[pdqaltair]

This is a little off-topic, since the methods are not directly applicable to sailboats, but some of it is and there is good food for thought throughout.

In a nutshell, though careful selection of water sources, treatment to make the water biologically stable (nothing for bacteria to eat), and world-class maintenance, they do not chlorinate in most areas, most of the time.

http://www.jwrc-net.or.jp/aswin/symposium_archive/images/data/009_inv_es_Gertjan-Medema.pdf

How much of this can be copied by sailors? Where (certainly not world-wide)? Is that enough?

 

[pdqaltair]

Well said.

The vent issue is well taken; strange that though the US plumbing code requires at least a bug screen (16 mesh), few boats even have this. Easy fix, as discussed on this forum.

Regrowth, for example through the vent, will occur, but the odds of the dust being pathenogenic are remote. Certainly any bacteria can be important for food processing and medical applications, but it won't be fecal contacted. The risk would be the of growth of the few surviving pathenogens, but most evidence suggests that they don't really like to regrow outside of a host. Certain imuno-compromised individuals are at risk, but not most folks.

How much of secondary disinfection (the chlorine you taste) is for control of pathenogen re-growth (little, I suspect) vs. in leakage of sewage (not an issue on boats; the Netherlands focus on good maintaince), bio-corrosion (not an issue on boats; the Netherlands focuses on bio-stable water and flow) and taste/quality issues (any carbon block POU filter would solve that)? Is secondary disinfection really needed on a boat, if the feed water was microbiologically safe (which it should/will be in the US)?

I posted the topic because the Netherlands' practice is an interesting and well-executed counterpoint to common practice.

 

[pdqaltair]

What passes for clean tap water around here is pretty bad as even the boiler gets up set and requires a water softener and filtration

No relationship, actually.

Hard water is actually provably good for people, and iron, air, and chloride are no problem.

 

[pdqaltair]

It is note, microbiologically safe, which is the same idea as pasteurized milk, aslong as it's consumed in a reasonable time, there won't be any bacterial growth beyond what your immune system can handle. That is to say, if the water is allowed to stand still for a significant period of time and at moderately high temperatures (as encountered on a boat sailing in summer), it can regrow it's bacterial load from the remaining bacteria.

Mitigating that would need either upping the standard for the fill water and insuring the system is clean, reducing the amount of time between fills or possibly ciculating the water through filters (but those themselves form a breeding ground). If you can't do any of that, secondary disinfection will still be necessary, either by raised chlorine values (which can then be carbon filtered out at dispense time) or UV systems (ozone is not realistic in a small scale setting, small scale ozon producing systems use UV for that....).

Comparing water to milk, in this context, is a clear false analogy. Even if no pathogenic bacteria grew in the milk it would be undrinkable due to curdling and lactic acid. An unrelated studied, but the reason food packaging and pharma standards are rightfully VERY different.

Lets start with at a different point with a different comparison; well-water or rain water that has not been exposed to fecal contamination, just environmental bacteria that were not associated with a human host. Though we can nit pick, it is well accepted that uncontaminated well water and rainwater (some interesting Australian studies) are safe without either chlorination or microbial barrier filtration. Surely this water contains some bacteria, but so long as the source water was low in bio-available nutrients and uncontaminated by fecal material (these assumptions are central to this thread), what grows is limited and basically harmless. IF the source water to about has been treated to be free of pathenogens and is ONLY contaminated with dust through the vent and some harmless bacteria in the tank, the water may become distasteful (the degree depending on the cleanliness of the system and the source water) but it won't contain cholera, gardia, or the like.

Not sayin' I would not chlorinate in may cases, but I'm not going to worry over whether my tank maintains a chlorine residual each day.