How long is it safe to leave fresh water in tank?

[skenn_ie]

Originally Posted by LifesBetterWhenYoureBeating

Hi everyone,

I have 2 water tanks on my boat and a couple valves that let me choose

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That depends entirely on the quality of the water going in, did it get contaminated with something from outside, what was the quality of the water that was there before the refill, and what the tank is made of.


In theory, it should be OK for many months. Purely from a biological viewpoint, it is good practice to empty tanks completely a couple of times/year, adding "purifier" tablets when you start the refill, and making sure that nothing untoward gets in (seawater, oil etc).

[Bill_Giles]

We too have two tanks, we only use the water from them for washing, cleaning and cooking where the food is boiled. We keep two 5L bottles topped up from the marina taps for drinking.

[skenn_ie]

Camden tablets for wine/beer making, or purificatiin tablets from camping/outdoor suppliers.

[hzcruiser]

Did you check on older threat before?

https://www.cruisersforum.com/forums...nk-245614.html

Same here, I use Katadyn silver ions when filling the tanks, leave the water in them forever, then drink it through a good filter at the tap. No foul smell, no side effects.

Just make sure the water you put in is clean.

[Iains boatyard]

Originally Posted by Bruce K

I have lived most of my life on collected rainwater (as I am now). Neither me or any of my family have ever "treated" this water, no chlorine, no filter, just large storage in TOTAL darkness. Only treatment is to throw a bit of limestone or old
clean oyster shells in to stop any acidity. No one has ever had any waterbourne sickness, from new borns to oldies. The longer you can keep the water, the better it is. On my boat i collect rainwater diredt into the tanks which are totally dark, no filter. no chlorine. never a problem. Most of the problems about storage of rainwater are perceived problems.

I am with you Bruce good choice.
Recently found out The Bottled water industry is the world 5 th largest emitter of green house gases.
Also in my humble opinion one of the worlds biggest con games!

[Cwens]

Bleach kills (many) pathogens. It does nothing to remove chemicals that have leached into the water from tanks, hoses, and fittings, all of which are going to steadily increase in concentration the longer the water stands in the system. If you're living on tank water for extended periods of time as opposed to the occasional weekend, I'd be concerned, for example, about BPA and pthalates, particularly if anyone drinking the water was a woman of reproductive age or a child.

[hzcruiser]

Originally Posted by ChrisOwens

Bleach kills (many) pathogens. It does nothing to remove chemicals that have leached into the water from tanks, hoses, and fittings, all of which are going to steadily increase in concentration the longer the water stands in the system. If you're living on tank water for extended periods of time as opposed to the occasional weekend, I'd be concerned, for example, about BPA and pthalates, particularly if anyone drinking the water was a woman of reproductive age or a child.

Can you please elaborate how it matters who is opening the tap? I guess you mean it can be more harmful for them, maybe?

[Cwens]

Originally Posted by hzcruiser

Can you please elaborate how it matters who is opening the tap? I guess you mean it can be more harmful for them, maybe?

For old guys like me, things that interfere with the development of new tissue just aren't as relevant as they are to growing children or pregnant women. Endocrine disruptors aren't going to mess us up as badly because our bodies aren't trying to choreograph the delicate biochemistry of reproduction. Things that interfere with orderly cell growth aren't as harmful because we aren't building new cells nearly as fast; things that interfere with brain growth not as big a deal because we're done building out our nervous systems; overall the tissue that we are building doesn't need to last us as long; we don't have as many years left for cumulative toxins like heavy metals to pile up in our bodies.

[hzcruiser]

Originally Posted by ChrisOwens

For old guys like me, things that interfere with the development of new tissue just aren't as relevant as they are to growing children or pregnant women. Endocrine disruptors aren't going to mess us up as badly because our bodies aren't trying to choreograph the delicate biochemistry of reproduction. Things that interfere with orderly cell growth aren't as harmful because we aren't building new cells nearly as fast; things that interfere with brain growth not as big a deal because we're done building out our nervous systems; overall the tissue that we are building doesn't need to last us as long; we don't have as many years left for cumulative toxins like heavy metals to pile up in our bodies.

I get where you're coming from. Not sure though if the mentioned pathogens would accumulate in a tank only because it's been sitting there for an extended period.

[Iains boatyard]

Bleach is a deadly chemical so ….. I am happy with my rain water constantly refreshed filtered in and out no bleach.
Sadly our environment is now polluted with many un healthy things. Not just visible plastic.

[rslifkin]

Originally Posted by ChrisOwens

Bleach kills (many) pathogens. It does nothing to remove chemicals that have leached into the water from tanks, hoses, and fittings, all of which are going to steadily increase in concentration the longer the water stands in the system. If you're living on tank water for extended periods of time as opposed to the occasional weekend, I'd be concerned, for example, about BPA and pthalates, particularly if anyone drinking the water was a woman of reproductive age or a child.

That's where good filtration comes in. Carbon filters can remove BPA and a whole lot of other stuff (with adequate contact time, so you need decent size filters even for low flow rates).

[h2o_snow]

Originally Posted by MicHughV

Your tank water lines are probably clear plastic hose somewhere inside the boat.....might be worth it to inspect these to see if you see any residue, or other contaminants.

Yes, it can get nasty in there. I was quite surprised re residual mold when we first purchased the boat. Put a cleaning port in our poly tank.

[Ike]

I''l tell you two stories. First: I served in the Coast Guard for 20 years. When I was on ships we would check all the supplies in the life rafts annually. Contained in those rafts were cans of water about the size of a large soda can. We checked each of those by simply slapping the end of the can. If it clicked the water was good. If it didn't click the can had leaked and it got tossed. Some one asked the question, how do you know the water is good. The chief said I''ll show you and he promptly opened one of the good ones and drank it. This was in the mid 70's. The date on the can was 1945. He never had any ill affects.

Second: My wife and I lived in our motorhome for 17 years. When we bought it new we sterilized the water tank. I added a filter at the inlet that removed rocks, gravel etc, because the water in RV parks is sometimes full of sediment. At the sink we had a Brita Filter. We used tank water when on the road. We used local water when in RV parks. We flushed the tank at least once a year. (sometimes a little longer because I forgot to do it. )

We never had a problem with drinking water. Once when the last RV park we stayed at had some issues with their water pipes, we actually bought bottled water for drinking and cooking. We traveled all over the country from Washington to Key West, New York to California and we hit all the lower 48. But not once in 17 years did we have any water make us sick, It never tasted foul or smelled. Fill those tanks and use it.

[Traveler7]

Originally Posted by malbert73

Install a high quality filter and then drink away out of your tanks. I use a seagull but there are cheaper ways to do it out there. Not just carbon but also filters out microorganisms

Seagull is awesome! I used to sell water filters and General Ecology always seemed the best choice if weight was not a problem.

[noelex 77]

The solution we have adopted is to use a “day” water tank.

This is a small 60L 316 stainless steel tank with a short hose lead to a seperate faucet in the galley. This is what we use for all our drinking water.

The watermaker output first feeds this tank, before it overflows into our main tank. We also use this tank for rinsing the watermaker (thereby ensuring there is no chlorine even if the carbon filter fails).
Given its small volume, most of the water in this tank is at most a couple of days old. The tank is also easy to clean out.

Using this "day" tank means we don’t have to add any chemicals, nor does in need any filtration.

It is an idea that could be retrofitted to many vessels.