My 20-year-old 40-gallon gas water heater has always worked fine with no problems until recently it began leaking out of the plastic valve on the side. It leaked slowly for about 3 weeks. At first the leak was maybe a cup per day, increasing to about 3 cups per day. I had a container catching the water and emptied it daily. Then suddenly the drip stopped and it has not leaked for a month.
My question is, why would it leak, get worse, then suddenly stop leaking all-together? And do I need to replace it now or wait until it is working improperly? We have always had plenty of hot water in the house, and no other problems with it.
Thank you!

Diana:

I will tell you... 20 years is a pretty old water heater. Any name on it by chance.

They did not have plastic anything on water heaters 20 years ago.. ARe you sure valve was plastic.. Could it have been replaced years ago from brass one to a newer plastic one..

The valve that is leaking is the valve at the BOTTOM of the heater yes..

Answer questions and I will give you best answers I have... Mark

Marks done many more heaters than I have but here's my shot. At 20 years you are on borrowed time so that this lull as a opportunity to get another heater all prepped for installation. Change it now or wait for the leak to return, it likley will. This answer is based on that valve being the drain valve down at the bottom. If the leak is at the top It may be worth investing in a new pressure relief valve.

My water heater brand is American - it says Ameri-Glas Energy Saver Plus, and the date manufactured is 1/1984. The house was built 1987. The valve leaking is near the bottom of the water heater, and it's white plastic with threads on it, like for a hose to attach to. Does this information help?
Thanks again!

Yes it does... I know the brand. Good brand... but 24 years is just asking for trouble.

I agree with Bob (Ballenger)... I think this is a good time to consider replacing that water heater and be done with it for years to come.

Since this is an item most people don't buy more than once or maybe twice in a lifetime, I have no idea what is a "good" or "bad" water heater. I tried to research them on the Internet and some reviews were really bad - such as pilot lights that keep going out, etc. Can you give me any tips on how to shop for one or where to go? For instance, the one in my house is American brand... I have no idea who might sell that brand. I assume most people go to Sears or Home Depot when buying a REPLACEMENT water heater.
Any tips for me? (Thanks so much for all your information so far! )

You are correct about HD and Sears as well as Lowe's and Menards. They don't all carry every brand but you can call in advance and ask if they carry American, White or Rheem. All good brands but I am sure others may also have their favorites. Buy the longest warranty model you can afford. They do not need replacement once or twice in a lifetime anymore.

24 years is just asking for trouble. I agree with Mark. I believe 8 years is the average water heater life. However, what happens when you have a water that's built into the kitchen counter top and cabinets? I'll tell you whot! Ya baby that sucker along so you don't have to remodel your kitchen. I have a Kaplan 30 gallon, incounter, single element water heater hat came with the house 54 years ago. The boiler drain has been brought through a outside wall and I flush it out every two weeks. I set the tempurture at the hotest I could stand it in the shower so I don't have to temper it with cold water. Please don't tell my heater that that 24 is too old. It still thinks it's a kid and I haven'tb the heart to correct it. Cheers, Tom