Reflecting Pool

In 1920, as the Lincoln Memorial was being built, Popular Mechanics magazine gushed about a stunning feature of the monument to the 16th president, writing, in part:

One of the most important and beautiful features of the Lincoln Memorial, now approaching completion in Washington…is a huge “water mirror,” or pool, which will reflect the colossal statue of the emancipator.

The “water mirror” would, of course, become the Reflecting Pool, which was the work of Lincoln Memorial architect Henry Bacon. Stretching some 2,000 feet (610 meters) from the steps of the memorial toward the Washington Monument at the center of the National Mall, the pool perfectly frames Lincoln’s view of the memorial to his predecessor and reflects the obelisk in its shallow waters.

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At least that’s what Bacon envisioned.

A troubled history

The Lincoln Memorial stands adjacent to both the Potomac River and the Tidal Basin, so when the time came to create the Reflecting Pool it was built on an area that was basically marshland that had to be dredged. (The Lincoln Memorial was built on similarly marshy soil, but more than 100 concrete pillars were driven deep into the earth to reach bedrock and secure the foundation; no such lengths were gone to for the Reflecting Pool.)

By the time the Reflecting Pool made its debut in 1923, it was a shallow surface coated with asphalt and tile constructed to hold millions of gallons of water. What happened over the ensuing decades now seems inevitable. By the 1980s the pool had sunk about a foot, and the solution was to pour a new concrete slab on top of the old one. The added weight only created more problems, and the cost of fixing them seemed too enormous to undertake.

The 2010–12 reconstruction

Then in 2010, with some $34 million from the American Recovery and Reinvestment Act, it seemed as if the Reflecting Pool’s problems could be fixed once and for all—and completed in time for the 50th anniversary of Martin Luther King, Jr.’s historic “I Have a Dream” speech in August 2013.

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The National Park Service (NPS) drained the pool, removing waterfowl feces and installing an elaborate pumping system that would bring water in from the Tidal Basin, circulate it through sand to keep it clean, and restore the pool to Bacon’s vision. The idea was that the pool’s water would be recirculated every few days. The project also tried to address the underpinning issues by driving more than 2,000 40-foot- (12-meter-) long wooden pilings into the marshy soil beneath the pool to bolster the foundation.

But almost as soon as the 2010–12 project was completed, the problems returned. The plastic pipes meant to carry the water from a new treatment plant to the pool cracked under the pressure from the surrounding soil. The new treatment plant proved inadequate to filter and clean the water. The pool’s concrete slabs expanded and contracted, creating leaks. The leaks make it nearly impossible to maintain water levels to allow the pool to actually reflect anything. Kym Hall, a former NPS official, said that “it’s like pouring water into a colander.” Some 16 million gallons (61 million liters) leak out of the Reflecting Pool each year, according to the Interior Department.

To make matters worse, when a pipe breaks the entire water filtration system needs to be shut down for repairs, sometimes for weeks. That allows enormous algae blooms to form on the surface of the water.

What causes the algae bloom?

The problem with algae growth isn’t unique to the Reflecting Pool. All bodies of stagnant water are particularly vulnerable to a process known as eutrophication (the gradual increase in the concentration of plant nutrients such as phosphorus and nitrogen), and the Reflecting Pool is no exception.

Nutrient inputs include decaying leaf litter and bird excrement that are deposited in the pool directly, along with fertilizer runoff and sewage, which enters the Potomac River and the Tidal Basin. Even though aeration units have been installed to add ozone to the water and slow the growth of algae, the pool’s water must still be cycled, which is where the problem of broken pipes again rears its ugly head. A new, more effective ozone unit is set to be installed in 2026.

The 2026 construction

The Reflecting Pool has drawn the attention of U.S. Pres. Donald Trump during both his presidential administrations, but in April 2026 he announced a plan to reseal the pool and paint it “American flag blue.” During his first administration, the NPS had said that the only solution to the problem was to replace thousands of feet of pipes, which was not done.

Within days of the 2026 renovation being completed, the algae was back. In response, the NPS added thousands of gallons of 12 percent hydrogen peroxide (H₂O₂)—a common pool-cleaning agent and an active ingredient in paint strippers in higher concentration—into the Reflecting Pool. However, just days after the chemical treatment was applied, the bottom coating of blue paint began to visibly crack and peel, raising questions about whether the added chemicals, combined with flaws in the repair work, contributed to the coating’s failure.

Trump initially indicated that the algae had been killed and would soon dissipate. Without citing evidence, except to say that it would come out in court, he also blamed the peeling paint on vandals, adding that in all likelihood the pool would need to be drained again for further repairs. On July 13, the pool was again drained with the president saying it would be “put back into service soon.” In August felony charges were dropped against one of the alleged vandals after prosecutors admitted in court documents that the damage was caused by “botched” work during the renovation.

The coverage of the latest chapter in the Reflecting Pool’s story has attracted news reporters and sightseers putting their hands in the murky waters. What is clear is that the 2026 incarnation is a far cry from the “water mirror” dreamed of a century earlier.