BACKGROUND: Over the past few months the hot water is running out more and more quickly, on my Rheem Guardian Fury 22V50F1 gas water heater installed in June 2007. For the first five years since installation, it would take about 30 minutes of continuous running of the upstairs shower bath for the hot water to exhaust, with water temperature set to 130 degrees. Starting a few months back the output of hot water has been declining, and is currently taking about 15 minutes to run out.

QUESTION: Will appreciate advice on what to do. Will it be cheapest to replace the existing heater ? The warranty runs out in June 2013. Will the warranty cover this problem ?