Blackridge Reservoir is located at 15000 South Ashland Ridge Drive (5390 West) in Herriman. DEQ’s recreational water quality monitoring checks for two health concerns: Harmful Algal Blooms (HABs) and Waterborne Pathogens (E. coli). Find the most recent Blackridge Reservoir monitoring information below.
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Updates
November 1, 2025: Recreational water quality monitoring update
Recreational water quality monitoring has ended for the season. Monitoring will resume in June or July 2026. Harmful algal blooms can occur year-round, so know what to look for and always check before recreating.
October 17, 2025: Harmful algal bloom (HAB) monitoring update
GOOD NEWS: Our monitoring team did not see any visible signs of a harmful algal bloom. Learn more about harmful algal blooms.
Site visited: Beach area
October 7, 2025: Harmful algal bloom (HAB) monitoring update
OK, but BE CAREFUL: Conditions have improved at Blackridge Reservoir the past two weeks. Only low levels of harmful algae were present. Avoid any visible algae when recreating.
If you visit Blackridge Reservoir, we recommend:
- Do not swim or water ski in areas of algae
- Avoid areas of algae when boating
- Clean fish well and discard skin and guts
- Keep animals away
- Don’t drink the water
- Know how to recognize a harmful algal bloom
September 16, 2025: Harmful algal bloom (HAB) monitoring update
BE CAREFUL: A harmful algal bloom is present at Blackridge Reservoir. Algae in the water may be producing dangerous toxins that can make humans and animals sick.
Herriman City has issued a WARNING ADVISORY and closed the reservoir.
If you visit Blackridge Reservoir:
- Do not swim or water ski
- Avoid areas of algae when boating
- Clean fish well and discard skin and guts
- Keep animals away
- Don’t drink the water
- Know how to recognize a harmful algal bloom
September 8, 2025: Harmful algal bloom (HAB) monitoring update
BE CAREFUL: A harmful algal bloom is present at Blackridge Reservoir. Algae in the water may be producing dangerous toxins that can make humans and animals sick.
Herriman City has issued a WARNING ADVISORY and closed the reservoir.
If you visit Blackridge Reservoir:
- Do not swim or water ski
- Avoid areas of algae when boating
- Clean fish well and discard skin and guts
- Keep animals away
- Don’t drink the water
- Know how to recognize a harmful algal bloom
August 7, 2025: Harmful algal bloom (HAB) monitoring update
BE CAREFUL: A harmful algal bloom is present at Blackridge Reservoir. Algae in the water may be producing dangerous toxins that can make humans and animals sick.
If you visit Blackridge Reservoir:
- Do not swim or water ski
- Avoid areas of algae when boating
- Clean fish well and discard skin and guts
- Keep animals away
- Don’t drink the water
- Know how to recognize a harmful algal bloom
August 4, 2025: Harmful algal bloom (HAB) monitoring update
BE CAREFUL: Our monitoring team saw visible signs of a harmful algal bloom at Blackridge Reservoir. There could be algae in the water producing dangerous toxins. We collected samples and results are pending. Check back here for updates.
In the meantime we recommend:
- Do not swim or water ski in areas of algae
- Avoid areas of algae when boating
- Clean fish well and discard guts
- Keep animals away
- Don’t drink the water
- Know how to recognize a harmful algal bloom
July 28, 2025: Waterborne pathogen (E. coli) and HAB monitoring update
GOOD NEWS: E. coli counts were measured below recreational thresholds and our monitoring team did not see any visible signs of a harmful algal bloom.
Site sampled: Beach area
July 17, 2025: Waterborne pathogen (E. coli) and HAB monitoring update
GOOD NEWS: E. coli counts were measured below recreational thresholds and our monitoring team did not see any visible signs of a harmful algal bloom.
Site sampled: Beach area
June 26, 2025: Waterborne pathogen (E. coli) monitoring update
GOOD NEWS: E. coli counts were measured below recreational thresholds. Sampling suggests that the water is safe from harmful bacteria and viruses.
Site sampled: Beach area
June 19, 2025: Waterborne pathogen (E. coli) and HAB monitoring update
GOOD NEWS: E. coli counts were measured below recreational thresholds and our monitoring team did not see any visible signs of a harmful algal bloom.
Site sampled: Beach area
May 19, 2025: Waterborne pathogen (E. coli) and HAB monitoring update
GOOD NEWS: E. coli counts were measured below recreational thresholds and our monitoring team did not see any visible signs of a harmful algal bloom.
Site sampled: Beach area
May 19, 2025: Harmful algal bloom (HAB) monitoring update
GOOD NEWS: Our monitoring team did not see any visible signs of a harmful algal bloom. Learn more about harmful algal blooms.
Site visited: Beach area