Water Heater Defects
Water heaters have an estimated lifespan of roughly 10 years, with high quality water heaters lasting longer. As they age and wear, there are many issues than can arise. Poor installations are also fairly common. Some issues are easily corrected and not immediate concerns. Others, such as problems with improper temperature and pressure relief valves, are much more concerning.
Missing shut-off valves
Backdrafting & venting problems
Improper TPRV installation
Excessive water temperature