A swimming pool assembly, including a pool body defining a top edge and an bottom connected by a wall, an access port positioned through the bottom, a first conduit connected to the access port and extending away from the body, a valve connected with the first conduit, a second conduit connected with the first conduit and extending toward the top edge, wherein the second conduit is water permeable. An actuator is positioned in the second conduit and connected to the valve. First and second water level sensors are positioned to measure ground water level and pool water level. A microprocessor is operationally connected to the water level sensors and to the actuator, wherein when the ground water level exceeds the pool water level by a predetermined amount, the microprocessor sends a signal to the actuator to open the valve.