Water Heater Won't Start

You REALLY should have stuff like your furnace and water heater serviced periodically. There is debate on how often. AC / furnace once a year. Furnace only, every 2-3 years, or more if you are a neglectful type. And that should include the water tank and any other gas appliances
I am definitely guilty of minimal maintenance.

I've flushed the water heater once, and it ran clear. Luckily, never an issue other than last nights.
I clean the reusable filter on the HVAC twice a year. I've had a couple minor issues with it. I've been able to fix them. It's as old as the water heater.
We have a water softener on our well. I clean the injector every couple years. It's always clean. We have city water now, and only use the well for the sprinkler.

My vehicles are maintained to the max. I guess I use the old axiom,"You can sleep in your car, but you can't drive your house".

We built the house when I was about 45. I figured we'll have to replace all major systems (inc. roof) hopefully once. (Water heater, probably more:rolleyes:) It'll be 20 years old when I'm 65. At 85, it'll be my stepdaughter's "investment".