The Watts GRD-640 is a stainless-steel metered overflow drain designed for green roof and planter applications where controlled secondary drainage is required. Its epoxy-coated cast iron body provides long-term durability, while the perforated stainless-steel gravel guard with secured solid cover helps prevent debris and ballast intrusion. The ABS standpipe includes a 5/8-inch orifice to regulate overflow, and the drain comes standard with a no-hub outlet, with a push-on option available.

Key Features

• Intended for metered overflow in green-roof and planter drainage systems

• Epoxy-coated cast iron body for corrosion resistance

• ABS standpipe with 5/8-inch orifice for controlled relief flow

• Perforated stainless-steel gravel guard with secured cover to block debris

• Standard no-hub outlet, with optional push-on connection