The reappearance came less than one week after contractors completed a sweeping renovation project intended to rid the century-old landmark of the persistent blooms once and for all.
The Interior Department said the algae is residual, the result of supply lines that sat dormant for eight weeks during construction. A department spokesperson described the current bloom as part of a normal startup process and indicated that the residue would dissipate as the new filtration system reaches full operation.
The renovation was a centerpiece of President Donald Trump’s broader plan to refresh the capital ahead of the nation’s 250th anniversary. Trump, who has called the reflecting pool “filthy” and “dirty,” claimed before the work began that the pool would look “far more beautiful, more beautiful than it did in 1922” upon completion. The project started in April and wrapped up last week.
Federal contracting records show that $1.7 million was awarded to Green Water Solutions for a new ozone nanobubbler filtration system, while $14.2 million went to Atlantic Industrial Coatings to line the pool in a shade called “American Flag Blue.” The total cost far exceeded the roughly $1.5 million price tag that Trump originally cited when he announced the work.
The Interior Department spokesperson defended the expense, stating that “President Donald J. Trump is an expert builder who has fixed the reflecting pool for good unlike the failed and extremely costly attempt by Obama and Biden.” The pool was last renovated in 2012 under President Barack Obama, a two-year, $34 million project that installed an ozone water filtration system for the first time. Two months after that renovation, the National Park Service drained the pool and doubled its ozone levels to combat large clumps of algae that had already formed.
Eddie Wood, owner of Atlantic Industrial Coatings, said his company did a great job on lining the pool this spring. The National Park Service has also assigned a dedicated maintenance crew to manage wildlife and grounds around the pool as part of the new upkeep plan.
The recurring algae problem underscores the difficulty of maintaining a shallow, exposed body of water on the National Mall. Ozone technology works by neutralizing the nutrients that algae need to grow, but both the 2012 and 2025 systems have faced challenges in keeping the pool clear immediately after installation.
