Harmful algal bloom advisory issued at Deer Creek Reservoir’s East Wallsburg Bay

A harmful algal bloom advisory is in effect at East Wallsburg Bay in Deer Creek Reservoir, putting a key Wasatch Back recreation spot under a public-health warning. For Summit County families, boaters and weekend visitors, the immediate message is to stay out of the posted water and keep pets away from anything that looks green, scummy or discolored.

Swimming or wading in the affected area is unsafe, along with swallowing the water or letting dogs drink from it. Utah recreation guidance also warns against using suspect water for drinking or cooking without proper treatment. In a Deer Creek warning issued in 2020, symptoms after exposure included vomiting, staggering, weakness, convulsions and difficulty breathing, and state algae guidance says blooms can harm pets and wildlife as well as people.

The warning is also a reminder that one clear shoreline does not mean the whole reservoir is clear. Utah Department of Environmental Quality’s general Deer Creek recreational monitoring page showed no current advisories in the snapshot returned with this notice, with swimming, boating and eating fish marked OK at the broader reservoir level. Utah’s recreational-water program watches for two problems in lakes, reservoirs and rivers, harmful algal blooms and E. coli, and the state says HAB season runs from May through October, the stretch when these warnings tend to surface and shift quickly from one bay to the next.

A 2026 Integrated Report excerpt also listed Deer Creek Reservoir as Not Supporting for some parameters, with harmful algal blooms among the issues that failed criteria. That history matters at a reservoir that draws Summit County residents, Park City visitors and other Wasatch Back travelers looking for a summer day on the water. If East Wallsburg Bay is posted, some visitors will simply move to another shoreline or another lake, but nearby options such as Echo Reservoir and Utah Lake are monitored too, so plans still depend on checking current conditions before driving out.

Utah State Parks tells visitors to check algae conditions before recreating, using the reminder “Take Time Before Playtime.” For boaters, swimmers and businesses around Deer Creek, the practical job now is simple: watch the posted notices, keep people and pets out of the bloom, and treat the reservoir as changeable until the water clears.