Fresh Water Testing

[Rob McClain]

Our 34' sailboat has a 75 gallon fresh water tank. We don't generally use the water for drinking, although a sip here or there does occur. Instead, we'll use it for doing dishes, brushing teeth, and little things like that. Last weekend while on the boat my wife developed an unusually bad case of diarrhea and associated conditions. While I had no problems, we're concerned that our water tank might have developed a bacteria, although we've experienced no indication of any problems until now. I've read Peggy's directions for recommissioning a water tank, and I'm inclined to do this since I never have, but before doing so I would still like to know more about the actual condition of our current supply of tank water. I've looked for companies where I can get a water sample tested, but not really found any that seem to fit this need. Has anyone ever done this before - and if so any recommendations? Same questions regarding those do-it-yourself test kits that supposedly allow you to test water for bacteria and other things.

While I know doing the recommissioning is still a very good idea, I've noticed this requires filling and emptying of the water tank several times before the process is completed. Since we're on water rationing in Northern California due to a dought, I'm a bit hesitant to waste around 300 gallons of water right now. Then again, I would like to know if my water is generally usable without having to boil it.

I have no expertise in this field, nor am I scientificly inclined, so I welcome any thoughts or suggestions...

 

[Bob S]

I'm not an expert but i did add a cap full of Clorox bleach when I filled our tanks. I know my town chlorinates our tap water. We don't drink our boat water either. Showers tooth brushing and dishes.

 

[Don S/V ILLusion]

Rob
There is no way short of expensive analyses to ensure the tank water is potable and even if you chlorinate and flush the system as some suggest, although less likely, you can still ingest numerous bacteria immune to chlorination such as cryptosporidium which can cause the specific symptoms you describe.

Home test kits are typically useless as they cannot identify the presence of most bacteria or virusus. Also, most filters using carbon and/or a filter media over 1 micron are also useless but can eliminate taste (ironic, isn't it?)

My suggestion is do not use the tank water for brushing teeth or anything similar, regardless of whether you chlorinate. None of us possess the ability to ensure a residual chlorine level to determine efficacy which makes chlorination a crap shoot to my mind.

Also, consider that the carbon filters, whether in combination with a porous media or not, are only effective at removing taste and some sediment which begs the question whether they provide anything other than a false sense of security.

 

[Steve Dion]

We have been using our fresh water tank for years without any treatment. Of course that has absolutely "nothing" to do with your situation.

We do drink our water but it is typically used in cooking. I have a filter that I purchased at Camping World. It has a mount that hooks on the dock box and I fill the tank with all filtered water.

There are filters that can remove spores and other critters from the tank, but I suggest you bite the bullet and refresh your tank as Peggy recommends. Your health is worth a lot more than 300 gallons of water.

 

[jackhartjr]

Rob, the way to do it is to fill it once with the chlorine mixed in, open each faucette until you smell the chlorine coming out, let that set for a day, dump it, fill once more with fresh, let it set a day, dump it, then you are ready to go. Only used 150 gallons that way.
We do that on our RV and have never had a problem.
And in the future...use the tank!lol
Jack

 

[Ross]

Take a sample to your local health department for testing. Tell them it comes from a spring on your land and want to know if it is safe for drinking.

 

[Guest]

Water Testing

FWIW, we have two tanks that total 150 gallons of potable water. I normally alternate tanks so as to keep the water as fresh as possible. I used Peggie Hall's commissioning procedure when we first purchased our boat in 2002 and not once since. Our water tastes as fresh and sweet as city tap water. I do, however, use a PUR brand faucet filter for all drinking water.

You can pay about $50 for basic water quality testing, which I have never done. I would suspect your local county office can help you out as well. Our water comes from the Sultan water shed, one of the best, IMHO.

Terry Cox

 

[RichH]

Rob -

Such boat tanks are essentially 'stagnant' systems that 'can' quickly develop an unbelievably thick 'bacteria slime' (calcyx) on the walls in very short time. Once such a thick biofilm develops the ONLY way to remove it is to mechanically scrub it, then follow up with repeated multiple sanitizations (chlorine, etc.). If you have a large biofilm already developed, simple 'sanitizations' will not work ... as sanitization will only kill/stun the upper layers of the biofilm leaving the deeper/lower layers intact and alive; and further, the dissolving dead bacteria will release their cell debris into the water .... and you get the 'trots', fever ...... or worse. You really have to open the tank, and feel for the (slimey) calcyx/bio-film, etc.

Many common and quite pathogenic bacteria can be found in 'stagnant' potable tank water. The remedy is 'tank hygiene' - soap, water, scrub brush; then, followed by several 'sanitizations' with chlorine, etc.
Beware- What you find offered mostly on the 'internet' for (boat) tank sanitization is for commissioning clean/new tankage for potable water; not fouled tanks with a developed biofilm. Such internet postings of sanitization recommendations are based on National Sanitation Foundation (NSF) recommendations for 'active' (flowing) NEWLY installed (clean) systems .... NOT one that is fouled/contaminated. To make the assumption that the standards that apply to 'active' water systems equates to 'stagnant' ('dead end') systems is totally BAD advice and informantion. To simply saniitize a fouled system without removal of the biofilm leaves the potential of 'sickeness' due to the remaining/unremoved cell debris that will eventually dissolve. This cellular debris (polylipposaccharides - pyrogens) are what causes fever, etc.

Lab testing the water will be of no value as if the tank is un-hygienic and bio-fouled, there will be too many species and the 'counts' will be "too numerous to count" as an official documented answer ... costly and you will still need to scrub the tank, etc.

Soap/detergent and scrub brush is the 'usual' answer, then sanitize once the system is 'clean'.

Once you return a tank to good hygiene, then you can maintain it that way for a long time by simple periodic addition of chlorine (@ ~1 part per million) ... or so that the effluent water has 'just the barest hint of chlorine' to your WIFES nose.

OK youre having a drought and dont want to 'waste' water. How much water per person will go down the toilet during an episode of the 'trots' ?????

hope this helps.

 

[Allan12210]

Sterilization Required

Rob,

If you have a bacterial contamination in your water, you need to sterilize the entire system including the tank(s) hot and cold lines, fill pipes, vents and faucets. Basically you need to sterilze all interior surfaces that the water could come into contact with as it may be coated with a biofilm which is much more populated than floating bacteria. Just rinsing can leave bacteria that will just recontaminate the water when refilled.

With that being said, it is not that terrible to do. We had to do flushes of our clean water systems where I used to work every six months. I applied the same techniques on my boat.

The easiest chemical to obtain is Clorox bleach (the original kind, not the new ones with out chlorine or with other ingredients). You don't want it to be too strong as it will damage o-rings and rubber pump diaphrams if left too long. I would drain down the fresh water tank to about 10 gallons. Add 1 cup of Clorox per the 10 gallons to the fresh water tank. Go to the hardware store (do you know where Pagano's is in Alameda?) and buy an aerator replacement for your galley and head faucets that adapts to a garden hose thread. Screw that into the faucet and then attach a hose. Run the hose from the faucet back into the deck fill. Turn on both hot and cold taps full blast and recirculate the water. Make sure you are rinsing the fill pipe very well as it circulates. This needs to run for 10 to 15 minutes so all the lines are exposed to the chlorine and water is moving at a high velocity. This will aid in breaking loose any bacteria colonies. Switch the garden hose to the head sink and continue recirculating back into the deck fill for another 15 minutes. Then take the garden hose end and stick it against the tank vent and circulate the water through there for a while. This should also wet the interior surface of the fresh water tank. Turn everything off and let it sit for about 2 hours. Drain by turning on the shower to pass the water out that way running both hot and cold full blast. Stick the shower head out the hatch or porthole. Change/clean the filter screen on your fresh water pump. You can refill with about 10 gallons of clean water and recirculate again briefly through each tap then drain via the shower. That should sterilize the system. After filling the fresh water tank back up run some out each faucet down the drain.You don't want to have to do this too often as it can be hard on the o-rings, but if you have a contaminated water system, it needs to be done for obvious gastro-intestinal reasons. See Peggy's book for additional details. I like the recirculation approach as it works well at exposing all surfaces to the sterilizing solution at high velocity and doesn't require as much water.

If you have a source of 27% hydrogen peroxide (dangerous) you can dilute to 5% and do the same procedure. You would want to wear gloves and safety goggles. Hydrogen peroxide doesn't damage the seals and will eventually break down to water and oxygen. The stuff you buy for treating cuts is less than 1/2% so it won't work.

Good luck.

Allan

 

[sailingdog]

The best directions for shock treating a fresh water system are probably those by SBO's maven Peggie Hall. Available from Beth Leonard's website as a PDF.

 

[kloudie1]

Allan, interesting that you mention hydrogen peroxide. That is available in about 30% strength at pool stores that handle Baquasil .. It is used as an antibacteria "shock" treatment and is food grade.. It makes a fine sanitizer since, as you mention, degrades to water. Dangerous stuff that has to be handled carefully!

 

[RichH]

Listed are several sanitization schedules used in 'industry' for adequate shocking of a typical / quality water system.

Once you gain 'hygiene', one of the best ways to long-term prevent reinfection is to apply a 'filter' on the tanks vent line to prevent aspiration of bacteria/fungus into the tank. Without a vent filter, every time you draw down water from the tank spores and microorganisms will enter ... through the vent. You can buy from various (quality) filter distributors a 'capsule' filter which contains a hydrophobic 0,2µM (100%) absolute filter membrane. Alternatively you can simply take a fist sized 'wad' of bandage cotton covered with bandage gauze and simply tape this over the vent; keep dry and replace yearly. A vent filter will greatly increase the time interval for tank scrubbing/brushing/sanitization.

High concentration (30%) Hydrogen Peroxide is a VERY dangerous chemical and if you dont know or have the chemical expertise to handle it properly you can become seriously injured. A minimum of 10% H202 is required for sanitization purposes - VERY expensive in comparison to simple Chlorox. Chlorine for shock sanitization typically is in the concentration range of 15 parts per million - for CLEAN tanks.
In industry, chlorine is being rapidly replaced by mixtures of peracetic acid and H202 - mixtures prepared commercially and available as "Minncare" (MarCor Industries, Minn. MN) exponentially more effective than Chlorine, etc.

If all this is mindboggling and you live near an area where the dairy industry is found, plus your tank does not have any access ports for mechanical scrubbing of the internal, simply hire a dairyman to caustic soak (dissolves the bacteria) the internals and then repeatedly shock sanitize.

The simple solution remains - detergent and a scrubbing brush

 

[Don S/V ILLusion]

Peroxide has a number of advantages over Chlorine solution and is readily available at most pool supply stores in concentrations which are an effective alternative to chlorine. They are safe evidenced by the huge numbers of pool owners using it without incident as long as you follow common sense precautions. The common peroxide found in pharmacy stores is not concentrated enough to be effective.

The other big advantage peroxide has it that it is almost idiot-proof in that mixing rates are much less critical. With chlorine, the only real way to determine efficacy is to determine residual concentration and, although someone recommended the "sniff" test, that isn't very precise. By comparison, peroxide is less sensitive to "cap full" measurement.

In terms of which is more hazardous, chlorine is far worse by any measure, can destroy seals and some gaskets, adversely react with aluminum tank walls and obviously bleach clothing and is an inhalation hazard.

Neither is a very practical way to ensure the safe ingestion of boat tank water which is why it's always better to not.

 

[Rob McClain]

You guys are great! I need to review these in more detail and then make a plan. I greatly appreciate all of your thoughts...

 

[Bill Roosa]

get it clean with

elbow grease and concentrated Clorox. then only put in clean water and add 1/4 cup clorox / 30 gal. If you smell chlorine then you have excess chlorination and you can reduce the dosage.
I personally make all my coffee and cook, shower, brush teeth......everything from my tank. I've done this since 2002 as a weekend sailor and did it daily all last summer and fall and never had any health problems.

 

[Scott]

Last year we decided to install access ports on the cover of the tank to clean it. After 20 years I envisioned algea, scum and a couple of critters. Surprisingly, it was quite clean. Only some black residue near the top 2 inches or so of the sides. Probably a maganese sulfate, as the well water at our marina has a high concentrations of sulphur, decent laxative but won't hurt you. At any rate, installation of the ports was easy and we feel much better about our water supply. We never used "house" water for drinking and still don't. During that 20 year period we treated the tank annually with chlorox, and added a few drops each time the tank was filled.

The reason for two access ports is that the tank has a baffle installed diagonally.

 

[Andy1237]

After reading all this I am SURE I will get some horrid bacteria in my digestive system and DIE! I hope I am on the darn boat when it happens! Rob-next time make sure all the SOAP gets rinsed off with hot water! I hope your wife just injested some soap with her rum and coke and all is well now!
We too use boat water for cleaning. Drinking water and coffee are made with drinking water brought on board (usually from home frozen in large jugs to assist food cooling. Keep a small bottle in the head for brushing teeth.
NOW, for the final rinse-boil a pot of water to rinse silverware and glasses! Bon apetite!

 

[Chuckbear]

we lived aboard our last sailboat for 17 years and now our new to us trawler for only for about seven months. The trawler is 28 years old. We shower, wash dishes, drink the water, make ice and do everything that folks do in houses. We have filled our tanks all over the US coast line and in third world countries in the Caribbean. We have never been sick from anything that came out of our water tanks. We do treat the tanks every couple of years with bleach but thats about it. We know and have met hundreds of live-aboards and cruisers that drink and wash from their tanks every day with no ill affects. I don't think this is as big of an issue as some might make it out to be. Chuck