(CNN) – CNN has learned millions of Americans are drinking water from systems violating lead rules, and it’s no secret to the government.

More than 18 million Americans are getting their drinking water from systems that have violated federal lead rules. Not only does the Environmental Protection Agency (EPA) know about it, the agency has done almost nothing to enforce its own regulations, according to multiple industry experts

“I think that the public needs to be told the truth about contamination in their water supply,” said Erik Olson, of the Natural Resources Defense Council.

More than 5,000 water systems are in violation, including failure to properly test water, failure to report contamination, and failure to treat water properly, according to a new analysis by the Natural Resources Defense Council (NRDC).

In 9 out of 10 cases, the EPA took no enforcement action when water systems violated the “lead and copper rule” – the federal regulation meant to keep America’s tap water safe from lead.

“Imagine a cop sitting, watching people run stop signs, and speed at 90 miles per hour in small communities and still doing absolutely nothing about it. That’s unfortunately what we have now,” Olson said.

Olson is among the experts saying water utilities are routinely “gaming the system,” using incorrect testing methods to “avoid detecting high levels of lead.” What that means is there are more water systems with lead issues, that aren’t officially in violation.

“They don’t care if they’re violating the law, they don’t feel like they’re going to face any penalties,” he said.

Philadelphia is one city accused of gaming the system. In 2014, city officials sent residents questionable instructions for testing – telling them to pre-flush their water and to remove aerators, which often trap particles of lead. Experts say both techniques would make lead levels appear lower than they actually are.

In fact, the EPA instructed as far back as 2007 that they “should not remove or clean aerators.”

“I wanted to test my water,” said Jonathan King, of the Philly Unleaded Project.

King’s 18-month-old daughter has been drinking Philadelphia’s water from the tap since she was born. He’s organizing a group of homeowners to get independent answers because he doesn’t trust the way the city conducted its testing.

“It concerns me that they’re not using the best practices available. It concerns me that they’re not following the latest EPA regulations,” he said.

So why doesn’t the EPA enforce its own rules? Multiple sources and industry experts told CNN that it comes down to two key reasons – water isn’t a main priority for the EPA because its resources are stretched thin, and the EPA has a cozy relationship with the water systems it’s supposed to regulate.

“They’re friends, they hangout with each other, they ask for each other’s advice, and you get close after awhile,” Olson said.

“Citizens should be very concerned,” said Alan Morrissey, who retired from the EPA’s Office of Civil Enforcement.

When Morrissey retired last year from his job as an EPA water department enforcement officer, he said he was frustrated because blatant violations would go without punishment. Morrissey says even EPA employees don’t trust what comes out of the tap.

“So most of my colleagues have all chosen to install a water filter underneath our kitchen sink,” he said.WEB LINKS:

What’s in Your Water? Flint and Beyond —> https://www.nrdc.org/resources/whats-your-water-flint-and-beyond