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
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Intended for metered overflow in green-roof and planter drainage systems
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Epoxy-coated cast iron body for corrosion resistance
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ABS standpipe with 5/8-inch orifice for controlled relief flow
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Perforated stainless-steel gravel guard with secured cover to block debris
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Standard no-hub outlet, with optional push-on connection
