Frederick Hill III, the owner of Gotta Go Now portable toilets, loads porta-potties onto trucks with the help of Chris Lopez, left, in Upper Marlboro, Md. (Melina Mara/The Washington Post)

President Trump vowed on the campaign trail to boost economic growth and be the “greatest jobs producer that God ever created.”

His economic legacy is far from sealed, but it’s safe to say he has made at least one industry flush: the Washington region’s portable toilet industry.

The Trump presidency has brought an increased number of protests — and, yes, bladders and bowels — to the Mall. Protest organizers are renting record numbers of porta-potties in the Trump era for demonstrators to relieve themselves between chants and marches.

The National Park Service, which oversees the Mall, requires demonstration permit holders to provide one portable toilet for every 300 participants, 20 percent of which must be wheelchair-accessible, said Mike Litterst, a spokesman for the agency.

During January’s Women’s March on Washington, for instance, that meant nearly 600 privies — an entirely insufficient number that snarled throngs of antsy protesters in long bathroom lines.

Hill talks with other Gotta Go Now workers. (Melina Mara/The Washington Post)

Rob Weghorst, chief operating officer of Virginia-based portable toilet rental company Don’s Johns, said the increase in political advocacy — typically among protesters with left-leaning political affinities — has translated to boom times. His company, which recently acquired former competitor Gene’s Johns Toilets, provided toilets for the Women’s March, the Peoples Climate March and others on the Mall this year.

“All I’m going to say is that we love the activism. I’ll leave it at that,” Weghorst said. “It’s been good. It’s made for an interesting and lucrative spring.”

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The NPS said it has seen more than a 30 percent increase in permitted protests compared with this time last year, with some attracting tens of thousands of people. And however urgent the protesters’ causes, other urgent needs inevitably emerge during a long day on the Mall for the properly hydrated.

Frederick Hill III, owner of the District-based Gotta Go Now, says his porta-potty company has seen about a 40 percent increase in revenue each month of 2017 compared with a year earlier. So far in May, business is running 50 percent ahead of last year.

Both Weghorst and Hill said long-term rentals on construction sites still account for the bulk of their business. But Hill said protests are particularly fruitful since the events typically last only a day and the toilets — most often associated with foul smells and grimy conditions — sustain only minimal damage, but carry a pretty rental price tag.

Depending on the bulk of the order, Gotta Go Now charges between $85 and $125 per toilet, including delivery and pickup.

So far in May, Gotta Go Now’s business is running 50 percent ahead of this month last year. (Melina Mara/The Washington Post)

“It seems that there are protests every week that we are doing,” Hill said. “We’re quite active with them.”

For first-time protest organizers, the cost of portable toilets can be unexpected and staggering. Jordan Uhl, a District resident planning the March for Truth on June 3 near the White House, said portable toilets will be the biggest cost of the protest — an expense of nearly $5,000 he wasn’t expecting to incur.

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The March for Truth will call for a fair and transparent investigation into Trump’s presidential campaign’s alleged Russia ties, with the main demonstration occurring in Washington, along with dozens of smaller protests across the country.

In an era when many people casually RSVP to protests via Facebook, Uhl said, pinning down an accurate head count — and therefore, knowing how many porta-potties to rent — is difficult. Ordering more toilets than needed is a waste of money. Too few toilets brings its own set of unsavory challenges.

“I have a totally different perception now of how these things happen. It makes sense; it’s just difficult,” Uhl said. “I guess it’s just a compliment to Trump that he has been great for the local portable potty industry. That’s one good thing he’s doing.”

Uhl and other March for Truth organizers launched an online funding campaign to help pay for the protest’s expenses. While those contributing are ostensibly donating to a progressive cause, much of the donated money is going toward toilets.

Actress Alyssa Milano made her own $500 contribution to the March for Truth and is happy to help defray the toilet costs. She said she hopes to attend the march, writing in an email to The Post that Trump’s “war on truth may be the most important issue we face.”

“I’m fine with my money going wherever the organizers need it to go to make this a special moment in democracy,” Milano wrote.

For veteran D.C. organizers, the complicated and messy toilet logistics come as no surprise.

Janaye Ingram, a national organizer for the Women’s March who has planned numerous Washington protests, said getting toilets for the Women’s March the day after the inauguration was particularly tricky. Most of the region’s portable toilet reserves already were staged around the Mall for the inauguration, but each needed to be cleaned with toilet paper replenished in less than 24 hours.

In the end, organizers couldn’t secure enough toilets for the large crowd, even though lavatories still ended up being one of the march’s biggest costs.

“The toilets were a huge part of our budget, and they do cost more than what people anticipate them costing,” Ingram said. “Any time you are planning a march, you need to make sure that people can see, you need to make sure that people can hear, and you need to make sure that people can go to the restroom.”