The water heater was purchased and installed 11/2013, however, the pilot won't light now? How can I fix it? It is Envirotemp water heater with a push botton igniter and a window to watch it light.

It is most likely the thermocouple

https://www.youtube.com/watch?v=xGQngzqrIEE

Has it been working and just stoppped?
Did the pilot light go out a lot ?
Has the gas been turned off recently?

Here's a good read for some insight.

Troubleshooting Pilot Light Problems in Gas Water Heating (http://www.home-water-heater.com/troubleshooting-pilot-light.html#Pilot_does_not_light)

Is it still under warranty? Find out for sure BEFORE you go messing around. Consult your paperwork, or call the people you bought it from, or the manufacturer.

Does it light the pilot and then go out? If so, you are not holding down the button long enough or the thermocouple could be bad or the flame is not hitting 3/8" on the tip. You can test the thermocouple with a tester to see if it is putting out enough power to keep the holding coil pulled in. It's old enough to have a thermocouple go bad, but most last much longer. The flame may not have been set properly when it was first installed; therefore, it had a short life. Make sure to adjust it right if you have to replace it.