You may not think too much about your gutters and downspouts. But the water has to properly drain somewhere. Here are 5 facts about the impact of downspout water. 1) For a home with a 1000 square foot roof, 1 inch of rainfall feeds 623 gallons of water into the gutters and downspouts. If the roof empties into 4 downspouts that aren’t extended, than means each spout is dumping 150 gallons of water beside your foundation. 2) Rain barrels can be used to collect and reuse rainwater for watering gardens and hold about 50 gallons each. Recently the City of …