Hot Water System Selector You have told us: Your gas hot water system has an issue with no hot water.
Gas hot water systems are very reliable and we expect them to have a lifetime in excess of 10 years. They also come with long warranties, typically at least 5 years.
Roughly how old is your water system? (guess if necessary)
Depending on the age of your hot water system, warranty might still apply or it might even be more economical to replace it.