Algae appears in the Reflecting Pool after the completion of recent renovations at the direction of U.S. President Donald Trump to paint it blue, Washington, D.C., U.S., June 15, 2026. REUTERS/Jessica Koscielniak
It has been 14 years since the overhaul of the Washington D.C., reflecting pool was finished. It was the first time in 90 years that the reflecting pool was repaired, and a more cost-effective way to bring water into it was developed.
President Donald Trump this year spent millions to put a special coating on the pool he said would stop the algae.
In the past week, the algae returned.
On Tuesday morning, national park staff were videotaped pouring hydrogen peroxide into the pool. Mixing peroxide and chlorine into water can cause a chemical reaction that sanitizes the pool just like a swimming pool
CBS News reporter Bob Kovach filmed and posted on X.
A New York Times report from May walks through why this isn't going to work. First, Trump's renovation never addressed the pipes.
"Water is pumped from the Tidal Basin, an inlet of the Potomac River, to the treatment plant. There it is filtered and purified before being fed into the Reflecting Pool," the report says. "But when the water from the Tidal Basin is too murky or filled with algae — which is often — the pool is filled with city drinking water instead. This happens especially in the hot summer months, when algae blooms are prevalent."
The reality is that it doesn't matter where the water comes from, it won't stay clean for long. Wildlife waste, trash, people throwing in pennies to make a wish and dirt blowing in are all ways that the pool is being contaminated over time. When the weather is hot, algae forms because the shallow pool bakes in the sun.
"The treatment plant is supposed to combat this problem, using screens and sand to filter the water and a system that infuses the water with ozone gas, which kills algae and bacteria," the Times reported. "The first Trump administration had called for an upgraded ozone system to make the treatment more effective. This year, the Trump administration is spending $1.7 million to buy one."
The water is then cycled through the filters over and over to be reused. Every three or so days, the whole pool is filtered. The pipes keep leaking and breaking, however. The Park Service thinks this is due to the pressure of the surrounding soil.
“It’s almost impossible to maintain the water level that is required to make the pool reflective,” said Kym Hall, a former National Capital Area director for the National Park Service. “It’s like pouring water into a colander.”
This morning at the reflecting pool pic.twitter.com/uygkbcn7Mn
— bob kovach (@bkovoDC) June 16, 2026