Some of America's highest paying jobs — such as surgeons, lawyers and psychiatrists — require years of school and multiple degrees. But star of ABC's "Shark Tank" and business mogul Kevin O'Leary says that going to college isn't the only route to getting rich.

"I don't recommend college for everybody," O'Leary tells CNBC Make It. "The fact is, there's a lot of trade schools that would help you make a lot more money.

"Be a plumber, they get rich," he says. "Everybody has to have a plumber, even in a recession."

The best way to think about school is to figure how much debt you'll incur and how you plan to use your education to pay that off, O'Leary previously told CNBC Make It. "You have to think about education as an investment because it's going to cost you money and it's going to create debt for you in many cases."

To that point, trade schools are often less than four years and the cost tends to be less than a traditional university education, especially when compared to out of state or private colleges. With U.S. student loan debt setting a new record of $1.5 trillion owed in 2018, a new report from Merrill Lynch and Age Wave found that 36% of college graduates paying off student loans say that taking on that debt wasn't worth it. (Though there is research that shows increased educational attainment drives positive outcomes like longer life expectancy, higher earnings and lower unemployment.)

Meanwhile, CNBC Make It found seven occupations that pay more than $55,000 a year that are rapidly hiring workers and do not require a college degree. Those jobs include makeup artists, construction and building inspectors and electrical power-line installers and repairers.

O'Leary says such "pragmatic careers" are a good option.

"Think about all the trades — roofers, construction, home building," O'Leary says. "There's so much demand for this that people often overlook them saying 'I'm going to poo poo that career.' Why? You can get rich there a lot faster than getting a history major."

In particular, O'Leary advises if you're looking at trade schools, consider studying to be an electrician or a plumber.

"Every single building on earth wants to have electricity and plumbing working," he says. "Think about it that way. I don't care where you are, people are going to want your services."

Indeed, plumbers were ranked 59 on U.S. News & World Report's 100 Best Jobs for 2019, ahead of occupations like market research analyst, veterinarian and sales manager. Plumbers made a median salary of $52,590 in 2017, according to the ranking, although the best-paid 25% made $69,710, while the lowest-paid 25% made $39,470.

The occupation has an unemployment rate of 4.7%, and the Bureau of Labor Statistics projected a 15.6% employment growth for plumbers between 2016 and 2026. As the U.S. News & World Report ranking notes, the most common way to become a plumber is through an apprenticeship.

"Find something where people spend on it every single day…" O'Leary adds. "These are careers that actually can help you provide for your family forever."

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Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."