WASHINGTON — In the wake of the Flint water crisis, states are rushing to test for high levels of lead in drinking water. But many are failing to come to grips with a more insidious problem: lingering lead paint in homes and schools.

Paint, rather than drinking water, remains the main source of lead poisoning of young children in the U.S. But even though there are myriad federal and state laws designed to eradicate lead paint, enforcement is lackluster, hampered by a lack of money and the misperception that the problem has been solved. Many state laws don’t conform to federal recommendations, and federal funding for lead abatement has been slashed from $176 million in 2003 to $110 million in 2014.

Though the federal government banned lead-based paint in 1977, it persists in an estimated 38 million homes, lingering on old window frames and trim, and in dust. According to the U.S. Centers for Disease Control and Prevention, children in at least 4 million U.S. households are being exposed to “high levels” of lead, and an estimated 535,000 children between the ages of 1 and 5 have elevated lead levels in their blood. (The CDC does not consider any level of lead safe for children.)

Lead poisoning in children has been linked to lower IQs, hormonal issues and behavioral problems, costing U.S. taxpayers an estimated $55 billion annually. A 2009 study determined that every dollar spent on limiting lead exposure saved taxpayers between $17 and $221 by reducing spending on health care, special education and crime.

Under federal rules finalized in 2010 after many years of delay, workers and firms engaged in renovation, repair and painting must be certified and trained in the use of lead-safe work practices. But environmental health experts, such as Tom Neltner of the Environmental Defense Fund (EDF), say enforcement of the federal rules at the state and local level is inconsistent.

“We’ve known how to solve this problem for years,” said David Jacobs, chief scientist at the National Center for Healthy Housing. “What we lack is the political will and funding from both private and public sources. Rather than let this thing drag on for another several decades, we should do the smart thing and invest, so that kids don’t have reduced IQs and behavioral problems.”

Some states, such as California, Indiana, Maryland, Massachusetts, Minnesota, Michigan and Ohio, have rigorous lead abatement laws on the books, said Neltner, chemicals policy director of the EDF. But in others, laws are weak or inconsistently enforced.