The BBC has contacted the contractor for comment.
Hearn’s lawyers said in a statement to BBC News, that the case “should have never been brought”.
“Its dismissal today does not erase the abuse of government power in arresting and charging a patriotic American who did nothing wrong. The government’s approach was ready, fire, aim.”
The Reflecting Pool underwent a multi-million dollar resealing and painting project this spring.
The monument had long been beset by structural failures and leaks, and Trump championed the project as part of his bid to beautify the capital city.
But, despite the makeover, which cost an estimated $16m (£12m), the pool had continued to be plagued by algae, and pieces of the blue sealant peeled off within days after its application.
The project, whose original budget was less than $2m, was awarded to a contractor chosen by Trump himself, CBS reported, and was not open to bidding from other companies as is typical for government work.
The admission on Friday represents a stunning about face by Trump and his administration.
