WASHINGTON — The Reflecting Pool at the Lincoln Memorial turned green with algae less than two weeks after the completion of a $14.2 million renovation project aimed at addressing longstanding issues of leaks and algal growth. The refurbishment, carried out by the Trump administration ahead of the nation's 250th birthday celebrations, involved coating the pool’s concrete floor with a dark blue waterproofing material and installing an advanced water-treatment system.

Despite initial gleaming conditions after the reopening, persistent hot and humid weather contributed to the rapid reappearance of algae, discoloring sections of the pool’s surface by Sunday and Monday. In response, National Park Service personnel and contractors waded into the pool to remove algae blooms. They were supported by workers from Pearl Purity Water Solutions, a Maryland-based firm that has held a treatment contract for the pool since 2021.

The Interior Department, responsible for managing the site, confirmed the installation of a water-purification system featuring nanobubbler technology, which is designed to eliminate algal growth. “Due to deploying the advanced nanobubbler technology, the algae is dead and being vacuumed up as we speak," said Interior spokeswoman Katie Martin. She also expressed gratitude to President Trump for the refurbishment efforts, noting the project’s goal of permanently resolving the pool’s issues.

Prior to the renovation, President Trump criticized the pool’s condition as “filthy” and “dirty,” emphasizing that the upgrades would make the landmark “beautiful.” The waterproofing applied to the pool floor was described by the administration as “American flag blue.”

The project included two no-bid contracts awarded without competitive bidding, citing urgency due to the upcoming 250th-anniversary events. Atlantic Industrial Coatings, a Virginia-based company, was tasked with sealing joints and applying the waterproof coating, completing its work by June 4. Ohio-based Greenwater Services installed the upgraded water-treatment system. Neither company responded to requests for comment.

Public reaction to the algae varied among visitors. Bonnie Garvin, a teacher from Monticello, Georgia, expressed little concern, noting that since people do not swim in the pool, the algae posed no real problem. In contrast, Jessica Lea, a therapist from Portland, Oregon, described the pool as “pretty swampy,” expressing disappointment in the appearance of the century-old landmark and lamenting the absence of its usual reflective qualities.

The Park Service continues efforts to clear the algae as officials monitor the effectiveness of the new systems in maintaining the pool’s condition going forward.