Sletten Lake is a small, 24-acre lake with a maximum depth of 46 feet. It has very soft (unmineralized) water. The lake bottom along the shoreline is boulder, ledgerock, and muck. Aquatic plants are sparse and grow to a depth of 9 ft; waterlilies and burreed are the most common. There are no inlets. The outlet to Tee Lake has a beaver dam which limits fish movement.
Sletten Lake's littoral zone (that portion of the lake that is less than 15 feet in depth, where the majority of the aquatic plants are found, is a primary area used by young fish, and provides the essential spawning habitat for most warmwater fishes) is 16 acres. The lake's fish species include green sunfish, hybrid sunfish, largemouth bass and Green Sunfish.