Hart to Hart collects from a roof so huge that it requires a 50 gallon roof washer. Instead of using piping for the roof washer, a barrel was used. A 50 gallon roof washer made of piping would require about 33 feet of 6 inch diameter pipe or 76 feet of 4 inch diameter pipe. Once the roof washer is filled, water enters the two 300 gallon tanks. Because there is so much water coming into this system, the overflow pipe splits off and waters two different areas of the garden.