Division of Water Quality
Matt Warner Reservoir Recreational Monitoring
Matt Warner Reservoir is located on Diamond Mountain, north of Vernal in Uintah County. DEQ’s recreational water quality monitoring checks for two health concerns: Harmful Algal Blooms (HABs) and Waterborne Pathogens (E. coli). Find the most recent monitoring information below.Warning AdvisoryHarmful Algae Present
Do not swim or water ski
Avoid areas of algae when boating
Keep animals away
Do not drink the water
Clean fish well and discard guts
Learn More About Harmful Algal BloomsReport a Bloom • (801) 536-4123
Utah Poison Control • (800) 222-1222UpdatesAugust 19, 2026: Harmful algal bloom (HAB) monitoring update
BE CAREFUL: A harmful algal bloom is present at Matt Warner Reservoir. Algae in the water may be producing dangerous toxins that can make humans and animals sick.
If you visit the area:
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
Fishing HABs Photo ExamplesRecreational Water Quality Home
