The reflecting pool is about to be drained, again. Here's what to know

By — Maria Ramirez Uribe Maria Ramirez Uribe Leave your feedback Share Copy URL https://www.pbs.org/newshour/politics/the-reflecting-pool-is-about-to-be-drained-again-heres-what-to-know Email Facebook Twitter LinkedIn Pinterest Tumblr Share on Facebook Share on Twitter The reflecting pool is about to be drained, again. Here's what to know Politics Jun 23, 2026 5:58 PM EDT Green water, floating liner chunks, and workers dumping jugs of hydrogen peroxide. These are the images that have characterized the Lincoln Memorial Reflecting Pool in the weeks since its reopening following President Donald Trump's ordered renovations. Pool and environmental science experts told PBS News the algae bloom is a common and natural occurrence. Trump says otherwise. Without evidence he has blamed people of vandalizing the Reflecting Pool by using a "box cutter or a knife" to make a 300-foot slit on the bottom of the pool and dumping "fertilizer in the water" to produce algae. WATCH: Plagued by algae and peeling paint, Reflecting Pool set to undergo more repairs Six people have been arrested for vandalism, Trump said in a social media post Tuesday. Among the arrested is former U.S. Olympic canoeist David Hearn who said he was detained after touching part of the loose coating that was still attached to the bottom of the pool. Educate your inbox Subscribe to Here’s the Deal, our politics newsletter for analysis you won’t find anywhere else. Trump announced his plans in April to refurbish the Reflecting Pool, which he described as a "dirty disgusting place," in preparation for the country's 250th anniversary. At the time he said the pool's renovation, which included painting the bottom "American flag blue," would take around two weeks, cost up to $2 million and last "30, 40, 50 years." Two months later, the project has cost $14 million so far and is expected to require additional repairs, including emptying the pool again. Here's what we know. Why is there algae in the reflecting pool? Algae is a naturally occurring, microscopic organism that feeds off nutrients such as nitrogen and phosphorus. It's likely the water used to refill the Reflecting Pool had enough of those nutrients for the algae to grow, experts told PBS News. And the warm weather, sunlight and stagnant water gave the algae the perfect conditions to thrive. Steve Goodale, a swimming pool expert , refers to this phenomenon as "new pond syndrome." As a new pool starts filling up, there's the opportunity for algae to form because there isn't enough beneficial bacteria yet present to counteract the plant-like organisms. Algae blooms in the Reflecting Pool are neither new nor unique, especially in the hot summer months. A combination of pictures show the renovations of the Reflecting Pool taken June 12, June 16 and June 18, 2026, which was painted blue at the directive of President Donald Trump, ahead of the 250th anniversary of U.S. Independence, in Washington, D.C. Photos by Eric Lee, Evan Vucci and Annabelle