drinking water from holding tanks

jssailem · Jul 27, 2016

First I suggest you read our member Peggie Hall's book on plumbing for you boat. She describes a method to sanitize the fresh water system. Additionally you could add a water filter to your system that removes 99% of the bad tastes and crawlly things that can make you sick. It's not always the water you put in the tank, but the length of time you leave it in the tank between use. Note your water heater does not get hot enough to kill the germs. You need to boil water for 5 minutes to do that.
Bottled water anyone?

njlarry · Jul 28, 2016

Holding tanks hold raw sewage. Do not drink from them.
Fresh water tanks are different. Peggys book will help.

CHARLIE STAGE · Jul 28, 2016

I am wondering if the previous owner drank the water from the tanks. If so what was his/her comments on the state of the water?
If the boat sat dry for some time then I would first check the tanks for bacteria or other settlement inside. Long storage with any amount of water inside can breed some awful taste and cause physical discomfort. I would go so far as to pull the tanks and thoroughly clean them out. I have removed my tanks twice since I bought my boat as routine maintenance. The water lines stay in place but I flush them with a chlorine solution before actual use.
I sometimes use a PUR home water filter on the faucet if I will be out for a length of time and fill from suspect water sources. I use a filtering pitcher at other times for those who have reservations about drinking the water. I have no such reservations either way.
Last of all there are a number of water treatment products on the market that can remove some of the taste and bacteria problems. Try whatever you may, I am currently using one from West Marine that has an almost similar to spring water taste, but it loses its effect after water has been in tank for two weeks or more.

Daveinet · Jul 28, 2016

njlarry said:
Holding tanks hold raw sewage. Do not drink from them.
Fresh water tanks are different. Peggys book will help.

Yes, when I read the title, I really wondered where this was going and figured the terminology better get clarified pretty soon.
When I first bought my motorhome, the fresh water tank was awful. Mixed a half gallon of chlorine, let that slosh around for a few days. Emptied it, and mixed on a 1/4 gallon of chlorine. Let that slosh, and drained it. Next tank, I used the rest of the chlorine and was at least able to use the shower. Over the next 2 or 3 tank fulls, all the smell was gone, and all the residue from who knows what, was gone. Now only occasionally I use just a couple of table spoons of chlorine less than once a year. There is water always in the tank. In the winter, the motorhome sits unused with a little water in the bottom of the tank. I have not ever had a problem with it growing things since then. That was about 15 years ago.

Peggie Hall HeadMistress · Jul 28, 2016

This subject comes up regularly. The most recent thread, which includes complete instructions for recommissioning the fresh water system is here:
http://forums.sailboatowners.com/index.php?threads/bleach-into-water-system.178928/#post-1293062

JRacer · Jul 28, 2016

One item to consider: I have a water level sending unit in my water tank that is similar to the sending unit you find in a fuel tank. It "tells" a water level gauge how much water is in the tank. I used a vinegar solution to clean out my tank after having installed the sending unit and I did not leave it in there very long. What happened was, the fumes from the vinegar solution corroded the contacts on the sending unit! So, be advised if you happen to have a water level gauge that you might not want to use a vinegar solution in the water tank..

The Garbone · Jul 28, 2016

Did ours with bleach and I will make coffee with it. We use a 5 gallon cask full of icewater for drinking, tied at the end of the galley bar, fits perfect.

CloudDiver · Jul 28, 2016

Considering different plumbing issues with boats, and even scale deposit build up with a house, I always thought it would be prudent to invest the extra money and time to add strategic by-pass valves and a place to add a temporary 120V pump. That way when dock side (shore power for the 120 V pump) one can use biocide, chlorine, de-scale solution, or what have you to do a recirculation cleaning of the fresh water system. Sound like too much or too difficult? Its probably too daunting to add these valves and extra connection points to an existing plumbing system... if only builders could consider this during new construction (boat OR homes).
Also, isn't it better to use chlorine granules rather than household bleach?

Don S/V ILLusion · Jul 28, 2016

brad minda said:
How and what should I do to make them safe.

The short answer is you don't!

You can take steps to make the water 'safer' but simple steps like chlorination don't make the water 'safe'. It serves only to make you feel better about drinking/bathing in it. There is nothing you or anyone else can do to make it 'safe' either for drinking or showering.

Hypochlorite solutions in nominal concentrations don't kill molds, algae or other common contaminants nor do they affect the presence of or eliminate other chemical contaminants. Stating otherwise is misleading.
Unlike boat systems, municipal systems using hypochlorite as a disinfectant are closely monitored and used in combination with other treatment techniques. Boats are different animals.

Don S/V ILLusion · Jul 28, 2016

CloudDiver said:
Also, isn't it better to use chlorine granules rather than household bleach?

The efficacy is the same, however, granular Cl must be stored dry. If it gets wet, an exothermic reaction can occur creating a fire. One manufacturing facility burned down some years ago because a window was left open during a rainstorm and the stored pallets got wet. Needless to say, boats don't make good dry storage.

Mypax · Jul 28, 2016

We have been drinking water out of our tanks for 22 years. It's all about how often the water in the tank is exchanged. In our case, it is usually about once a week. Occasionally we will be gone for a 2 week spell with no problems whatsoever. In general, if you use the boat a lot and regularly go thru the water, your problems go away. By the way, city water often comes out of a really big tank. Just sayin'...
--Allan

CHARLIE STAGE · Jul 28, 2016

I agree on the not using a chemical/chlorine alone idea, it was basic science when I went to school.
A Municipal water system (at least ours) filters the water from the river and then chemically treats it before it even goes into the stand tank and becomes a useful drinking liquid. Then it is used quite quickly so there is very little stand time. That is why I use a filter on my boat for extended trips and for fill ups from other sources.
As to the other answer of: storing water in a tank while the boat/motor home is on the hard for winter. I suspect you have treated your tank with anti-freeze prior to storing and I am sure you flush it before use. Therefore you have eliminated the stale/bacteria tank problem with stored water.
I have never had a water problem, just people that did not choose to drink it. C'est la vie.

Don S/V ILLusion said:
The short answer is you don't!

You can take steps to make the water 'safer' but simple steps like chlorination don't make the water 'safe'. It serves only to make you feel better about drinking/bathing in it. There is nothing you or anyone else can do to make it 'safe' either for drinking or showering.

Hypochlorite solutions in nominal concentrations don't kill molds, algae or other common contaminants nor do they affect the presence of or eliminate other chemical contaminants. Stating otherwise is misleading.
Unlike boat systems, municipal systems using hypochlorite as a disinfectant are closely monitored and used in combination with other treatment techniques. Boats are different animals.

Peggie Hall HeadMistress · Jul 28, 2016

CHARLIE STAGE said:
As to the other answer of: storing water in a tank while the boat/motor home is on the hard for winter. I suspect you have treated your tank with anti-freeze prior to storing and I am sure you flush it before use.

Recommissioning the system each spring according to the directions in the link I posted above removes ALL the antifreeze taste smell in addition to cleaning out the molds, fungi etc that live in the plumbing and leaves you with water from the tank that tastes and smells as good as any from a faucet on land. If that's not good enough to suit you, install a faucet filter on the galley sink. PUR makes a pretty good one for a very reasonable price.

CHARLIE STAGE · Jul 28, 2016

Peggie Hall HeadMistress said:
Recommissioning the system each spring according to the directions in the link I posted above removes ALL the antifreeze taste smell in addition to cleaning out the molds, fungi etc that live in the plumbing and leaves you with water from the tank that tastes and smells as good as any from a faucet on land. If that's not good enough to suit you, install a faucet filter on the galley sink. PUR makes a pretty good one for a very reasonable price.

Sorry Peggy the response was misdirected. Read Daveinet's full response, I was just responding to his ...leaving water in a tank over winter with no problems... I believe my answer qualified all of the statement/s he wrote that I was concerned about. I have never had a problem in 37 years of owning boats with holding tanks.

Daveinet · Jul 28, 2016

The tank gets emptied, but still had about an inch of water in the bottom. I only blow out the lines with air, no anti-freeze. So that water is still OK and doesn't seem to grow anything. The only caveat I would have is that I am using well water from my house, which I can only figure has no growth in it, because the water does not seem to go bad. Once you kill everything off, unless you introduce some sort of critters to it, there is no source to initiate growth. I suspect those who have problems are using questionable water. (not that questionable water is easy to avoid)

Peggie Hall HeadMistress · Jul 28, 2016

We have two discussions about the same subject going on in two different forums--Catalina 30 and Ask a Hunter Owner...and it's creating confusion, at least for me! So I'm gonna ask Phil to move both of 'em to the Plumbing and sanitation forum where they belong.

Rick D · Jul 28, 2016

I always wondered about people who refuse to use the water from tanks. We put municipal water in the tanks, turn them over regularly and have done so for 40+ years (in SoCal with mild weather and 12 month use). Yet I have people come aboard and wrinkle their nose when the see us using tap water to drink. When we go to Mexico, we use purified water to fill then tanks. We get the same reaction when people come to our mountain home and we use tap water. It's the same stuff they bottle and sell! Friends who are on municipal water boards do the same at home and in their RV's. So, Don; given your EPA background, what do you do? What's the problem? Boats in high-heat areas, or those which are hauled in the winter, or what?

Tally Ho · Jul 28, 2016

I don't use enough water to keep it really fresh, and after a while, it gets a little "skunky".

Lately, I have added a splash (few ounces) to each 30 gallon tank when I fill them. This seems to keep the tank from getting skunky between fills.

I don't drink the water, but use it for washing, cooking, etc.

Greg

Ron20324 · Jul 28, 2016

[QUOTE="...I don't use enough water to keep it really fresh, and after a while, it gets a little "skunky". [/QUOTE]

At the very least, I sail every other weekend with my club. In between, at the slip, I run the water to get all- or most- of the water out of the tank. Next weekend, fill the 40-galloin tank with fresh. Last weekend we were in a hurry. I filled the tank, then filled my waterbottle from the tap. I took a sip, and my face told the crew "don't drink it". I had overlooked running the tap whi;le the tank was fiklling, and in effect sipped water that had been in the plumbing for 2 weeks. I waited for the fresh water to come out the faucet and enjoyed the water.