Maintaining Drinking Water Tanks

[Amwasp]

Hi Anyone,
I just jumped from a weekend boat to a large boat. The boat hold 200 gallons of water in 2 tanks. Is there a testing kit I should get to maintain the waters goodness? What do most people with large storage do to maintain the water tanks?
Thanks

[projectfiji]

On top of that, how do we know what water is good for drinking purposes, and what isn't? I would assume if the old saying in Mexico is "don't drink the water" that this applies to other parts of the world.

Some sort of inline water filter? Tablet that gets dropped into the tanks?

[Hud3]

I used to haul gallon jugs of spring water to drink, and only use the water from the tanks to shower or wash dishes. Then I installed a SeaGull IV filter. It filters out bacteria, cysts and viruses. EPA approved. No more lugging jugs for drinking water. Best thing we ever did on the boat. It's not cheap, but the convenience is indisputable. We didn't have a water maker, and bought our water when cruising. The SeaGull filter removed any worry about the water source.

Check it out at www.generalecology.com. (disclaimer-no interest in the company, just a happy customer).

BTW, a little 27% hydrogen peroxide in the water tanks every now and then keeps ugly-stuff growth in check.

[sandy daugherty]

I fill my water tanks from a well during the sailing season. The water is tested annually and is safe to drink but has a slight metallic taste and a sulphor smell. I use an inline charcoal filter at the end of the fill hose, and add the recommended amounts of Aqua Bon. I need to run the tanks dry and refill every three weeks in the summer, but we drink the water, cook and wash with it, and its OK, even for coffee.

After winter storage (I drain the tank, then put just enough pink stuff in to purge all the lines) I add a cup of bleach to the first flush, then flush the system three more times to get rid of the pink taste. I have a plastic tank and the usual hoses and taps.

[Firehoser75]

You need to check out the condition of your deck fill (covers) and hoses. First off are the fills clearly labelled? You really want to avoid putting diesel in your water tanks!! Are the cover gaskets in good shape? If not, contaminates can get into your tanks. Suspect hoses should be replaced (throughout the entire system).
At the start of each season (I do this twice a year) sanitize your system as follows:
1) Drain all water from the system flowing through all taps on board. Hot water tank is off. Remove any water filters, strainers, etc.
2) Add diluted household bleach to the tank at the rate of 1 Oz. of bleach for each gallon of water.
3) Fill all water tanks with this solution. I have "plastic" tanks so I add the bleach to the empty tank and immediately fill with water.
4) Now run water from all taps until you can smell bleach at each location.
Leave the system pressurized with this solution in it for 4 to 12 hours.
5) Drain the system and refill with fresh water.
6) Drain the system again and refill with fresh water. Re-install any strainers, filters, etc.

I use a charcoal filter on the hose for filling my water system and have a tap mounted filter we use to filter water for coffee or tea.
This has worked very well, but we have not gone to places where we would worry about getting "tourista" from the water. Hud's idea may help with that.
Hope this helps,
Tom

[forsailbyowner]

Our answer is use them. most tap water , excepting well water is chlorinated and if it recirculates will keep tank fresh. Once in a great while we shock them when we get a slip, but thats like spring cleaning stuff.

[Pblais]

Charcoal filters while effective for taste will not remove parasites or cysts. You need a fine filter to get those and chlorine alone will not kill them. Boiling for one minute will kill them always. Chlorine works well if the water was safe to begin with (free of parasites) but parasites and cysts are unaffected by it. Bacteria seems to be handled well with chlorine though I doubt that threat is the one you need to watch for. Parasites are the ones that can linger on for years.
If you are using chlorinated water it will stay fresh quite a long time assuming no light can enter the tank. Algae are photosynthetic and can not propagate in darkness. Mold and parasites can.

You really can't filter water going into the tank to any serious level other than to remove some of the chunky stuff. Filters at the tap like the Seagull do a better job. Well water can not be assumed to be safer.

[Stillraining]

FWIW

A solid carbon block filter with no bypass WILL remove 99.99 of all patogens

[Pblais]

A solid carbon block filter with no bypass WILL remove 99.99 of all patogens

Given they are only 10 microns and you need a filter of 0.2 microns it isn't that great. But what the heck if you can't see it it must be OK.

[Ziggy]

Originally Posted by Firehoser75

You need to check out the condition of your deck fill (covers) and hoses. First off are the fills clearly labelled? You really want to avoid putting diesel in your water tanks!! Are the cover gaskets in good shape? If not, contaminates can get into your tanks. Suspect hoses should be replaced (throughout the entire system).
At the start of each season (I do this twice a year) sanitize your system as follows:
1) Drain all water from the system flowing through all taps on board. Hot water tank is off. Remove any water filters, strainers, etc.
2) Add diluted household bleach to the tank at the rate of 1 Oz. of bleach for each gallon of water.
3) Fill all water tanks with this solution. I have "plastic" tanks so I add the bleach to the empty tank and immediately fill with water.
4) Now run water from all taps until you can smell bleach at each location.
Leave the system pressurized with this solution in it for 4 to 12 hours.
5) Drain the system and refill with fresh water.
6) Drain the system again and refill with fresh water. Re-install any strainers, filters, etc.

In addition to Tom's suggestions, if the water is suspect, you can use AQUATABS RV/Marine Kit (available from Emergency Water Purification, Water Purification Tablets | Global Hydration). The kit contains NaDCC water treatment tablets (1 tablet/20 liters) and test strips to measure free chlorine level. You can't order them on-line--you have to call their number. The charcoal filter will remove any taste and odor of chlorine.

[nautical62]

If you choose to use chemical purification, you need to be aware of what your tank and other water delivery system parts are made of. Chlorine does not go well with stainless. I believe iodine is a better choice for that.

[Ziggy]

Long term use of iodine for water purification may have some health risks, and some people are allergic to iodine. I don't think 316 stainless would be harmed by free chlorine in concentrations released by NaDCC tablets in doses typically used for water purification. Maybe more of a concern with 304 stainless.

[thinwater]

After the treatment is complete (detailed by other posters) there is the matter of taste. Since chlorine is an oxidant and vitamin C is a reducing agent (anti-oxidant) a very small amount will easily kill the annoying after taste.

However, the residual protection of the chemical purifier is gone too, so this is a method best used just prior to use and not in the tank.

[thinwater]

For reasons other posters have given (health, dosage, taste) most public water supplies have gone to chloramine. This can be made with ammonia and bleach, BUT DO NOT MIX THEM TOGETHER. THEY WILL REACT QUICKLY AND THE GAS RELEASED IS POISONOUS. They are put in the tank separately at about 1/3 the dose that would be used for bleach (equal parts). The chlorine should be added while the tanks is filling (mixing) and allowed to react for at least a few minutes before the amonia is added. There is less taste, the treatment is more effective, and it lasts longer.

But please read the below links so that you are well informed by several authorities:

Information about Chloramine in Drinking Water | Stage 2 Basic Information | Microbials and Disinfection Byproducts (MDBP) | Safewater | Water | US EPA
Chloramine water disinfection creates toxic compound. — Environmental Health News

[Amwasp]

Hi everyone,

Thanks for all the information and good advice.

My plan is to invest in the water purifyer. My stomach has enough difficulty without the nasty critters nature conjures up. Because I don't know where the water in the tanks came from or how the previous owner managed the supply sytem, I'll flush and clean it with some clorine before installing the filters.

I very much appreciate all your experience. Cruisers never fail to respond to a reasonable question. Thank you all!!

John