How to keep fresh water clean

Hi Everyone,

I know this may seem like a stupid question... however I am new to this

I have a 750L fresh water tank on board the boat. I will never use this for drinking water - just for showers, washing up, washing hands, etc etc.

So my question is - how do I keep the water "clean" and free from bacteria? Do I need to even bother? Do I put chlorine in there at all?

Interested to hear what you guys all do!

Cheers,

L

Welcome aboard. Look for Peggie Halls book on boat odors. It is available on Amazon.

Usually one time Chlorox cleaning of entire FW system is all thats needed.

If you use "city" water the tank should be drinkable although it may not taste great.

First thing cruising is to taste the water after docking , to decide if you want it in your tank.

In the land based RV world the general rule of thumb is to sanitize the system with a little bleach in the water tank, turning on all the fixtures till the bleach solution flows through everything then let it sit for a time to sanitize everything....then drain and flush. Done perhaps once per season.
I've done this for several years and have never had problems....& I'll even drink the water although my primary drinking source isn't the tank.

There was an earlier thread on this so search around. I’m on limited 3G so really can’t search. The Head Mistress has some good advice on this topic. I used 4 gallons of bleach to 350 gallons of tankage for 4 hours. That’s on the strong side. You need to run it through all the taps but not the hot water tank. Remove the diffusers from the faucets. Then of course you need to fully drain the tanks and fill and run that water out. It takes me the better part of a day to complete the task.

If you do this once a year and have carbon filters on the system, you will find the water is as good or better than bottled.

But search for that thread. Lots of info.

Jim

To each their own, but I can't imagine having a boat water tank and then not being able to drink out of it.

So first for me would be to decide if the tank is suitable for making clean (i.e. is it old deteriorating fiberglass or etc.).

Then, as others have mentioned, clean out the tank. Even better if you can actually get in there and scrub the walls via something like a deck plate (bleach will kill the biofilm as I understand it, but doesn't actually physically remove it).

Next step for me would be to replace any hoses that can be replaced (perhaps with something like Pex as I think that tends to get less "ucky" than soft hose; but at least new hose).

My knowledge of filters and the like is basically non-existent since we didn't have anything like that when I was regularly maintaining a water tank. We put a specific amount of bleach (drops) in with each tank fill, but be aware that that wears off after a certain period of time (we consumed the water sooner than that would happen).

IIRC, you have to be a little bit careful with certain filters (charcoal?) as they will strip chlorine which leaves the water more prone to spoilage (?). Please don't accept this part without researching as it's just something I remember reading from a boat water expert.

Lastly, a prime source for bacteria coming into the tank is the vent. Every time you pull water out of the tank, air comes into the tank via the vent. Is that vent in a moldy anchor locker? Outside sucking in exhaust from your neighbor's generator? Most every boat or RV I've ever bought that vent hose is BLACK with mold and grossness. Ewww. Direct line into the tank.

I read a while back on the old CSBB cruising board (another water expert's post) to be aware of where your vent is and think about it as an "intake" of biological stuff into your tank. So consider where it is located. He advised a specific filter you could put on it, or he mentioned if you can put it in the boat you can wrap gauze around it with a rubber band to secure and then change it periodically.

Lastly, I wouldn't expect to be able to keep water in a boat tank for a long period of time and "keep it fresh." I'd either be using it, or would expect to exchange for clean "new" water.

JDCAVE said:

I used 4 gallons of bleach to 350 gallons of tankage for 4 hours. That’s on the strong side. You need to run it through all the taps but not the hot water tank.

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I also disinfected on the strong side. 1/2 gallon per 60 gallon tanks. Too much. Dead is dead. After that it's just time consuming to get rid of the chlorine smell. I think I could have done it with 1 cup per tank and left overnight. I went through every faucet and let is sit. Then, I used the drain plugs on my tanks which went right into the bilge. My bilge pump is way faster and more robust than the pressure water pump. Plus, it cleaned out the bilge.

I ran it through my hot water tank. That was kind of the canary in the coal mine for determining when the tanks were sufficiently rinsed out. Even a tiny concentration of bleach in hot water is obvious. I thought I was done rinsing until I sent water through the HW heater.

Run the solution through everything, including the vent. Slow the tank fill way down so that you can run a trickle out of the vent for several minutes. Our vents are out the transom and tend to get mud wasp nests in them. I don't know how hygenic wasp homes are, but I gave them a good shot of the solution to clean them out (one required a poke with a wire). All subsequent tank fills get the slow down to make sure the vent is running clean.

We drink our tank water (having filled on city water at our marina). We have a little Britta filter pitcher that is generally used, but mostly because it is small enough to fit in the fidge door so that we have cold drinking water. We also have bottled water onboard, but save that for taking to the flying bridge or on dinghy adventures.

I have a 50 gallon tank aboard Seaweed. When I used to fill at a dock or via jugs from shore, or by pumping out my dinghy through a filter into my tank... once the tank is full I add 1/2 bottle of hydrogen peroxide. I have sweet smelling and fresh tasty water. This may be because I use the water versus letting it sit for ages in the tank. Primarily I make my own water.

Aboard our 40'er we had two inline whole house filters. Dock water went through those two filters before it entered our tank. I thought that was a good idea but have no easy way to implement that aboard Seaweed.

I read that bleach is bad for aluminum tanks. Started using white vinegar. Then through charcoal filter. Use an RV in line filter filling the tanks.

lghawk said:

Hi Everyone,

I know this may seem like a stupid question... however I am new to this

I have a 750L fresh water tank on board the boat. I will never use this for drinking water - just for showers, washing up, washing hands, etc etc.

So my question is - how do I keep the water "clean" and free from bacteria? Do I need to even bother? Do I put chlorine in there at all?

Interested to hear what you guys all do!

Cheers,

L

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We are at Brooklyn, we fill with good old Sydney tap water at the marina. That`s it, nothing added. We don`t drink it or plan to, for drinking water we start with 10L supermarket water packs and refill, with Sydney tap. I think we could drink water from the tanks, it looks and smells fine, but haven`t, largely out of habit arrived at with a previous 1981 built boat.

BruceK said:

We are at Brooklyn, we fill with good old Sydney tap water at the marina. That`s it, nothing added. We don`t drink it or plan to, for drinking water we start with 10L supermarket water packs and refill, with Sydney tap. I think we could drink water from the tanks, it looks and smells fine, but haven`t, largely out of habit arrived at with a previous 1981 built boat.

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Our, new to us, thirty year old boat has SS tanks, I did the minimal/mild bleach clean option and drained the tanks via the drain points, rinsed and repeated several times each.
We have town water at the marina.
Then installed a Bunnings inline charcoal filter at the galley sink into a seperate drinking water faucet, then into a Brita filter jug. Tastes fine!

I do both boat and motorhome fresh water tanks using the recommended 1/4 cup of unscented bleach per 15 gal capacity. Best to mix in a few gals of water to add it in or add it spiwly as the tank is filled just to get it mixed more uniformly.
I run it through everything including the water heater. Let it sit 8 hrs but usually over night or more then start using, draining and flushing. The water heater is the toughest to flush and sometimes its easier to just drain the WH after an initial flush of the cold water and then it refills with clean water.
My feeling is if there is anything growing in the it will also be in the WH and needs to be sanitized same as the rest of the system.

We carry 200 gallons of fresh and never use shore pressure. Always pump from the tanks and gladly drink from them. Our heads flush off of them and we shower off them too so we turn the tanks in about 2 weeks (basically living aboard this summer). We shocked and cleaned our tanks per Peggy's recommendation when we bought her and now just add a few oz of treatment with each fill. We used to use Aquabon but lately we've used CamcoTastePURE. We don't use much.

Our marina water comes from an artesian well so it's basically free bottled water on tap. Just preventing it from getting nasty.

lghawk said:

Hi Everyone,

I know this may seem like a stupid question... however I am new to this

I have a 750L fresh water tank on board the boat. I will never use this for drinking water - just for showers, washing up, washing hands, etc etc.

So my question is - how do I keep the water "clean" and free from bacteria? Do I need to even bother? Do I put chlorine in there at all?

Interested to hear what you guys all do!

Cheers,

L

Click to expand...

Practical example from experience: We have boated for 30+ years. We pump freshwater into our tanks and drink that water. We have pumped water from TX, WA, FL, BVI, FWI, Antigua, Portugal, Spain, France, Italy, Croatia, ,some Greek Islands, Turkey, Malta, Gibraltar, Canaries, St Lucia, and have never had an issue with hose water. We wash the boat first and then fill the tanks. We do not have filters, but we will not fill our tanks if we don't like the smell of the water (Poros in Greece).

Water stays in the tanks these days for several months. It is already chlorinated at city supply. We have no qualms about drinking it.

All that said, we had a Brit crew help us with a Transat and they did not like the taste and so we bought cases of bottled water for our W-E Transat for them. By the end of the trip the bottled water ran out, and they did not complain about the boat water. Of course after a long voyage it was all WaterMaker water not hose water.

If you start out with clean tanks IMO you have nothing to worry about.

~A

There are many different water treatment products available, but ultimately what your tank is made of will determine what you can use. One rule: Do not use any product with chlorine if you have aluminum tanks.

I have had excellent results with

Aquamira water treatment, it is pricey, but no odor, even able to use the ice in my bourbon, of course after the second who cares

Cleaning Water Tanks

Only use to recommission the system annually (on in the event it
becomes contaminated, requiring sanitizing). Adding a little to each
fill is a very bad idea...so is too much or too little, left in too
long or not long enough. Here are the directions for re-
commissioning...they conform to section 10.8 in the A-1 192 code
covering electrical, plumbing, and heating of recreational vehicles,
and 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 re-commissioning is complete.

Ice-makers should be left running to allow cleaning out of the water
feed line; however the first two buckets of ice_the bucket generated
during re-commissioning and the first bucketful afterward--should be
discarded.

1. Prepare a chlorine solution using one gallon of water and 1/2 cup
(4 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. (There's
an easier way: just use 1 quart of bleach/50 gal of water).

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.

While bleach (chlorine) IS corrosive, it's effects are are
cumulative. So the effect of an annual or semi-annual "shock
treatment" is negligible compared to the cumulative effect of holding
chlorinated city water in the tank for years. Nevertheless, it's a
good idea to mix the total amount of bleach in a few gallons of water
before putting it into either a stainless or aluminum tank.

The cumulative effect of carrying chlorinated water is far more
damaging over time than the occasional shock treatment. And it's that
cumulative effect that makes it a VERY bad idea to add a little
bleach to each fill. Not only does it damage the system, but unless
you add enough to make your water taste and smell like a laundry,
it's not enough to do any good. Even if it were, any _purifying_
properties in chlorine evaporate within 24 hours, leaving behind only
the corrosive properties.

Thankyou so much for the feedback everyone! The advice is great and I look forward to trying some of the tips!!!

Cheers,

L

On our sailboat we used the blue Camco RV filter on the hose as we filled the tanks. Then we had those blue filters on the supply lines in the boat. And, finally, we had a two stage GE filter system under the gallery sink with its own faucet for drinking water. We did that for six years and never had any trouble at all. The total annual expense for all the filters was less than $100. Cheap insurance. We’ll be installing the same type of system when we finally find our trawler.

Doing some catch up reading. In our former boat, as some suggested, drinking water from the tank was rare. On our current boat, we learned a couple of tricks.
First, have a hose dedicated to the water tank, in its own container, ends joined so nothing but potable water goes in.
Second, before attaching the hose, run the dockside outlet for several minutes.
Third, attach an RV filter to the hose - taste, odour & particle filter - filter water going into the tank.
Last, installed an additional T&O filter & faucet in the galley for drinking or coffee etc.
Result, the Admiral will drink water from the tank!
Do we carry bottled water on board - we do. Keep a bottle or two in the fridge.

JDCAVE said:

There was an earlier thread on this so search around. I’m on limited 3G so really can’t search. The Head Mistress has some good advice on this topic. I used 4 gallons of bleach to 350 gallons of tankage for 4 hours. That’s on the strong side. You need to run it through all the taps but not the hot water tank. Remove the diffusers from the faucets. Then of course you need to fully drain the tanks and fill and run that water out. It takes me the better part of a day to complete the task.

If you do this once a year and have carbon filters on the system, you will find the water is as good or better than bottled.

But search for that thread. Lots of info.

Jim

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How big is your boat if your fresh water tank is 350 gallons?

Everyone has there own thoughts on this topic.
I just use fill my tanks with Adelaide tap water then use it for showers, washing and drinking. I try to use up each tank completely every month at least, before refilling.
No filters, bleaches or other treatment. If I want bottled water I fill a bottle from the tap and put it in the fridge. It tastes great. No reason to complicate it unless you a filling with bad tap water.

Having an old uncleanable fiberglass tank

When I bought my 1981 Marine Trader in 2007 its main water tank was a fiberglass holding tank that was under the queen bed in the aft cabin of about 250 gallons. It was also insulated with foam insulation. There was no way to clean it. It is used only for washing and showering. We bring bottled water for drinking. Lately it has been very difficult to find fresh water in the Gulf Islands. Some marinas are shutting off their water taps or having one tap only and restricting water usage.

Now that I am fully retired I am thinking of installing a dedicated drinking water day tank directly under the kitchen sink of about 60 liters made of polypropylene. There would be a deck fill using a standard water fill plate, a pull out spray nozzle right by the sink and it could drain into the bilge during cold weather if I am away from the boat in the winter.

The expensive part would be buying a portable Rainmaker osmosis water maker so I would be fully independent.

Do any of you guys have a separate day tank for drinking water?

grahamdouglass said:

Do any of you guys have a separate day tank for drinking water?

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Yes, I do. 45 gallon with separate fill and filtration.

Note: You can buy a Zero Water pitcher type filter for drinking water, coffee tea ect. Cost about $25. It really does produce 0 ppm water. No need to carry bottled water and no need to worry about "tank taste". It comes with a tester. When water gets to 5ppm replace filter.

I can attest to much of what was said with a few caveots. First of all chlorine and alum tanks don't get along. Our water tank developed little pin hole leaks over time. we now have a custom fabricated poly tank by duraweld and boy is it nice. at our marina we use dock water to fill our tank with no additives. usually once a year I do the bleach shock treatment and a long flush. we also have a drinking water filter fro drinking water and a uv filter on the tank water and one on the discharge side of the watermaker. Our water never tastes funky and we run thru it fairly quickly.

I don't understand the reluctance to drink from a boat's potable water system. This is the very definition of "potable water". Yes, if it's been neglected or filled with bad water, you might have to clean it up a bit. People mentioned Peggie Hall's book and that is a very good resource for how to clean a boat's potable water system and how to keep it clean.

We have been drinking, cooking ,showering and cleaning from our boat's potable water system since we bought it in 2008 with no issues. We make sure we put nothing but good, clean, treated water in and we add an once or two of chlorine bleach to each tank if we are unsure about the water. If a marina's water smells, we won't put it in our tanks, but even this would pass in time.

It's important to use only a "drinking water safe" hose to fill the tanks, to let the water run for a few minutes before beginning to fill the tanks and to never leave the hose out on the dock where a dock neighbor could use it to wash his boat or rinse out his holding tank.

It is expensive, inconvenient and wasteful to buy, transport and drink bottled water and once you have drunk it, you have to responsibly dispose of the plastic waste (empty bottles). Even if you think you are being "green" by putting them in a recycle container, you are contributing to pollution. There are many legitimate uses for plastic, but single use water bottles is not one of them.

Flush out your system, "shock" it with bleach, being sure to get the bleach solution not only in the tank, but in all the water lines, rinse and then fill your tanks with clean treated water and use it like you would use water at your home or business. Have it tested by the county health department if you are still worried about it.

BTW: If I offer you a bottle of water from my boat, it will have been filled from the boat's potable water system. We keep a few water bottles and refill them a few dozen times before discarding them.

A very small % of my water supply is actually used for drinking. For that I like to buy gallon jugs of spring water. Very inexpensive and a few gallons lasts quite a while. I do drink from the water tanks occasionally and don't worry about it. I also like to have the bottled water as emergency use if I run the tank dry. My capacity is only 40 gal, but if I have a few gallons of bottled water as backup, it can get me through until I can re-fill.

Can I add some comments, as my company does AWWA (American Water Works Association) sterilization of water lines for schools, hospitals, nursing homes, etc.? Just trying to dispel some misconceptions....

1. The AWWA procedure calls for 100 ppm of chlorine for 3 hours. That equates to about 1 quart of Clorox per 100 gallons of water. Run to all fixtures, let sit 3 hours, then flush. We've done this procedure hundreds of times followed by multiple sampling for E. coli and have never once found a positive E. coli result.

2. I don't like the vinegar idea. Tap water usually contains very little organic material, so it doesn't support the growth of much bacteria. Bacteria need organic material to grow. Vinegar is an organic acid (acetic acid, CH3COOH). Vinegar will not kill bacteria at low doses, but it can add enough carbon to promote bacteria growth over time.

3. The ZeroWater system might remove dissolved solids (TDS) down to zero ppm, but that has nothing to do with bacteria, etc. It does not remove bacteria, just dissolved minerals. I personally think drinking water with zero minerals is not great, but do as you see fit.

4. Filtration (unless rated at less than 0.4 microns) will not remove bacteria. It makes people feel good that they filtered their water, but it doesn't remove heavy metals or bacteria. A 0.4 micron filter will not flow much water, nor will it kill any bacteria downstream. A carbon filter removes taste, but it also removes chlorine from the tap water, so I don't use carbon filters. I'm more concerned about nasty bugs (bacteria) than taste, quite frankly.

5. Chlorine contact with aluminum is potentially corrosive, so make sure not to overdo the 1 quart of chlorine per 100 gallons, and don't chlorinate too often. It's even corrosive to stainless steel, but not significant for short contact times like the 3 hour procedure.

If it were me, for non-drinking water tanks, I'd chlorinate once, then add small amounts of chlorine every few weeks if the water starts smelling a bit.

Our previous boat had a UV fresh water sterilization system (12 VDC) installed by the previous owner just after the pump and charcoal filter. It worked very well and we always had good tasting water.

https://www.buyultraviolet.com/mighty-pure-uv-water-purifiers-3-20-gpm

This would be an option for someone looking for additional comfort about bacteria in the water supply, but it shouldn't replace the other good advice mentioned here.