Toilet Tank, Biscuit, 1.28 Gallons per Flush, Left Hand Lever

Gerber Viper® Toilet Tank – 1.28 GPF, Biscuit, Model GWS3859509

The Gerber Viper® GWS3859509 toilet tank delivers efficient water performance with a 1.28 gallon per flush rating and is designed to pair with compatible elongated or round front Gerber bowls. With its high-efficiency flush and durable vitreous china construction, this 12" rough-in tank is a reliable solution for light commercial and residential installations.

Product Features

• Flush Volume: 1.28 GPF high-efficiency design meets EPA WaterSense® criteria.
• Flush Valve: Outfitted with a 3" flush valve for enhanced bulk removal and quick tank clearance.
• Fill Valve: Includes Fluidmaster® 400A for quiet, consistent tank refills.
• Trip Lever: Side-mounted left-hand lever in a color-matched biscuit finish.
• Material: Vitreous china for long-lasting durability and resistance to staining or fading.

Specifications

• Model: GWS3859509
• Flush Rate: 1.28 gallons per flush (4.8 liters)
• Trip Lever Position: Left-hand
• Color: Biscuit
• Compatible Rough-In: 12-inch configuration

Installation Notes

This tank is designed for use with Gerber Viper® series bowls. It mounts using a standard tank-to-bowl connection with brass bolts and rubber gasket (included with select models). While installation is straightforward, proper alignment and gasket seating are critical to ensure a watertight seal and proper flush performance. Licensed plumber installation is recommended for compliance and reliability.

Contractor Considerations

• Jobsite Ready: Includes Fluidmaster fill valve and oversized flush valve for reduced call-backs.
• Water-Saving Compliance: Ideal for projects requiring WaterSense® certified fixtures to meet LEED or municipal efficiency standards.
• Replacement Flexibility: Compatible with existing Viper® system components for simplified field repairs or upgrades.