keeping water drinkable... and knowing when it is not?

[bgary]

Are there tips and tricks for keeping tank-stored water drinkable?

I put about 10g each into my port- and starboard tanks a couple of months ago. Have used it on occasion to rinse things off, wash hands, etc. But.... wondering what kinds of beasties might be inhabiting those tanks has so far kept me from drinking it.

Now that the cruising season is here, I'd like to be able to. So.... should I flush out the tanks with something? keep them empty until needed? Keep them full? Treat the water with something?

Would welcome any tips. Not only for keeping the water potable, but knowing when it isn't. Yeah, if it comes out green or smelling nasty, I'd probably be able to figure that out, but if it "looks" clear and fresh... is it?

Bruce

 

[admirals barge]

keeping water drinkable

you can add chlorine bleach to the water. 1 teaspoon per 10 gallons of water. I use carbon block filters to filter out the beasties. my tank has a tee and one hose goes to the head and the other to the galley so I have 2 filters. I also use hand and foot pumps, but will work with pumps. don't buy regular carbon filters. they are carbon impregnated paper filters. if it gets a hole in it you would never know. buy a carbon block filter. its solid carbon and when it starts to clog up the water flow will decrease and when it gets to about 1/2 the usual flow its time to replace it. the small filters I think 3 inch are good for 2000 gallons...you can buy the canister in clear or blue and mount it in line with the water line somewhere convenient so you can get to the filter.. I hope this helps

 

[Loren Beach]

We have found that the water coming out of the tap can look good and some algae is still present in the tank and slowly clogging the little screen at the end of the end of the tap. Ick.

After the water sets in there for several weeks I can look inside and see little bits of green-yellow algae in the bottom area.
Since we clean out the tank with some bleach on a rag every fall and leave it dry all winter I really have no idea where this stuff comes from...


What I do is inspect the tank for clarity. Usually, if we are not using the boat (for overnighting) for, say, three weeks or four, I empty the tank and wipe out the interior with a clean rag. I copied another member's tank-emptying setup and have a small (cheap) centrifugal bilge pump with a six foot clear tube for routing into the galley sink, and a ten foot wire run to a 12 volt plug in. This allows me to empty all 38 gallons in a few minutes and saves a lot of run time on the spendy system pressure pump.

When I had a custom ss tank built for the boat it was spec'd out with six-inch screw-out ports to make inspection and clean out easy. If your boat does not have clean out ports I would strongly advise installing them in each tank, fresh water and the fuel tank as well.

It's great to have clean water coming out of our boat's taps like we take for granted in our homes, but this comes at a price in time and attention.

cheers,
Loren

 

[Christian Williams]

The former owner of my new boat put a Culligan water filter (designed for RVs) in the engine compartment next to the Racor. Very simple installation, and the carbon filter canisters are easy to change.

Never felt the need myself, but it's so simple I think I'll keep it.

 

[u079721]

I struggled with this too. I used to fill the water tanks when I commissioned the boat each spring, but I quickly found that the hot water went bad and smelled of sulfur bacteria after a few weeks. Killing the smell involved a shock treatment with chlorine bleach, followed by lots of rinsing. Once I was cruising each August for a month it wasn't an issue, since I was using up the water from the hot water want and bringing in fresh water with fresh chlorine.

So my eventual pattern was to leave the water heater bypass tubing in place and the water heater empty until the start of the cruise, with one tank partially filled for the occasional day trip use. Never once had an issue while cruising, just when you have the boat sitting at the dock not using the water.

 

[toddster]

It's pretty difficult to keep water potable over long periods of time in vented tanks. I wouldn't even try, unless you are using them every day. I'm pretty dubious about the water available on our docks to begin with. For day sailing, I just use tank water for cleaning. I keep a case of bottled water under the settee for drinking. If I were headed out for a week or more, I'd put the effort into cleaning the tanks.

A few commercial boats pay me to test their tanks at the beginning of each season, after they've cleaned them. These are pretty trivial tests, but they take a few days. I'm not going to post an ad here, but if you're really curious, send me a PM. Some public health departments will also do a free test for coliform bacteria, but not much else. At the other end of the scale, I once set up a system for an oil company to test water delivered to their offshore rigs around the world by sometimes-dubious tenders. After testing for a while, we decided that they should be set up to measure total bacteria, coliform bacteria, and salt water intrusion, on site. Samples would be mailed out once a month to measure heavy metals and arsenic. At that time, there was no simple way to test for viruses, but we used the time-honored assumption that the presence of either E. coli or Enterococcus would be a good canary in the coal mine.

For small tanks, the capful of bleach in 10 gal is a good measure, after shock chlorinating and cleaning the system. You can also get inexpensive kits to test chlorine residual (easier to do on the spot than trying to test for bacteria.) But most people probably don't need them.

Carbon filters, and any other kind of filter that you buy at Home Depot or Culligan WILL NOT remove bacteria. (Yes, I know it says that they do on the label, but it's not true.) In laboratory tests, they remove bacteria for about four hours. After that, they become a net SOURCE of bacteria, boosting numbers 1000x or more beyond unfiltered water. They're great little bioreactors where bugs love to grow.

 

[bgary]

Thanks, all, for the great info.

I think - for the moment - I'm going to keep doing what I'm doing: use tank water for washing hands, use bottled water for drinking (and cooking).

I have thought about putting a "Brita" filtering pitcher on the boat, with the thought that the filter would take out any nasties and make the tank water suitable for drinking, but... if a filter won't take out critters, it's not worth the effort.

I'll plan on flushing the tanks and adding some bleach anyway. Couldn't hurt.

BTW, that reminds me... when adding bleach, is this just normal ordinary grocery-store bleach?

 

[Christian Williams]

Just for the record, I always drank Makana's tank water, right down to the empty tanks. Never seemed anything but fine.

Good to know the reality of Culligan filters. I guess what they do best is advertising.

 

[toddster]

Don't get me wrong... a lot of people are stuck with very bad water sources. There are treatment systems that can improve that, when they are designed according to a water analysis report.
But yeah, the advertising is atrocious. Not everybody "needs" a water softener. Not everybody needs a "whole house filter." Especially if you are on a municipal service. And half of the stuff sold on the internet is pure snake oil.
People think that the pitcher-type filters make their water "taste better" because those pitchers are kept in the refrigerator. It's colder than the tap water, not purer.
There are two things that you can buy to reduce bacteria: chlorine drip systems and ultraviolet treatment. But only if they are installed and maintained properly. If you have city water, the city does that for you. If at all possible, it's better to arrange things so that you don't need treatment in the first place.

Edit: Those carbon filters can remove stuff like disinfection by-products (the downside of chlorination) small amounts of sulfide and trace organics that cause odors. But the rest of the system downstream from them will be unprotected from bacteria. If used, they should be the last thing in the system, and changed frequently.

 

[Pat O'Connell]

Hi Respected Sailors... When bottled water went down to a little over a dime a bottle it replaced drinking from our tank. Never looked back. It is a little inconvenient to have to leave the mooring and stop at the fuel and water dock to fill up as well.
Best Regards
Pat 1981 E28+ Universal 5411 Chips

 

[bgary]

I always drank Makana's tank water, right down to the empty tanks.

Did you have any sort of cleaning or flushing or treatment regimen?

I'd *really* like to be able to do this...

 

[Christian Williams]

Nope. When I drew a glass of water, it was clear and tasted fine. That was my "standard."

I didn't use the optional bow tank #3, too much weight forward when sailing light and alone.

I think water tank inspection ports are standard, easy enough to empty and clean.

 

[bgary]

Nope. When I drew a glass of water, it was clear and tasted fine. That was my "standard."

Thanks.

Yeah, I don't use the bow tank either. Old-racer mindset about keeping weight out of the ends, or something.

I've popped the inspection ports on both (port and starboard) tanks In both cases, the port is big enough to get my hand into but not big enough to reach the corners. Both have a light patina of (something) coating the bottom, letting them sit not-quite-empty for several months was dumb, but probably not irreversibly dumb.

I figure I'll run a swab-on-a stick everywhere I can reach, fill and flush (using a hose and a stand-alone pump) a few times, see how they clean up and then fill with some known-good water and give it a try.

And then, if I die of Ebola in the next couple of months, I'll have my heirs remind the forum that I drank from the tanks. ;-)

 

[sleepingsquirrel]

FDA and CDC allow us to use a 0.2 micron filter to remove bacteria in the water to perform high level disinfect of medical equipment. Probably ok to drink at this level of filtration.