Electric hot water heater / Legionella bacteria concerns

[Stu Jackson]

Originally Posted by Smokeys Kitchen

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However, even when switched off, we routinely use the hot water tap to fill pots, pans, make coffee, fill sinks, etc. My point is that we do not let the water in the hot water tank stand; similar strategy to using our three separate water tanks.
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A good habit to get into.

[tarian]

Something Else to worry about on a boat , gas, bacteria , electric, batteries, you wonder does anyone go sailing, or in that has any one caught legionnaires from a boat , something else for the fear mongers , nothing better to do than worry about a minute problem you would probably die hitting an iceberg, it seems that this forum gets worse and worse by fear and silly questions
I only respond out of despair at the level of fear we create for ourselves, it is interesting as on the British boating forums these topics never come up, perhaps we only care about the real issues
Flame me, i ll be sailing drinking my tank water and showering from my heated calofier as I have for thirty years . And I only have a green tongue

[Franziska]

As we are not having inboard engines but will head south after our refit, we consider two things.

1)
Replace the standard 40l hot water boiler with an instant water heater.
2)
If we keep the boiler, add a largish thermosolar panel with a, at daylight, constant running pump which circulates water through the heating coil which is normally used for the cooling water">engine cooling water heat transfer inside the boiler.

[Brewgyver]

Originally Posted by NaClyDog

Yes, exactly. If water in the hot water tank isn't kept at a high enough temperature, it is possible for the Legionella bacteria to rear it's ugly head....

You make it sound like having tank water in the temperature range at which Legionella do best will actually CREATE an infection. It just doesn't happen. I would venture a guess that every water tank in every boat in tropical zones all over the world are in that range most of the time. Surprising that there are zero reports of cruisers getting Legionaries' Disease.

Millions of US homes have water heaters set BELOW 130 due to risk of scalding, yet no outbreaks.

This is on par with worrying about radiation in fish caught on the Pacific coast due to Fukushima. There's more radiation in a banana.

[Brewgyver]

And, PLEASE!!!

It's called a water heater, be it electric or gas fired. NOT a "hot water heater."

[Stu Jackson]

Originally Posted by tarian

Something Else to worry about on a boat , gas, bacteria , electric, batteries, you wonder does anyone go sailing, or in that has any one caught legionnaires from a boat , something else for the fear mongers , nothing better to do than worry about a minute problem you would probably die hitting an iceberg, it seems that this forum gets worse and worse by fear and silly questions
I only respond out of despair at the level of fear we create for ourselves, it is interesting as on the British boating forums these topics never come up, perhaps we only care about the real issues
Flame me, i ll be sailing drinking my tank water and showering from my heated calofier as I have for thirty years . And I only have a green tongue

Sometimes such a basic question comes up that begs belief, or disbelief.


It's like someone questioning gravity.


For not the first time.


Yeah, begs belief...

[GordMay]

Legionella, the bacterium that causes Legionnaires’ disease, occurs naturally in freshwater environments, like lakes and streams. Generally the low amounts of these bacteria in freshwater do not lead to disease. However, Legionella can pose a health risk when it gets into water storage systems.
To do this, Legionella first has to grow (increase in numbers). Then it has to spread through small water droplets (aerosolization) that people can breathe in.
After Legionella grows, and multiplies, in a water system, water containing Legionella then has to spread in droplets small enough for people to breathe in. People can get Legionnaires’ disease or Pontiac fever when they breathe in small droplets of water in the air that contain the bacteria.
Less commonly, people can get sick by aspiration of drinking water containing Legionella. This happens when water accidently goes into the lungs while drinking.

So, treated water (chlorinated muni', or R/O) is highly unlikely to contain Legionella, and our storage tanks aren't likely large enough to retain water long enough to grow significant numbers of bacterium, to cause illness.

[Franziska]

Thanks Gord.

Sounds like the main risk is more the warm shower than the galley.
Surely it's not wrong to be careful and keep water supplies clean.
Be it with silver iodine, some bleach or carbon filters.
No need for panic though.

Originally Posted by GordMay

Legionella, the bacterium that causes Legionnaires’ disease, occurs naturally in freshwater environments, like lakes and streams. Generally the low amounts of these bacteria in freshwater do not lead to disease. However, Legionella can pose a health risk when it gets into water storage systems.
To do this, Legionella first has to grow (increase in numbers). Then it has to spread through small water droplets (aerosolization) that people can breathe in.
After Legionella grows, and multiplies, in a water system, water containing Legionella then has to spread in droplets small enough for people to breathe in. People can get Legionnaires’ disease or Pontiac fever when they breathe in small droplets of water in the air that contain the bacteria.
Less commonly, people can get sick by aspiration of drinking water containing Legionella. This happens when water accidently goes into the lungs while drinking.

So, treated water (chlorinated muni', or R/O) is highly unlikely to contain Legionella, and our storage tanks aren't likely large enough to retain water long enough to grow significant numbers of bacterium, to cause illness.

[NPCampbell]

Originally Posted by Smokeys Kitchen

Is this only a concern when you allow the water in your hot water tank to stand and not use it for an extended period?

The primary concern with Legionella is if you are in a commercial building with poorly maintained wet exchange cooling towers. Most outbreaks outside of hospitals are tied to them. The name "Legionella" is due to it's discovery from infested cooling towers at an American Legion convention. The cooling towers act as both an incubator and a means of aerosolizing the bacteria to efficiently get it into your lungs.

Originally Posted by Smokeys Kitchen

We are on the dock at present - taking showers at the marina. The electric hot water heater is switched off, as we heat water for washing dishes, etc. on the stove. We occasionally turn the electric water heater on to just cycle it, allowing the water to get up to temp, then doing dishes or taking a shower on the boat.

However, even when switched off, we routinely use the hot water tap to fill pots, pans, make coffee, fill sinks, etc. My point is that we do not let the water in the hot water tank stand; similar strategy to using our three separate water tanks.

Don't know if this speaks to your question directly, but in 5 years of living aboard and doing this we have never had any issues with any types of growth in the water system.

You've probably had Legionella in your water and didn't know it. It's incredibly common in most natural water sources. It rarely affects healthy humans unless it's concentrated and aerosolized.

Giardia, on the other hand, does affect healthy humans. It doesn't need to be aerosolized, and is a frequent, if not the most frequent, waterborne concern.

[NaClyDog]

Originally Posted by Brewgyver

And, PLEASE!!!

It's called a water heater, be it electric or gas fired. NOT a "hot water heater."

In my part of the world, they are called hot water heaters. I really don't care what you think of that... the door is over there. Please show yourself out.

[Uncle Bob]

Hi, here in Aus there used to be a manufacturer that produced a water heater called Woody's that was not a pressure vessel, just a cylinder of water that was heated either by electricity or via the engine. It had an additional coil inside that the potable water ran through to be heated while it moved through the coil within the water bath. A very good system that has proven capable of delivering far more hot water than those systems that heat and store the water that is used, needing more heating for further hot water. I don't know if anyone else anywhere in the world produces a similar system but if available the system works well.

[svfinlandia]

Originally Posted by Brewgyver

And, PLEASE!!!

It's called a water heater, be it electric or gas fired. NOT a "hot water heater."

+1 !

You beat me to it. At the risk of being a smart a$$ - if it was already a HOT water heater you wouldn’t have to heat it anyway.
Always love me a little nuts when people called them a HOT water heater, but for me I guess it’s a short drive.

Al, S/V Finlandia

[Exile]

Coincidentally, I recently had a marine surveyor mention the prospect of Legionnaire's disease, except it was directed at condensate from an air conditioning system collecting in the bilge. I didn't follow up with him at the time, but perhaps the temperature of the condensate itself -- along with summer temps and/or warm climates -- produces fresh water within the temp range for potential growth as noted above. Another good reason to splash a bit of bleach into the bilge for those of us with boats that always seem to collect a bit of water down there.

[svfinlandia]

Originally Posted by NaClyDog

In my part of the world, they are called hot water heaters. I really don't care what you think of that... the door is over there. Please show yourself out.

Don’t mean to start a war here, but if they have always been called hot water heaters on your end of the world, then your end of the world has always been wrong. Calling them a cold water heater would be accurate but hot water heater says that you’re heating water that is already hot.
I know where the door is, but I’m still here.

Al, S/V Finlandia

[zstine]

Originally Posted by s/v Jedi

Every electric water heater for sale is safe because it heats water to high enough temperature, then the output is mixed with cold water by a thermostatic mixing valve so that no scalding hot water arrives at the faucets. I recommend an IsoTherm water heater.

not in the USA. our heater home heaters are set at about 130F. if the water is chlorinated, there is virtually no risk of Legionella.