Protects Plumbing and Extends Water Heater Life – The Water Worker G-5W (2-gallon) and G-12W (4.4-gallon) thermal expansion tanks are designed to safely absorb excess water pressure caused by thermal expansion in closed-loop water heater systems. Prevents pressure buildup that can damage pipes, fixtures, and your water heater.

Heavy-Duty Steel Construction with Durable Inner Liner – Built with a robust steel shell and a polypropylene liner that separates the water from the pre-charged air chamber, these expansion tanks resist corrosion, cracking, and waterlogging—ensuring long-lasting performance in residential and light commercial water systems.

Pre-Charged and Ready for Easy Installation – Each Water Worker expansion tank is factory pre-charged for quicker, easier installation. The G-5W and G-12W models feature a vertical design and a 3/4" male NPT connection, making them compatible with most standard water heater setups. Installation is simple with basic plumbing tools.

NSF Certified for Potable Water Systems – These tanks are NSF/ANSI 61 certified for safe use in drinking water systems, making them ideal for residential water heaters. The butyl diaphragm ensures a tight seal and helps maintain system pressure without contaminating the water supply.

Reliable Performance – Water Worker tanks are proudly made and rigorously tested for quality and performance. Ideal for both traditional tank-style and tankless water heater systems, these thermal expansion tanks offer peace of mind with proven reliability in high-pressure environments.