How are splash pad lines protected from freezing?

Freeze protection is the dominant engineering concern for splash pads in cold climates. Strategies layer together: bury all supply and drain lines below the local frost depth (36 inches in the Mid-Atlantic, 48 inches in the upper Midwest, 60+ inches in northern Minnesota and Maine). Slope all horizontal runs at 1/8 inch per foot toward a low-point drain valve. Install drain valves at every low point so winterization can blow each section dry. Use heat tape with thermostat control on any exposed above-grade sections (rare but sometimes necessary at fill or discharge points). Pump houses are insulated and may have low-wattage heaters during winter for residual humidity control. Even with all protections, full compressed-air winterization is required every fall — passive freeze protection alone fails when an early hard freeze hits before drain-down.