Here is a picture of my neighbors hot water heater. It is an A.O. Smith Natural gas with natural draft venting. There is a drip coming from the PRV pipe, sticking my finger in the pipe there was moisture present. I verified the age of the unit at 24 years old. I gave her a free home inspection and went through my Aging-In-Place inspection with her as part of my ongoing training. Though I wouldn’t recommend replacing a water heater for a dripping PRV, I know that she is on a fixed budget and recommended she start budgeting for replacement due to the age and hard water.
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Michael, welcome to InterNachi and the forum, where you come to exchange ideas and learn.
This is a teaching moment so please do not be offended by correction.
This is a water heater, not a “hot water heater”.
That is not a leaking PRV (pressure reducing valve). It is a leaking TPR valve.
The Temperature/Pressure Relief (TPR) valve on the water heater is a safety device that you should not over-look. Are you not concerned about why the TPR valve is leaking? The water heater may be over-heating. This can be caused by a failed thermostat or a heating element shorted to the metal tank or cabinet. A professional plumber should replace any failed thermostats or shorted heating elements.
In your case, its a gas water heater so you don’t have heating elements so it could be a failed thermostat or the TPR may have failed. Report the condition and recommend correction by a qualified plumber.
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Did your neighbor buy the water heater from a pawnshop?
Where is that flue exiting the home?
As a natural draft WH, (not a HWH), it should be exiting through the roof.
The photo makes it appear that it exits through a sidewall, which is not allowed.
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@mbond5 , another thing to consider that may help with the dripping TPR valve would be to recommend to also consider adding an expansion tank to absorb some of the water expansion when colder water heats up with a closed system…there are many threads on this and good info on the web. With no expansion tank on the cold water inlet in the picture, I would assume this may be a partial culprit to why the TPR outlet may be dripping and/or damp!
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High water pressure, often due to a bad pressure regulator, can also contribute or cause the TPRV to fail.
(Just curious you all, do you think it would be possible to get more unions in that flue pipe? 
)
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Hot water is defined as 110 degrees.
Most water heaters thermostats shutoff around 125-135 degrees.
Most thermostats come on well before the temperature of the tank drops to 110 degrees. Therefore it’s a both a cold water heater and a hot water heater. In fact, it spends most of it’s life heating hot water, not cold water.
From here it looks like the water heater TPR valve had evidence of leaking. The vent pipe was improperly installed and had inadequate clearance to combustibles. There was no obsvervable expansion tank, and the water lacked a drip pan underneath it.
Possible galvanized pipe used for gas pipe.
Have a qualified Plumbing Contractor make corrections as needed.
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Best advice out of everything mentioned above.
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There’s clearly signs of previous leaks on the floor and bottom plate on the wall to the right of the heater.
If an elderly person was living there, I would also mention the lack of a handle for the gas line shut off valve.
Agreed . The is something that is covered in MANY courses. It’s a safety feature that is possibly failing.
What did you use to take that picture? Looks like a lower resolution camera shot used with a flashlight for a flash. Makes it hard to see details in the picture when you zoom in. Do have any other pictures of this area? Especially the items others have mentioned? Flue pipe? Floor behind the water heater? Gas line and associated parts? Etc…? Was there a floor drain near by?
That is why I posted, thanks for the feedback.
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A few comments about the galvanized pipe not allowed for use with gas. Is this some local code I’m not aware of? Modern galvanized pipe is not none to flake like the old galvanized pipe did.
by who, exactly?
edit: just curious… you do have a valid point, by the way.
The average life expectancy of a gas fired water heater is 8 to 12 years.
Refer replacement immediately!
Insurance company many refuse any damage.
The inhabitants are at risk!
Rental will be the way to go on a fixed budget,
Gas fired water heaters can be consider one of the most hazardous appliances in a home.
igniting flammable vapors
CO
Explosions.
Gas-fired water heaters cause an estimated 1,961 fires each year, resulting in an estimated 316 injuries, 17 deaths, and $26 million in property damage for a total societal cost which may be as high as $395 million.
Food for thought.
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Unfortunately, 110°F is an ideal temperature for “Legionella bacteria, and other pathogens” to grow.
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wow, thank you. I expected there to be a definition for scalding water. I guess that’s pretty much what it means here.
interesting, the CDC defines hot water as 90*, in the context of aquatic facilities and swimming.
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There is one.
The CDC is loaded with misinformation.
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It’s also unfortunate that what kills us(i.e pain, burns, necrosis), also kills pathogens. While there are charts on exposure time, age, skalding and burns, it is generally accepted that water at 125 degrees is painful, as in yank your hand out painful. The problem is, Legionella can survive in 125 degree water for hours before it is entirely killed off. At 120 degrees it can be fat and happy for a very long time.
Water heaters are best served to be at least 130 degrees as nothing is going to last long enough to be an issue in that. This means that mixing valves are necessary unless you’re my grandmother. Every time she washed dishes I think she was making grandma sous vide. I couldn’t touch the hot water!
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