Stinky Bubbly Hot Water

[asalotto]

Hello,

I haven't used the hot water in several months, and when I turned it on today it was stinky and bubbly (like it was carbonated). I ran it for a while, and it stayed the same (although I probably didn't empty the hot water tank). The hot water wasn't heated, I was just at the dock with no engine nor electric heating. The cold water appeared normal. Any ideas what caused this and how to resolve it?

Thanks in advance!
Anthony

 

[MikeHoncho]

Hydrogen sulfide built up in the tank due to decomposing materials would be my guess.

 

[JoeWhite]

Yes. It is due to not being used. The electric heating element inside the water heater combines with the chlorine that is added to the city water and produces the stinky gas and brown water, that is due to heating element rusting. Ask me how I know.
Fortunately you can clean the water tank.
Remove the drain valve and drain all the water. Remove the electric element to drain remaining water. Connect the input of water pump to a 5 gallon bucket of water and rinse and drain until water is clear. Reinstall element and drain plug and fill with 8 Oz of 7% chlorine with 5 gallon of water. Wait for 3 hours. Fill and drain with plain water.
I did that and now evertime I visit the boat I drain 1 gallon of hot water. This adds 1 gallon of fresh water which will prevent this chemical reaction.

 

[Don S/V ILLusion]

also check for a deteriorating anode in the tank which would cause what you described.

 

[Stu Jackson]

and now evertime I visit the boat I drain 1 gallon of hot water. This adds 1 gallon of fresh water which will prevent this chemical reaction.

Yes ^^^

Just get in the habit of using the hot faucet even if there's no hot water whenever you're at the boat. This has worked for me for 25 years.

There's this handy link, too:

Fresh Water System Recommissioning 101 - Peggie Hall's "Cocktail" Rotten Egg Odor hot water "rotten egg" odor

 

[JoeWhite]

also check for a deteriorating anode in the tank which would cause what you described.

Unfortunately there is no zinc included by default for most marine water heaters. The manufacturer of my water heater provides if asked for, but the drained valve must be replaced with the zinc bar, this means that the water heater can no longer be drained. So I decided against the zinc. Most other manufacturers do not include it, they said it was not needed.

 

[skunther]

Unfortunately there is no zinc included by default for most marine water heaters. The manufacturer of my water heater provides if asked for, but the drained valve must be replaced with the zinc bar, this means that the water heater can no longer be drained. So I decided against the zinc. Most other manufacturers do not include it, they said it was not needed.

My tank has no anode (Seaward s600), so I purchased one. I’d read you replace the drain faucet with the anode, and simply drain the tank by removing the anode, but that seems would be a bit messy compared to draining out of the faucet (with a section of hose attached). Has anyone worked out a better way to drain the tank when an anode has been installed in the stead of the drain faucet? Perhaps siphon out the cold water input?

 

[Skipper John]

Good news! They make anodes with built-in drain valves: https://www.amazon.com/Camco-11533-...lpcontext&ref_=fplfs&psc=1&smid=ATVPDKIKX0DER! Good luck...

 

[skunther]

Good news! They make anodes with built-in drain valves: https://www.amazon.com/Camco-11533-...lpcontext&ref_=fplfs&psc=1&smid=ATVPDKIKX0DER! Good luck...

Thanks for that. I wish I could find it, but I just watched a video showing an OEM anode after 16 mos (deteriorated and severely pitted) vs an aftermarket one with a valve and other metals after 2 years in the same water heater with barely any corrosion, meaning the aftermarket one was not doing its job. The valve on that one looks like it would help direct the outflow a bit, but not a whole lot compared to just opening the hole by removing a non valve type anode.

I think I’m going to go with the standard Whale anode for caution’s sake.

Is there a way to easily drain the system without going out the drain tap?

 

[JoeWhite]

The only other way to drain is to remove the water tank. Probably not a fist choice. You can disconnect the electric element to drain, but be prepared to catch 5 gallons of smelly water.