5 Colo. Code Regs. § 1003-5-3.4
All skimmers, when provided, shall comply in all respects with the NSF standards. At least one skimmer shall be provided for each 400 square feet of water surface or fraction thereof, with a minimum of two skimmers on opposite sides and at opposite ends. The skimmers shall be capable of continuously removing 100 percent of the designed turnover rate. The skimmers shall be built into the pool wall. The skimmers shall be adjustable and shall operate freely with continuous action to variations in water level over a range of at least four (4) inches.
All parts of the skimmer must be in place and in good operating condition. An easily removable and cleanable, properly fitting basket or screen shall be provided, through which all overflow water must pass to trap trash and debris with deck top access to facilitate cleaning. Each skimmer shall be provided with an equalizer line and skimmer equalizer line check valves. The equalizer pipe shall provide an adequate amount of water for pump suction should the water of the pool drop below the weir level. Weirs and float valves must be in place and in proper working condition. If any other device, surge tank or arrangement is used, a sufficient amount of water for pump suction shall be assured.
5 CCR 1003-5-3.4