Every brand has a standard 6-year warranty model. Higher-priced model options can give another 2, 3, 4, or 6 years of warranty. The max warranty is 12 years. All tank-type heaters will leak eventually, and 12 years is the upper limit of any metal storage tank. There are two primary reasons a manufacturer can extend its standard warranty coverage on a storage-tank water heater: -Interior Tank Lining: Modern hot water tanks are made of steel but are coated with lining. This lining is typically made of glass, enameled porcelain, or another hardened proprietary material. This lining serves as a layer of protection from rust, corrosion, scale buildup, and other contaminants in the water. However, it will eventually start to erode, becoming part of the sediment buildup in the bottom of every tank water heater. -Sacrificial Anode Rod: An anode rod is a long metal rod that is coated with a proprietary blend of base metals such as aluminum, magnesium, zinc, or another alloy combination. Every tank water heater has an anode rod inside, and sometimes more than one. Magnesium rods tend to be more expensive, but they are also more effective. The purpose of the anode rod is simple: self-sacrifice. This part is more reactive to the various corrosive elements and minerals in our North Texas water. Essentially, the anode rod attracts and reacts with these benign but corrosive materials, which means it gets eaten away first—before the lining and steel tank.