Minn. R. 4717.1050
NO LIFEGUARD WARNING SIGN
When a lifeguard is not on duty at a public pool open to use, a warning sign must be placed in plain view. A. The sign must state in clear, legible letters at least four inches high: "Warning - No lifeguard on duty." B. The sign must state in clear, legible letters at least one inch high: "Children must not use the pool without an adult in attendance."