Cleaning the Fresh Water System

[off-the-grid]

I put a little bit of bleach in my tanks a few months back when I pulled them. Only used about a cap full or so in each 30 gallon tank, since I read somewhere only to use a few teaspoons.

Anyway they're getting pretty funky again, maybe even worse than last time. Even the Brita water doesn't taste great.

How often do you generally need to clean the water system?
Should I use a lot more bleach this time, maybe let it sit, then pump both tanks dry?
My tanks are currently pretty full. Would pouring the bleach in on top be sufficient?
Or do you really need to pour the bleach into empty tanks, and then fill them?

[Astrid]

You should probably 'shock' your fresh water system. This involves using more chlorine than you have been--about one cup per ten gallons. You will need to keep the system under pressure so that all water lines and fixtures have the chlorine treated water.

Let stand about 8 hours or overnight, but no longer than 24 hours, then open all faucets and fresh water fixtures to drain the system. I would remove the faucet screens and disconnect any filters first, as one is likely to have a fair amount of debris come out that has collected over the years. Shocking the system should be an annual or bi-annual chore.

After the initial draining, refill your system with fresh water, pressure up, and reflush all your water lines, faucets, and wash down fixtures. Keep this up until smell, clarity, and taste of the water are to your liking.

It is worth noting that simply cleaning out the tank is not enough, as critters will be happy in little used water lines, so run all your lines once in a while to keep water in them from becoming stagnant--likewise, run the dock hose for a few minutes to get stagnant water out of the filler hose, before starting to fill up.

[peghall]

Although most people think only in terms of the tank, the plumbing is actually the source of most foul water, because the molds, mildew, fungi and bacteria which cause it thrive in damp dark places, not under water. Many people—and even some boat manufacturers—believe that keeping the tanks empty reduce the problem, but an empty water tank only provides another damp dark home for those “critters.”

There are all kinds of products sold that claim to keep onboard water fresh, but all that’s really necessary is an annual or in especially warm climates, semi-annual recommissioning of the entire system—tank and plumbing. The following recommendations conform to section 10.8 in the A-1 192 code covering electrical, plumbing, and heating of recreational vehicles (which includes boats). The solution is approved and recommended by competent health officials. It may be used in a new system a used one that has not been used for a period of time, or one that may have been contaminated.

Before beginning, turn off hot water heater at the breaker; do not turn it on again until the entire recommissioning is complete.

Icemakers should be left running to allow cleaning out of the water feed line; however the first two buckets of ice—the bucket generated during recommissioning and the first bucketful afterward--should be discarded.

1. Prepare a chlorine solution using one gallon of water and 1/4 cup (2 oz) Clorox or Purex household bleach (5% sodium Hypochlorite solution ). With tank empty, pour chlorine solution into tank. Use one gallon of solution for each 5 gallons of tank capacity. (Simpler way to calculate: 1 quart bleach/50 gal water tank capacity)

2. Complete filling of tank with fresh water. Open each faucet and drain cock until air has been released and the entire system is filled. Do not turn off the pump; it must remain on to keep the system pressurized and the solution in the lines

3. Allow to stand for at least three hours, but no longer than 24 hours.

4 Drain through every faucet on the boat (and if you haven't done this in a while, it's a good idea to remove any diffusion screens from the faucets, because what's likely to come out will clog them). Fill the tank again with fresh water only, drain again through every faucet on the boat.

5. To remove excess chlorine taste or odor which might remain, prepare a solution of one quart white vinegar to five gallons water and allow this solution to agitate in tank for several days by vehicle motion.

6. Drain tank again through every faucet, and flush the lines again by fill the tank 1/4-1/2 full and again flushing with potable water.

An annual or semi-annual recommissioning according to the above directions is all that should be necessary to keep your water tasting and smelling as good as anything that comes out of any faucet on land. If you need to improve on that, install a water filter. Just remember that a filter is not a substitute for cleaning out the system, and that filters require regular inspection and cleaning or replacement.
To keep the water system cleaner longer, use your fresh water...keep water flowing through system. The molds, fungi, and bacteria only start to grow in hoses that aren't being used. Before filling the tank each time, always let the dock water run for at least 15 minutes first...the same critters that like the lines on your boat LOVE the dock supply line and your hose that sit in the warm sun, and you certainly don't want to transfer water that's been sitting in the dock supply line to your boat's system. So let the water run long enough to flush out all the water that's been standing in them so that what goes into your boat is coming straight from the water main.

Finally, while the molds, fungi and bacteria in onboard water systems here in the US may not be pleasant, we're dealing only with aesthetics...water purity isn't an issue here--or in most developed nations...the water supply has already been purified (unless you're using well-water). However, when cruising out of the country, it's a good idea to know what you're putting in your tanks...and if you're in any doubt, boil all water that's to be drunk or used to wash dishes, and/or treat each tankful to purify. It's even more important in these areas to let the water run before putting it in the tank, because any harmful bacteria will REALLY proliferate in water hoses left sitting on the dock.

[ehh]

What would you think about using Nolvasan instead of bleach? I am concerned about corrosion. I don't have any way of draining my tanks except into the bilge and pumping them out from there.

[Astrid]

You would normally drain your tanks after bleach shocking the system by opening all your faucets and wash down fittings and keeping your pressure tank pressurized (if you have one) or by keeping your pressure pump going. Once the tank is more or less empty, refill at least in part and empty again by the same method. Any residual bleach left over will be thoroughly diluted with the next refill. Since you are only doing this once a year or so, I would not worry too much about corrosion.

Remember, cleaning the tanks themselves are only secondary. What you should be most concerned about is cleaning out the water lines from the tanks to the faucets and other fittings.

As far as using Nolvasan goes, it is much more expensive than bleach. It is a topical veterinary surgical scrub and disinfectant with the active ingredient chlorohexidine. Nolvasan costs about $60.00/gal and is chlorohexidine diacetate while generic chlorohexidine gluconate is around $22.00/gallon and is much safer to use. Nolvasan is extremely strong and is registered with the EPA in the United States.

In my humble opinion, bleach will do just as well at far less cost and with far less post treatment rinsing.

[clifford sloan]

When living aboard and chartering our water tanks got used enough to not have to worry about "standing water problem" but just to be sure we add a fifth of gin to each tank when they got down low enough to hear the slosh. Maybe that's why we had such happy guests? Seriously gin workks!
All the best,
Clif

[smurphny]

I put a cap of bleach in the tank every couple of fill-ups. Would rather have a little chlorine taste than microorganisms growing in the tank. For drinking I also carry two 5 gal. totes which I try to keep fresh water in. Iodine is also said to work as a disinfectant, although I have never tried it. Have never heard of anyone using H2O2 but it seems that this might also work.

[off-the-grid]

Peggy, I've always known that you need to run the hose for a while, before using the water that comes out of it, but is it really necessary to run it for THAT long?

I'm in Miami right now, and that could really be a problem. The faucet by the marine patrol dock has a button that you have to hold down to keep the water flowing.

smurphny - Iodine water has it's own great taste.

[peghall]

Originally Posted by ehh

...I don't have any way of draining my tanks except into the bilge and pumping them out from there.

You don't have any faucets??? That must make washing dishes and brushing your teeth VERY challenging!

Ok...I've had my fun. Apparently the directions don't make it clear that you're supposed to drain the tank "through every faucet on the boat" EVERY step.

Grunster...how long you let the water run depends on how long it takes for the temperature of the water coming out to drop significantly, indicating that it's now coming from the main, no longer water that's been sitting in the dock supply line. That could be 3 minutes...it could be 20. Whether you want to transfer critters that have been growing in the dock supply line into your fresh water system is your call.

[ehh]

Actually there is a faucet, just no sink. It was replaced by a fridge.

[CarlF]

While Peggy probably has better information, my understanding is that chlorine is only effective for about 24 hours in a tank (e.g. once exposed to air). If it's killed everything by then, great. But it won't treat water added later or anything that survived the treatment that then starts to grow.

Even in it's plastic jug, chlorine needs to be fresh to be full strength. It's reportedly fine at six months but by 12 months it's really not much good.

Carl

[Music]

To add to Peggy's post. Purge Baby Purge. I have seen many municipal water systems that are questionable at best. I would suggest a particulate filter attached to a charcoal filter, If your water supply is unsure. At least a particulate filter. Particle filter for sand rocks and clams... The Charcoal filter will help with taste and remove some bad chemicals.
Sounds extreme but not too difficult, if you maintain your system on a schedule.

[Hud3]

If you shock your system like Peggy and Astrid suggest, it should be OK for quite a while if you're cruising regularly and using the water. We did that on re-commissioning and when cruising re-supplied every 10 to 12 days and never had grunge issues--this was in the Tropics.

If you don't use the boat all that much, you'll probably need to treat it in the interim. When we lived on the Chesapeake and mostly day-sailed between weekend or week cruises, I'd put some 27% hydrogen peroxide in the tank every couple of weeks to keep it fresh. Our tank was aluminum, so I didn't put chlorine in it. If your tank's not aluminum, chlorine is OK.

[Hugh Walker]

Thanks for the great advice, I'm just about to clean my tanks and I'm wondering why you wouldn't let the treated water sit in the hot water tank? My natural thought is to treat the tanks then run the hot water for 30 mins to bring the treated water in the hot water heater tank then allow everything to sit. Does the chlorine damage the hot water heater?

[peghall]

Chlorine CAN damage the heating element and thermostat...but won't hurt the tank itself...so you won't damage anything if you don't turn the water heater at the breaker till ALL the bleach is out of it. But the problem is, once you get the chlorine solution into the hot water tank, it takes forever--a gazillion flushes--to get it all OUT. That's why most people who use antifreeze to winterize the fresh water system bypass the water heater.

So it's your choice...if you want to put the solution into the water heater, just know that you can only use the heat exchanger to heat water till it's ALL flushed out...and be prepared to accept hot water that tastes/smells like swimming pool or laundry for a while.