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NDS 475 4 in. ABS Backwater Valve with Quick Flapper Seal

NDS 475 4 in. ABS Backwater Valve with Quick Flapper Seal

Brand: NDS
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$154.57
$115.93
SKU 475

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The NDS 475 4 in. ABS Backwater Valve prevents sewer and drain backflow into basements and other low-lying areas. Designed for horizontal installation, it uses a quick-action flapper and elastomeric gasket to allow one-way flow while maintaining a watertight seal.

  • Material: Durable ABS construction resists chemicals and corrosion.
  • Seal: Elastomeric flapper gasket and neoprene access-cap gasket provide a reliable watertight seal.
  • Compatibility: Connects to 4 in. DWV pipe; hubs adapt to 2", 3", 4" or 6" systems with NDS adapters.
  • Access & Maintenance: Threaded hand-tight access cap and removable flapper simplify inspection and service.
  • Installation: Lightweight and economical; riser with cover can be cut to length. Arrows on the hub indicate flow direction.

As a cost-effective alternative to cast iron, the NDS 475 offers long-lasting protection and easy serviceability. Use appropriate solvent-cement fittings and inspect the valve periodically to ensure unobstructed operation.

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Frequently Asked Questions

What pipe size in inches does the NDS 475 fit?
The 475 connects to 4 in. DWV pipe. Hubs can be adapted to 2", 3", 4" or 6" systems with NDS adapters.
How should the backwater valve be installed for correct operation?
Install the NDS 475 horizontally with the flow-direction arrows pointing downstream. Use solvent cement where needed and hand-tighten the access cap.
Is the flapper removable for maintenance or replacement?
Yes. The quick-action flapper is removable and replaceable; the elastomeric gasket maintains a watertight seal. Inspect and replace as needed.
Can this valve resist corrosive or chemical exposure?
Constructed of ABS, the 475 is chemically resistant and a cost-effective alternative to cast iron in many drainage applications.