Gasoline smell in rarely used pipe.

[pasadena_commut]

Last week the sink in our garage started dripping like crazy, the water was cold to the touch. It has separate hot and cold water valves which are joined by a an odd set of connectors outside the wall to the faucet. Anyway, this weekend pulled the cold stem, which is the only side we ever use, and found it needed an "OO 1/4S" washer. Of course I did not have any but was able to locate one without too much trouble locally. Replaced it and the faucet still leaked. So it had to be the hot side, even though the water was cold. Keep in mind that neither my wife nor I could remember the last time we turned that side on. Opened it up and it stank like gasoline, or at least some other petroleum based product. This is odd since it splits off from the hot water line to the washing machine, although I cannot say where since it is in the wall, and there is no odor in the washing machine (nor for any other water line in the house). Once the stem was out the water was turned back on briefly to clear the line, which spat out quite a bit of rust and rust colored water (the house still has original galvanized pipe), as well as a brass washer screw which had been in there who knows how long. There was still a washer screw on the stem, somebody must have dropped that extra screw in there ages ago. Replaced the washer, the leak went away, and the smell was gone too. Turned it back on hours later and still no smell.

The thing I don't understand is where that smell came from. Some odd chemical reaction between the rust, the water, the brass screw, and the rubber maybe???

 

[Diehard]

Well the main thing, the smell didn't return.
How long have you lived there and have you ever used the hot water side?
Are you sure it was more petroleum based type smell as opposed to say septic (rotten egg) smell?
Potable water has been known to smell septic after being stagnant for long periods of time.Googled this statement up...
"Hydrogen sulfide is the gas most likely to cause this smell. It is commonly caused by bacteria that forms in your hot water heater when it is run at low temperatures or turned off for a period of time. ... At 1 PPM it will smell musty, and at 1-2 PPMs it will smell like rotten eggs."

 

[pasadena_commut]

Not Hydrogen Sulfide - I know that smell. Definitely a petroleum odor. We have been in the house 23 years and have used that hot water valve occasionally, just not in a very long time.

 

[Diehard]

Not Hydrogen Sulfide - I know that smell. Definitely a petroleum odor. We have been in the house 23 years and have used that hot water valve occasionally, just not in a very long time.

Well a real mystery!
My first thought, being located in a garage where gasoline is know to be present, was possibly a case of back siphonage. A hose connected to a faucet that was at some point immersed in a petroleum product and was siphon by any possible means, such as drainage of the hot water tank, or other possibilities.
But you would likely remember a circumstance that could have resulted in something like that, even if you were not aware of it happening at the time.
That's why they typically have vacuum breaker faucets in these environments.

 

[Jamesplumbing06]

Well that’s highly unlikely. True but unlikely. Not to degrade you but who sticks a water hose in gas. At this point we are working on a memory. A memory that has been overshadowed by the constant thought of gas. So now the brain is swearing it was gas. Nothing we could say will change that now. Except maybe. Old gas doesn’t even smell like gas. So if it had been awhile then you would’ve smelled rotten dirt and diesel. Rotten water and steel stinks. Bad. Use the outlet every week. Just to get fresh water running thru.

 

[Diehard]

Well that’s highly unlikely. True but unlikely. Not to degrade you but who sticks a water hose in gas. At this point we are working on a memory. A memory that has been overshadowed by the constant thought of gas. So now the brain is swearing it was gas. Nothing we could say will change that now. Except maybe. Old gas doesn’t even smell like gas. So if it had been awhile then you would’ve smelled rotten dirt and diesel. Rotten water and steel stinks. Bad. Use the outlet every week. Just to get fresh water running thru.

I never knew that!

 

[Jamesplumbing06]

Last time I was called for gas smell. It was coming thru a “heated basement “vent. Just an open register in floor to let wood stove heat up in house. Ended up being a car battery sitting on concrete left on charger.
That’s not relevant but just reminded me.
Next yard sale you pass with a small engine machine. Open the gas can. That’s what old gas smells like. And don’t buy that machine. Lol

 

[pasadena_commut]

That's why they typically have vacuum breaker faucets in these environments.

The faucet looks a bit like that but doesn't have a breaker. Also the lateral pieces are oddly cobbled together to attach the faucet part to the valves. In any case, no siphon of any sort was ever attached to it.

I recall now that a couple of years ago when changing the pressure relief valve on the hot water heater (which is far away, on the other side of the house, in a utility closet) the threads were soaked with Liquid Wrench for a while before unscrewing it. A drop or two might have landed in the hot water. That lubricant has a similar petroleum smell. Hard to imagine any mechanism which would have concentrated that on the other end of a ~50ft pipe which was not used...