Popular Dog-Destination Closed After Toxic Algae and 1,000 Dog Toys Found in Water

South Suburban Reservoir in Colorado Springs, Colorado used to be a super popular destination for families, especially those who wanted to let their dogs run loose and play in the water. While it wasn’t formally sanctioned, many pet parents would let their dogs swim off-leash in the reservoir during the summer, when the shoreline was open to the public. But after nearly 1,000 dog toys were found in the water, along with toxic algae and E. coli caused by human and pet activity, as of October 21, the reservoir has been closed.

The South Suburban Reservoir is one of two reservoirs in the 318-acre Stratton Open Space and was built in 1932. It stores raw, untreated drinking water — and served as a popular recreational space. Colorado Springs Utilities kicked off a maintenance project in April 2024, which involved draining the reservoir. It was during this drainage and maintenance that nearly 1,000 dog toys were found. 

Colorado Springs Utilities made the difficult, but necessary decision to close the reservoir for recreational access. It’s not just the dog toys that contributed to this decision, but the general health concerns that stem from dogs and humans alike swimming and wading in drinking water. 

“Splashing and swimming stir up sediment in the reservoir, increasing the amount of organic carbon and nutrients available to support the growth of algae, including toxic cyanobacteria (blue-green algae),” the official press release from Colorado Springs Utilities reads. “Additionally, pathogens such as E. coli are introduced when dogs swim in water. These situations not only create a dangerous environment for pets, but they have also required us to remove the reservoir from use in our system multiple times over the years. It does not hold enough water to effectively dilute these pollutants, making high-quality treatment more difficult.”

The South Suburban Reservoir was never formally approved for recreation by the Colorado Springs city council, and it lacks the space and resources to accommodate recreational activities. Years and years of this informal recreational use have taken a toll on water safety. After all, nearly 1,000 dog toys sitting in drinkable water for 20 years is bound to have some effects.

The utility management agency did emphasize to 9 News that while the dog toys did present issues especially when it comes to PFAS and microplastics in drinking water, it’s really a greater problem with the recreational use of water that the facility can’t handle. 

“The dog toys themselves can leach out plastics and other materials that contaminate the water," a CSU spokesperson said. "But the bigger issue really is the use of the water. We don't allow extended contact for humans or animals in any of our reservoirs throughout our raw water system.”

The reservoir is expected to be refilled in 2026. While the waters will be off-limits for swimming, wading, or dog activity, the hiking trails and other outdoor, not-in-the-water recreational facilities in the area will still be accessible.