Austin’s watershed protection department has observed mats of blue-green algae, which may be toxic, on Lady Bird Lake and Lake Austin. The department notes that the algae may be present throughout both lakes and in other Austin waterways, and hotter weather this summer could lead to further spread.

Staying Safe

Residents and their pets should avoid any contact with algae mats. The city advises avoiding entry into any waterway with algae along the shoreline, stagnant or murky water, or scum or surface film. After swimming, residents should thoroughly wash their bodies and hair, and pets should also be rinsed.

In case of illness after swimming, residents should immediately contact their doctor or veterinarian. Austin is also encouraging both human and animal algae-related illnesses to be reported directly to the city online.

Prevention Efforts

Austin Watershed Protection previously initiated a five-year, $1.5 million pilot program to reduce algae growth, which involved applying lanthanum-modified clay to manage phosphorus in waterways’ sediment. No treatments were applied this spring, as 2026 is a control year to evaluate the pilot’s effectiveness and cost benefits.

Original reporting: Community Impact — Austin — read the source article.