California Democratic Rep. Maxine Waters continued her longstanding practice of funneling campaign cash to her daughter to run a lucrative operation during the 2022 election cycle, which netted the younger Waters another six figures in payments.

Karen Waters pocketed $192,300 from her mother's campaign to keep her "slate mailer" operation afloat between Jan. 2021 and Dec. 2022, a Fox News Digital review of Federal Election Commission filings shows. The setup involves outside campaigns paying Waters' campaign to appear on the slate mailers - or endorsement mailers - sent out to constituents in the Los Angeles area. 

The practice is highly unusual on the federal level, and Waters appears to be the only national politician using it to grab committee cash. Slate mailers, however, are commonplace in her home state of California, though critics say it involves deceptive practices over one campaign paying another for a politician's backing in an election.

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Maxine Waters

Rep. Maxine Waters appears to be the only federal politician running a slate mailer operation. (AP Photo/J. Scott Applewhite)

Waters received the green light to run the operation from the Federal Election Commission in the fall of 2004. Since then, Karen Waters has received more than $1.2 million in payments from her mother's campaign.

The practice has also proved profitable for Waters' campaign. While most of the cash it garners is from individuals running for local public offices in the Golden State, state-wide politicians have also paid large sums to appear in the Waters mailers, including Vice President Kamala Harris. 

Maxine Waters

Maxine Waters has funneled more than $1.2M to her daughter throughout the years to over see her slate mailer setup. (AP, File)

In 2010, when Harris sought the California attorney general spot, her campaign sent $33,000 to Waters' campaign for slate mailer placement. Later, in 2016, Harris paid $30,000 more to appear again while running for the U.S. Senate, filings show.

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Maxine Waters

Prominent California politicians such as Vice President Kamala Harris and Gov. Gavin Newsom have paid Waters' campaign to appear on the slate mailers. (Alejandro Alvarez/Twitter)

Additionally, Democratic Gov. Gavin Newsom paid Waters $45,000 for the service while running for lieutenant governor in 2010, and former Sen. Barbara Boxer spent a combined $33,000 in 2010 and 2018 on the mailers. 

More recently, controversial Los Angeles District Attorney George Gascón dished out $36,500 to Waters' committee for the slate mailers during his 2020 campaign. 

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Waters' campaign did not immediately return a Fox News Digital request for comment on the payments.