A. Paul Fisette, director of Building Materials and Wood Technology at the University of Massachusetts Amherst and a JLC contributing editor, responds: Surprisingly, there is nothing in most building codes that prevents downspouts from being connected to a foundation's perimeter drainage system. But there should be, because this is a bad idea. Pipes used for perimeter drainage typically are perforated so that water can be carried away from the foundation. Additional water from a connected downspout would likely leak from the perforated pipe, saturating the soil near the footing. Also, if the perimeter footing drain ever fails or gets blocked, you run the risk of flooding the subsoil area.
Instead, downspouts should feed into a solid, nonperforated pipe that directs roof water far away from the house. This pipe should run independently from the footing drain.
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