This webpage is updated monthly with information provided by Zion National Park. The Utah Division of Water Quality does not routinely conduct HAB sampling within the Virgin River Watershed. If you have additional questions, please contact Zion National Park by calling (435) 772-3256.
This webpage is updated with information provided by Zion National Park.
Updates
La Verkin Creek:
Check for mats
Monitoring for harmful algae on July 8, 2025
Harmful algae mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
Lower Virgin River:
Check for mats
Monitoring for harmful algae on July 8, 2025
Harmful algae mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
Lower Virgin River:
Looks Good
Monitoring for harmful algae on June 23, 2025
GOOD NEWS: Our monitoring team did not see any visible signs of harmful algae mats (benthic cyanobacteria) at the recreational sites they visited. However, mats may be present at other sites or regrow before our next visit. Know what to look for and check before letting children or pets in the water.
North Creek (including “The Subway”):
Warning Advisory
Recent monitoring on June 17, 2025
Harmful algae mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Warning Advisory
Recent Monitoring on June 16, 2025
Harmful algae mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
La Verkin Creek:
Health Watch
Recent Monitoring on June 16, 2025
Harmful algae mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source
Lower Virgin River:
Looks Good
Monitoring for harmful algae on June 6, 2025
GOOD NEWS: Our monitoring team did not see any visible signs of harmful algae mats (benthic cyanobacteria) at the recreational sites they visited. However, mats may be present at other sites or regrow before our next visit. Know what to look for and check before letting children or pets in the water.
North Creek (including “The Subway”):
Warning Advisory
Monitoring for harmful algae on October 1, 2024
Harmful algae mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Warning Advisory
Monitoring for harmful algae on October 1, 2024
Harmful algae mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
La Verkin Creek:
Health Watch
Monitoring for harmful algae on October 2, 2024
Harmful algae mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algae mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
