Legionnaries Disease - Overstated risk?

[Mark-1]

Since we have an excellent boating chemistry thread on the go I thought I'd try a Biology one...

Over years I've drunk water from marina hoses and kept water in tanks/bottles longer than I should. Not hurt me yet, although I did once find green weed growing in a 2ltr coke bottle filled with drinking water that had been left over winter and spring.

As I understand it legionnaires has to be inhaled as water vapour rather than drunk to cause illness so it's a risk for showers not from drinking water. Also apparently it has little effect on people with well functioning immune systems. Both true?

Presumably there are other biological toxins that can grow in standing water but legionnaires gets all the press.

Has anyone heard of someone becoming ill from the water in a marina hose or a boat tank left full of water for months?

How big a concern should it be?

 

[Gary Fox]

Since we have an excellent boating chemistry thread on the go I thought I'd try a Biology one...

Over years I've drunk water from marina hoses and kept water in tanks/bottles longer than I should. Not hurt me yet, although I did once find green weed growing in a 2ltr coke bottle filled with drinking water that had been left over winter and spring.

As I understand it legionnaires has to be inhaled as water vapour rather than drunk to cause illness so it's a risk for showers not from drinking water. Also apparently it has little effect on people with well functioning immune systems. Both true?

Presumably there are other biological toxins that can grow in standing water but legionnaires gets all the press.

Has anyone heard of someone becoming ill from the water in a marina hose or a boat tank left full of water for months?

How big a concern should it be?

It needs quite specific conditions and timing to become harmful, it's very rare, and is one of those diseases which is splashed all over the newspapers with feverish tales of grossly exaggerated deadly horrors and apocalyptic devastation... but it doesn't actually infect 99.999% of the general population...
( Sounds familiar for some reason..)
I know a chap, perfectly sane in other respects, who won't let his kids drink water from their hot taps, as he thinks they will be struck down by Legionnaires Disease. Sad really.

 

[capnsensible]

Risk analysis. There is virtually zero chance of getting galloping gut rot from bottled water. Yacht tanks on the other hand.....

By coincidence, I'm in the process of giving my yacht water tank a thorough refit. I did it once during the twenty years we lived aboard but obviously it had high usage. We have been ashore for a year now so the tank gets far less use plus had developed a minor leak. Anyway, the mould growing on the inside of the tank was not a pleasant sight. Even soaking and scrubbing with bleach didn't get it all off. Finally done though and leak fixed. I've given the interior a couple of coats (final one about an hour ago) of special rubberised paint designed for it. Yay.

Point being, if you have see no he inside of the average yacht water tank....I've seen a few, then you would always boil the water before consuming. Unless loose bowels are your thing. ?

 

[graham]

Having found a dead rat in a hot water tank once I would strongly recommend drinking only from the cold tap in the kitchen .

On the boat we usually wash down the boat for 5 minutes before filling the tank.

 

[johnalison]

It might be rare, like Weil's disease perhaps, but it is sufficiently nasty for strict measures against it to be justifiable. I agree that drinking marina water is not a problem, but I have followed the advice to run hose water for a minute before filling the tank for a long time. It makes sense to use the waste water for boat washing first, or take the hose from someone who has just used it., but I don't feel guilty at wasting a little water when this is necessary.

 

[Gary Fox]

It might be rare, like Weil's disease perhaps, but it is sufficiently nasty for strict measures against it to be justifiable. I agree that drinking marina water is not a problem, but I have followed the advice to run hose water for a minute before filling the tank for a long time. It makes sense to use the waste water for boat washing first, or take the hose from someone who has just used it., but I don't feel guilty at wasting a little water when this is necessary.

I think Weil's is a greater threat, especially from mooring lines. This is a quick rat-cam snap from my deck, last night.

 

[pvb]

I always add AquaMidi Tabs to my water tanks, every time they're filled. They've stayed clean and the water is safe. As others say, just let the marina hose run for a few minutes before filling the tanks.

 

[ean_p]

It needs quite specific conditions and timing to become harmful, it's very rare, and is one of those diseases which is splashed all over the newspapers with feverish tales of grossly exaggerated deadly horrors and apocalyptic devastation... but it doesn't actually infect 99.999% of the general population...
( Sounds familiar for some reason..)
I know a chap, perfectly sane in other respects, who won't let his kids drink water from their hot taps, as he thinks they will be struck down by Legionnaires Disease. Sad really.

To be fair to your friend a lot of hot water systems have an open / un sealed tank usually sited in a loft or attic area and so may be contaminated with all manner of stuff you'd not want your kids to ingest.

 

[Poignard]

To be fair to your friend a lot of hot water systems have an open / un sealed tank usually sited in a loft or attic area and so may be contaminated with all manner of stuff you'd not want your kids to ingest.

I had a tank like that when I moved in here. Dead insects floating about. It fed the bathroom cold taps.
Now I have a combi boiler I don't have a loft tank and I also had mains cold water run to the bathroom taps.

 

[capnsensible]

Apparently my blond highlights have been outed as white rubberised water tank paint. ?