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

[skipperpete]

Originally Posted by garyfdl

Not sure where your hearing that, but I would say its a gross overstatement.

Flint, Michigan springs readily to mind and at Las Vegas, lake Mead seems to be problematic.

[garyfdl]

Originally Posted by skipperpete

Flint, Michigan springs readily to mind and at Las Vegas, lake Mead seems to be problematic.

Yeah... Flint and Vegas comprise less than .002% of the US population.

As to Lake Mead, that's a climate change/drought issue. But I guess that's not something Aussies worry about though... as long as the Great Northern and Carlton holds out.

But I am flattered that so many Aussies are concerned about our 'rampant drinking water problems'.

By the way, how's the Darling Baaka River doing these days?

[sailorboy1]

Originally Posted by Sailorichiban

For years I added vodka to my tanks , bought it by the gallon, definitely improves the taste!
Probably a good lesson; always maintain situational awareness.

unless you add enough to be 40 proof/20% alcohol all it would do is become a biological breeding tank

[SailingHarmonie]

So much passion… so little data and science.

Someone stated that they don’t like RO water because it has “too much sodium.” My RO unit produces water with 400ppm TDS. Let’s assume all of that is sodium chloride. If you drink four liters of water a day (which you probably don’t) that is about 0.6 grams of sodium per day. That should be well tolerated even by someone on a low sodium diet, which is typically between 1.5 and 2.3 grams a day.

There are a number of different water quality issues that a boat owner needs to be aware of. The biggest issue is contamination with pathogens, i.e., bacteria, viruses, or parasites that can make you ill. These can be introduced by taking on contaminated water sources, typically poorly managed local water systems that are cross contaminated with sewage. This can also come through an RO system that uses contaminated feed water. Theoretically an RO membrane will not pass viruses or other pathogens, but desalination membranes are not perfect, and the seals between product water and sea water also might not be perfect.

By far the best way to deal with pathogens is chlorination of the tank water. Properly done, it will kill everything. People taking on suspect water in places you would not drink the water can chlorinate to safety.

If you make RO water in places far removed from sewage contamination, you do not have to worry about pathogens. Clean ocean water does not carry human pathogens.

An important thing about pathogens, if you don’t put them into your tank, they don’t appear there. They don’t grow there. If you keep sewage away from your potable water, it stays potable. Dangerous viruses, bacteria and parasites do not grow in your tank, they are put in there with the incoming water.

The next water quality issue is chemical contamination. This varies all over the map. It generates far more fear than it should, very, very few places have water that is dangerous to health from chemical contamination, but it does happen.

Carbon filtration (properly done) will remove SOME contaminants, but especially as done “at home” is very unlikely to be reliable. For many contaminants it does nothing. The only solution here is to know and trust your source. I honestly do not understand why people feel they can trust industrial bottled water more than properly treated municipal water, certainly both have had quality issues over the years. But it’s an emotional issue, not a rational one.

RO water from clean ocean water will not have any issues here.

The last quality issue is palatability. Does the water look, smell, and taste acceptable to the users. Water that tastes fine can be seriously contaminated, and water that tastes terrible can be perfectly safe. Chlorine can eliminate SOME taste issues, but at a cost. Water that has a lot of organic material when treated with chlorine can result in the production of chlorinated organic chemicals that have their own health risks.

Things that grow in the tank are not pathogens. They will not make you sick. They might make the water yucky, however. To avoid make your water taste bad, keep organic material out of the tank. It is food for bad tasting things. Keep your water out of the light. Keep the tank clean. Dirt grows stuff.

Water that has been properly chlorinated, and RO water, come in with very, very low organic carbon levels. Rain catching can wash a fair amount of dirt in to the tank, and will result in water that “goes bad” sooner if it is not chlorinated.

If you chose to chlorinated your tanks, get, and use, residual chlorine test kits. They are important! Water that has a lot of organic carbon in it will chew up the chlorine, and leave you with nothing to actually kill pathogens. A distinct chlorine taste can be the result of too little chlorine, not always too much. You don’t know unless you test. It it easy and cheap.

Oh, one last thing, if you have fresh water flush on your toilets, please, please, have a proper air break between the bowl and the fresh water supply. A direct connection is just gross. And dangerous.

[AKA-None]

Two things
Not sure you can kill something that isn’t technically alive re viruses

While working on a German ship once I asked about getting some water to drink and was informed they didn’t drink water as they couldn’t tell if it was safe so they bought beer by the pallet

[garyfdl]

Originally Posted by AKA-None

they didn’t drink water as they couldn’t tell if it was safe so they bought beer by the pallet

That's as good an excuse as any.

[PirateFoxy]

Originally Posted by Chotu

I bet I’m going to freak a lot of people out with this post.

I use the sewer lines. The ones that say "do not use" next to the black water dump area. I don’t even care. Ha ha ha. That’s how much faith I have in my bleach treatment.

when I go dump the tanks with an RV, I use the same source everyone uses to flush out their tank. Many times that’s the only source of water available.

I let it run a minute. So there really can’t be much in it. But then I use bleach in the tanks and it gets rid of any microorganism that may have made it.

have never had an issue doing this.

with water at the dock I think the bigger danger is not biological. It’s that it sits in the hose for too long or sits in the plastic plumbing that comes from shore to the dock. So you just have to let that run until you feel the water temperature change. So you’ve got something from land rather than something that’s been sitting in a hot plastic pipe all day.

but even then, the carbon filters take out the leaching plastic.

The system is pretty failproof. Bleach the tank. Filter the water. Not much can go wrong. Been doing this for like 30 years.

I haven’t lived in a house in most of that time.

You and my SO are like long lost twins or something, he does the same thing. Only with our designated water hose, though. He won't use a random hose just sitting there with who knows what on it.

[Chotu]

Originally Posted by PirateFoxy

You and my SO are like long lost twins or something, he does the same thing. Only with our designated water hose, though. He won't use a random hose just sitting there with who knows what on it.

Absolutely! You never know what the other hose was used for. I only use my own hose. Definitely.

[valhalla360]

Originally Posted by AKA-None

Two things
Not sure you can kill something that isn’t technically alive re viruses

While working on a German ship once I asked about getting some water to drink and was informed they didn’t drink water as they couldn’t tell if it was safe so they bought beer by the pallet

I'm not sure if the proper term is "destroyed" rather than "killed" but yes, you can. Not that you want it in your drinking water but simple soap & water can destroy many viruses as it strips the lipid coating on the surface.

Drinking beer is centuries old. Before people understood how to obtain clean water, beer was the most reliable thing to drink. Basically liquid bread.

[rslifkin]

I agree with always flushing the water lines on the dock, especially if they don't see a ton of use. I give it a couple minutes to flush, then put the filter on the hose and flush through that for another minute or so before starting to fill the tank.

[JPA Cate]

Someone above questioned that US waters were slowly becoming more jeopardized. Here's a link to an EPA report: https://www.epa.gov/report-environment/water It is only one of the references under Simi 60's link.

This is not a case of Ozzies bashing the US, imo, but more that people who live here are highly concerned with the quality of their water supplies, and the concern spreads to other cruising destinations, as well.

One needs to learn where such water degradation occurs, and what is the stuff of it. We have the ability to detect far lower concentrations of things than will hurt us, but we still don't know the long term effects.

Our own Boatman 61 had some serious problems on a delivery because he trusted the town water somewhere in FL. If one forms the habit of routinely chlorinating and filtering the drinking water on the boat, then your habit protects you.

Ann

[Stewie12]

When you buy bottled water you would be amazed as to how old it is.

[Pathfinder]

Grab a copy of the Practical Sailor's booklet, Onboard Water Treatment,
Storage, and Production. It is 69 pages and an invaluable guide to storing water on board. To keep the tanks clean and pristine, when not actually sailing, I drain them, wipe them clean and leave the filler openings uncovered so air can circulate.

[S/V Serenity]

Originally Posted by Jebtrois

You can purify and/or preserve the water with chemicals such as bleach and it will keep for a long time. However, to the extent that you can, I would turn the water over as often as reasonable through regular use. While the older water can be made safe so it won't harm you, it is certainly less palatable when it is otherwise pretty easy to refresh it.
JEB

Be cautious adding bleach to metal tanks. Corrodes them over time. Look inside the tank for white deposits.

[Hasbeen]

For 5 years the only water that went into my water tanks was caught off my foredeck awning. I never treated it, never filtered it & never had any problem.


They were fabricated in place polypropylene/fiberglass tanks if that is of any importance.