Colorado’s mountainous terrain is dotted with thousands of alpine lakes and reservoirs. While the state offers plentiful opportunities for boating and fishing, finding a body of water where swimming is permitted can be difficult. Many high-altitude lakes and reservoirs are subject to strict regulations limiting body-contact recreation. This article identifies specific, legally sanctioned locations where you can safely enjoy a refreshing swim.
Why Most Colorado Lakes Prohibit Swimming
The primary reason for widespread swimming restrictions relates to the role many of these bodies of water play in municipal water systems. A large portion of Colorado’s lakes, especially those along the populous Front Range, are reservoirs managed to supply drinking water to cities and towns. Direct bodily contact is often prohibited to mitigate the risk of contamination from human and animal waste, simplifying the purification process for municipal providers.
Safety concerns, particularly the risk of cold water immersion, constitute the second major factor. Even during the peak of summer, surface temperatures in deep mountain lakes rarely exceed 60 to 65 degrees Fahrenheit. Exposure to these temperatures can rapidly lead to cold water shock, causing an involuntary gasping reflex and immediate physical incapacitation. Furthermore, many high-altitude bodies of water lack necessary infrastructure, such as designated swim areas and lifeguards, making organized search and rescue efforts difficult.
The Best Lakes for Swimming
The most reliable places to find permitted swimming areas are within the well-managed boundaries of State Parks and National Recreation Areas, where designated swim beaches are monitored and maintained.
Chatfield State Park
Located southwest of Denver near Littleton, Chatfield State Park offers a large, sandy swim beach on its 1,423-acre reservoir. The swim beach area is roped off from the main body of the lake, which is heavily used for motorized boating. Access requires a daily State Park vehicle pass, which provides access to amenities like bathhouses, restrooms, and concession stands. The beach is open seasonally, generally from Memorial Day to Labor Day, but operates without lifeguards.
Cherry Creek State Park
Cherry Creek State Park, closer to the city of Aurora, features a designated swim beach on its 880-acre reservoir, providing a sandy shoreline easily accessible from the Denver metropolitan area. Similar to Chatfield, the park requires a daily vehicle pass for entry. This location includes a bathhouse with restrooms, though it is subject to temporary closures if routine testing reveals elevated E. coli bacteria levels.
Boyd Lake State Park
In Northern Colorado near Loveland, Boyd Lake State Park is a popular water sports destination with a designated swim beach on its nearly 1,700 surface acres of water. The swim beach area is strictly buoyed off from the main lake, prohibiting boats and pets to ensure swimmer safety. Amenities include rinsing showers, picnic tables, a playground, and a snack bar. Swimming is also permitted from boats in three designated no-wake areas on the lake.
Grand Lake
As Colorado’s largest natural lake, Grand Lake offers a public beach near the town center, providing a rare high-altitude swimming opportunity. While the water remains relatively chilly due to its high elevation, a designated swimming area allows for safe entry. The lake is generally free to access, although it is located near the entrance to Rocky Mountain National Park, which requires a separate entrance fee.
Blue Mesa Reservoir
Located in Curecanti National Recreation Area near Gunnison, Blue Mesa is Colorado’s largest body of water, offering a more rugged swimming experience. There are no officially designated swim beaches with facilities, but swimming is permitted along the shoreline, especially in areas with sandy banks like the Old Highway 50 beach or the Bay of Chickens. The surface temperature averages about 65 degrees Fahrenheit in the summer, and boat traffic is common outside of no-wake zones.
Essential Safety and Preparation
Even in designated areas, the water temperature poses a risk, and swimmers should enter the water slowly to minimize the physiological impact of cold water shock. This sudden immersion can trigger an uncontrollable gasping reflex and a rapid increase in heart rate.
Physical exertion in the thin air of a mountain environment requires modification to activity levels, especially for visitors arriving from sea level. Altitude sickness, which can begin around 7,500 to 8,000 feet, is exacerbated by the increased respiratory effort required for swimming and the dehydrating effect of the dry, high-altitude air. Symptoms often include headache, nausea, and fatigue; individuals should immediately cease strenuous activity and hydrate with water and electrolytes if they feel unwell.
Mountain weather can change dramatically and quickly. Rapidly developing afternoon thunderstorms can produce high winds, lightning, and large waves on the large surface area of reservoirs. Swimmers should exit the water immediately at the first sign of approaching storms. Always use designated swimming areas, remain within roped-off zones, and adhere to state park regulations.