Impeachment wasn't all that was on President Donald Trump's mind in the hours after the House voted to approve the charges against him.

He was also thinking about toilets.

Speaking at a campaign rally that night in Battle Creek, Michigan, Trump delivered a lengthy rant about a bevy of regulations governing bathroom and kitchen appliances.

"Sinks, right? Showers, and what goes with a sink and a shower?"

"Toilets!" the crowd chanted back.

"Ten times, right, 10 times," Trump continued, referring to the number of flushes he claimed were sometimes required because of water-saving federal regulations. "Not me, of course not me. But you," he added while pointing to a random audience member.

While Trump's remarks may seem a tad unusual, they echo a long-standing concern in some conservative circles.

For the better part of two decades, libertarian-minded conservatives have taken aim at the regulations and energy standards Trump now decries — and they're overjoyed to see him use the power of the presidency to shine a light into America's bathrooms and kitchens.

"I've never flushed a toilet 10 times," said Daniel Savickas, the regulatory policy director for the libertarian advocacy group FreedomWorks. "But I think what he's getting at is the heart of the issue. People do have to run their appliances multiple times because of water efficiency standards. I don't think people are flushing their toilets 10 times, but they're definitely reusing dishwashers, flushing multiple times, at least. And that has drawbacks across the economy."

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Leading environmentalists don't see it quite the same way. They point to the positive impact of the regulatory policy, primarily improved water conservation and lower bills for consumers. And the products are just as good as their less efficient predecessors, they said.

"I don't know what product they're using but I don't have to run it two or three times," former New Jersey Gov. Christine Todd Whitman, the Environmental Protection Agency administrator under President George W. Bush, told NBC News. "My dishwashers do just fine, thank you. I do it once. My dishes are clean and everybody's healthy. I don't know what they're talking about."

The more than 20-year battle Trump has given oxygen to centers on a series of regulations and energy standards starting with the 1992 Energy Policy Act signed by President George H.W. Bush. That law set new limits on how much water a toilet can utilize and, in 1994, kicked into effect a standard that said new toilets, showerheads and faucets had to have water-saving designs. Since then, the federal government has regulated water flow of faucets and showerheads.

Today's toilets can use as little as 1/5th the water as earlier models, which the EPA's website says "happen to be a major source of wasted water in many homes." Recent advancements allow for toilets to use even less water than what is the current federal standard, according to the EPA, which also promotes the water-saving abilities of newer showerheads and faucets online.

Since the 1990s, when then-Rep. Joe Knollenberg, R-Mich. — backed by influential conservatives like then-Reps. John Boehner, R-Ohio, and Ron Paul, R-Texas — sought to repeal the restrictions, conservatives have taken aim at those standards.

"Frankly, the toilets don't work in my house," Sen. Rand Paul, R-Ky., told Kathleen Hogan, deputy assistant secretary for energy efficiency in the Obama administration, during a 2011 congressional hearing. "I blame you, and people like you who want to tell me what I can install in my house, what I can do."

Trump pushed that issue to the forefront when he told reporters in the White House last month that the EPA would be "looking very strongly at sinks and showers and other elements of bathrooms," insisting that "people are flushing toilets 10 times, 15 times as opposed to once" and that "they end up using more water."

Gina McCarthy, EPA administrator under President Barack Obama, said in an interview, "Pardon the pun. This administration is throwing regulations and really great innovative programs that the federal government has used to push innovation forward, down the toilet."

EPA spokesman Michael Abboud said the agency is working across other federal agencies to "ensure American consumers have more choice when purchasing water products."

It's not just bathrooms that have sparked the president's ire.

Conservative groups such as FreedomWorks, through its "Make Dishwashers Great Again" campaign, and the Competitive Enterprise Institute have been influential in getting the Department of Energy to consider creating a new class of dishwashers with shorter wash cycles to get around existing standards.

Sam Kazman, the general counsel at CEI, said Trump's "sentiment" is right on, even if some of his specific claims were "overblown." He pointed to more than 3,200 comments submitted to the Energy Department as part of the effort to create a new dishwasher class as evidence the standards are causing public anger.

"This is based in reality, and it's based in the problems that the real people are having, and the folks who think there is no problem or who actually maybe designed and advocate these regulations, probably eat out a lot," Kazman said. "I think, basically, if the efficiency regs are producing better devices, devices that do save money and operate just as well, you do not need laws that mandate them."

Current dishwasher standards require that standard-size products use no more than 5 gallons of water per cycle, according to the Appliance Standards Awareness Project. Consumer Reports found that modern dishwashers use about half of the water and energy as those made 20 years ago.

Meanwhile, the Trump administration has previously sought to eliminate funding for Energy Star, an EPA program allowing companies to put the program's label on appliances that meet energy efficiency standards. It's a label that many dishwasher manufacturers seek to obtain for their appliances. The Energy Star-labeled dishwashers save an average of more than 3,800 gallons of water over the appliance's lifetime, according to Energy Star.

"Why you would want to draw back on something like (Energy Star) is beyond me," Whitman said, adding the program "gives the consumers a choice to be part of an effort to reduce our use of water and energy. It gives them a way to save money on both energy and on water. It's a consumer choice option to help improve the environment."

Michael Brune, executive director of the Sierra Club, said killing the regulations governing household appliances will lead to more wasted water and energy, increased pollution and will reward companies that refuse to innovate.

"There are so many more important things that we should be talking about in our country, honestly," he said. "It's ridiculous that this is even a topic of debate."