First Flush In-Ground devices are essential if your property is located on a sloping allotment. The devices are designed to prevent bird droppings, mosquito eggs, debris, and other contaminants from getting into your water supply and lowering the quality of the water. Easily installed, the device remains buried and out of sight. They can also be used to convert your wet rainwater harvesting system into a dry system. Remember that regular maintenance and cleaning are required so that the device can continue to function efficiently.