Expected life by type
A gas storage tank's life is bounded by its steel tank and glass lining. With anode maintenance it commonly reaches around 8 to 12 years, and most carry a 6- or 10-year tank warranty without labour; once the tank body leaks, the unit is replaced, not repaired. A tankless unit has no stored volume to corrode in the same way, and FortisBC states tankless water heaters have a 20-year life expectancy, almost twice as long as storage tank models.
Those are planning figures, not guarantees. Water chemistry, usage, installation quality and maintenance move the real number in either direction, which is why the history of the specific unit matters more than the average.
What shortens life
On a storage tank, the sacrificial anode is the main lever. It corrodes instead of the tank lining, and once it is consumed the tank itself starts to go. Bradford White's manual calls for the anode to be inspected every two years and replaced when depleted, and more often with softened water. Sediment build-up that is never drained also shortens life by overheating the bottom of the tank.
On a tankless unit, scale is the main threat. Rinnai states that lime damage is not covered by warranty and that hard water needs more frequent flushing, which is why annual descaling is a condition of the heat-exchanger warranty. A fouled inlet filter and a blocked condensate trap are lesser but recurring issues that are corrected at service.
Finding the age of a unit
The rating plate carries the model and serial number, and the serial usually encodes the manufacture date, but the decode rule differs by brand, series and era. This site's serial-number-age tool records the serial and explains the plate, and it deliberately declines to print a manufacture year until the decode rule is verified against the manufacturer's own published rule for that brand and series.
Installation paperwork or a service record is often more reliable than a decoded serial. Where neither exists, the visible condition of the tank, the fittings and the vent, plus the repair history, inform the replacement conversation more than a guessed year.
Maintenance that extends life
For a storage tank, the maintenance schedule is anode inspection, an annual relief-valve check and sediment draining. For a tankless unit, it is annual descaling plus a clean inlet filter and a flowing condensate trap. Both are described in the maintenance schedule guide with the manufacturer intervals.
None of that is do-it-yourself work on the gas side. The checks that involve gas, combustion, the relief valve or the vent are done by a qualified technician, and this site publishes no instructions for them.
Planning replacement before failure
A tank rarely fails at a convenient time. A unit near the end of its expected life, or one that has needed repeated repairs, is worth planning around rather than reacting to: the replacement can be scheduled, the permit arranged, and the choice between a like-for-like tank, a power-vent tank or a tankless conversion made without the pressure of a flood.
A leaking tank body is the exception that cannot wait. Close the cold-water supply and the gas or power if it is safe to do so, then call. CANRO Heating & Cooling handles leaking-tank replacement and provides free written estimates for replacements across its verified Metro Vancouver coverage, with repair visits carrying a diagnostic fee that is credited toward the repair.