Water heater won't light

You say there is no spark at all.

One thing you can check;

The wire (sometimes it's orange could be another color) coming from the igniter, has a plastic shield over the connection. That plastic shield can be pulled back or forward which ever is easier so you can check the connection to make sure you have contact from the igniter to the wire that goes to your burner/pilot to provide the spark. Sometimes they work their way loose a little bit, thereby not giving you any spark at all. Unplug it and plug it back in, make sure it's making a good contact.

Make sure the igniter wire is in good shape. Check and make sure wire has no cracks, pinched, bare, or broken off from the metal probe that provides the spark.

If the wire is plugged in and making good contact, in good shape all the way to the metal probe, and you still are not getting any spark at all, then it's probably a bad igniter. They are about 5 or 6 dollars at a local hardware or plumbing supply store, and are easily changed out. They don't usually go bad, but they can over time. Usually it's the wire that goes bad from age. Take the old igniter and wire with you so you can show the parts person what you need.

If you feel comfortable enough to manually lite it the old fashion way, with a long match, you can try that to see if it fires up. Be very careful.

If you are getting a spark then there is something else wrong somewhere and will go from there. At 13 years old, there are a couple other components that are likely getting ready to go bad.

Some pics of the water heater would help us troubleshoot it better.

Stay tuned, there will be others joining the post shortly.

your welcome, hope everything works out for you.

cleaning or replacing the thermocouple should do the trick. While you have everything all apart, you should give it a good cleaning as well.

additional tips;

You should also vacuum any spider webs, dust, and dirt away from vent and filter area as well. usually located at bottom some where. Make sure you are getting proper air circulation to burner/pilot area. A lot of vaccums/shopvacs have a long nozzle to reach inside the burner compartment.

A lot of people forget that the water heater should be cleaned and flushed out at least once a year. Most people make sure their boiler/furnace is serviced and cleaned, but forget about their hot water heater. That to should also be cleaned and serviced yearly.

A lot of times, especially after 13 years of service, filters and screens get clogged up and they can also cause the pilot not to stay lit. Probably just needs a real good cleaning.

Sounds like you're on the right track. Let us know how it worked out for you, if you need anymore guidance, or still not remaining lit.