engineers that assist them “need to make sure we understand that when we have a blended source. How do we manage all those elements to allow us to make sure we have that security in the water supply all the way to the last tap?” she asks.

Some utilities have responded quickly and appropriately to the discovery of elevated lead in drinking water, Owen says. During the 1990s, when Tucson, Ariz., switched to surface water from groundwater, pipe corrosion problems quickly occurred, but the city “rallied, got themselves around it and solved that problem,” he notes. Similarly, utility DC Water in Washington, D.C., was quick to address elevated lead levels discovered in the early 2000s because of a change in disinfectant, Owen adds.

He says it is sometimes the smaller systems and even mid-size systems like Flint that may not have the resources, funds or capacity to make the right decisions when confronted with water-quality issues. 

Bob Hulsey, Black & Veatch’s director of treatment technology, says the Flint debacle has forced utilities to take a “laser-like” focus on their compliance with the lead-and-copper rule and water-quality issues in general.

“If they weren’t before, they are now,” Hulsey says, adding that he expects many more utilities to consider complete or partial lead-line removal in the next few years.