08/10/2026
8/10/26 ATTENTION: An active algal bloom has been visually confirmed at Herrick Lake within Herrick Lake Forest Preserve.
Blooms are a common natural phenomenon, but have the potential to quickly turn harmful in warm weather and produce toxins which can make pets, children and people with weak immune systems sick if they ingest or inhale water that has algae present.
Harmful algal blooms can look like spilled blue, green, or brown paint on the surface of the water. Because it’s not possible to tell whether a bloom is producing toxins just by looking, we encourage the public to take the following precautions whenever a bloom is present:
• Avoid touching the water or algae.
• Keep pets away from the water.
• Wash skin or fur thoroughly if contact occurs.
Staff will continue to visually inspect water conditions and warning signs will remain on site while the bloom is occurring. Learn more about harmful algal blooms at the link below.
Learn about harmful algal blooms, including blue-green algae, in DuPage forest preserve lakes.