Call a pro. Only the part that controls the pilot light may be at fault, not the entire unit. Make sure there is nothing blocking the air inlets to the unit, or the vent to the outside.

Check for a draft.

Well, the unit has not been moved, nor has anything anywhere near it. So, I’m thinking, it’s not a draft or anything blocking the air.

An aquiantance that I knew as a child kept blowing out the pilot lights in vacant apartments 35 year’s ago, in winter. To burst the pipes.

I would not rule out sabotage.

How’s the wind outside? Listen for gusts down the chimney the next time you light it.

Get a pro, gas is not for amateurs.

True

The pilot light of my furnace in my last apartment kept going out. Maintenance came, cleaned the pipes and the area well, and voila! no more problems with the pilot light!

It may not be anything so disastrous that the whole thing needs replacing, but let the professionals determine that.

And the utility should check it out for free.

Can natural gas leave carbon deposits that clog up the gas inlet?

Probably needs a new thermocouple. They burn out eventually and if it’s not working it won’t stay lit. It’s a cheap fix but you definitely want someone who knows what they’re doing changing it.

My money is with @Lightlyseared It does sound like a thermocouple they are not hard to replace and not that expensive but you really should know what your doing,Go talk to a pro and they might talk you on how to replace it.
Or pay for the service call and tell them you want to be shown on how to replace it in case you have trouble in the future.

Agreed, thermocouple is a likely culprit, and it’s probably a sub- $10 replacement part.

If you’re inclined to DIY, you can find YouTube video how-to’s. I’ve done a lot of home & car repairs after watching YouTube instructions.

Come to think of it, if your water heater is from the era of pilot lights, there’s a good chance it is getting “long in the tooth”.

I vote old thermocouple. They are easy and inexpensive to replace.

Also if your unit is ancient you might try adjusting the flame. Sometimes they are set too low to save energy. Go for it. Splurge and spend the extra 3 cents per month by increasing your pilot light flame a touch.

Thanks for all your advice, jellies. Sounds like the service call will be more expensive than the part. But at least I won’t have to replace the whole unit. I hope.

I’ll put money on the thermocouple . $15.
Of course it will be different depending upon the model but the part should look something like that.
Please let us know the verdict.

How come your link says it’s $4.62?
They are not at all hard to replace ,just don’t kink the line ,and don’t over tighten it, I had a gas guy talk me through it and over the years have replaced a few on different hot water heaters, I always have one sitting in my tool box.

@LuckyGuy Thanks for your suggestion and link. I don’t see anything immediately obvious that looks like the picture. If it goes out again, I’ll check YouTube videos and see if it’s anything that I could attempt. If not, I’ll call a technician. Hopefully, it’ll indeed be just the thermocouple.
Thanks.

@SQUEEKY2 The prices varied for various models. I picked the highest price, $15, to show it was not expensive.
I used to keep a spare taped to the tank.

@2davidc8 Can you find the pilot light flame? Does it have a thermocouple sticking into it? You can decide if you want to tackle the job.

@LuckyGuy Yes, I can see the pilot light flame, but I don’t see anything sticking into it.

@2davidc8 Rats! Usually the thermocouple tip is sitting right in the flame. You might have something tricky or a small thermocouple sitting a little above it.
It is time to check the manual for your make and model. Far better to find out what’s needed before you need it.

@LuckyGuy The heater was instaled by the previous owner of the house. He didn’t pass along the owner’s manual. I“ll have to look for it online. Thanks for the suggestion.