SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Cleaning a fresh water tank - how?

7K views 24 replies 16 participants last post by  SailNet Archive 
#1 ·
Hi All...

I now have my first boat that's not a dinghy and find that there is just tons and tons of stuff I don't know. Well I expected that, but here is a really simple thing that never occurred to me.

Today, I tried out the foot pump int he galley and it spit out brownish purple "water." I was able to locate the fresh water tank and it seems to be in for good.

So, how do I clean it?

Thanks...
 
#2 ·
Tank

The previous owner may have winterized the tank and used some kind of diluted anti-freeze, or the brownish stuff is just debris and god only knows what. I would try using regular house hold bleach mixture with water. let sit in the tank, and then flush it out with fresh water several times. If all you have is a foot pump (no mechanical pressure pump) you may want to see if you can access the top of the tank through a cap and wash clean the inside, and flush the water fill hose, and pump, and water lines. Thats my two cents.
 
#4 ·
Thanks for the tip!

I'm sure this is the fresh water tank. Its under the cockpit astern, while the holding tank is under the vbirth next to the head! And of course I have a bunch of head related questions, but I'll save that for another thread.

I suppose running a bleach solution through it would kill stuff, but would it get the fill line and the top of the tank?
 
#5 · (Edited)
Bacteria/mold etc in the water tank can cause that... a heavy dose of bleach, and flushing the tank several times will help clear it. You should probably also follow up the bleach shock treatment with several tanks of fresh water and then one of water/vinegar and then several more of water.

Let the vinegar/water mixture sit, since it will help neutralize any odors in the system.

I would also recommend, if you have an access hatch, to scrub the water tank's innards and replace all of the hoses.

The bleach will kill most of the stuff in the deck fill hose and the top of the tank, if you fill it so that water is pouring out of the vent. :)
 
#6 ·
I would rinse out a few times before adding the bleach. This is for a system with a pressure pump, but I'm sure you can adapt the procedure. It takes a lot of rinsing so you want want portable electric pump for this. You can get a 110 volt version at the hardware store for not too much money.


Turn water heater off at the breaker before beginning. Do not turn it
on again until entire recommissioning is complete.
1. Prepare a chlorine solution using one gallon of water and 1/2 cup
Clorox or Purex household bleach (5% sodium Hypochlorine solution ).
With tank empty, pour chlorine solution into tank. Use one gallon of
solution for each 5 gallons of tank capacity, which results in 4
Ounces of bleach for 10 gallons of water.
2. Complete filling of tank with fresh water. Turn on every faucet and
allow water to run until what's coming out smells strongly of bleach.
3. Turn off faucets--but do NOT turn off the pump...it must remain on
to keep the system pressurized so that the solution remains in the
lines. Allow to stand for at least 3 hours, but no longer than 24
hours.
4. Drain the tank through every faucet.
5. Refill tank with clean fresh water and drain again through every faucet.
6. 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
(iow, go sailing and tack a lot).
7. Drain tank again through every faucet, and refill with potable water.
 
#7 ·
Thanks guys. If I can get into the tank I'll scrub it and if I can get to the hoses I'll replace them. Better safe than sick. I think I can get to all the hoses from the tank to the pump and faucet, but the fill hose may be tricky.

I did notice that the local ships store had a variety of hoses in stock, so at least I can find them.

If I can;t get to the tank, lots of bleach and viniger...

Thanks very much!
 
#8 ·
Hey - don't forget to change or installl an dunder-sink water filter from your local home depot. I think they only run $20 and HOLY COW what a difference they make!

I've tried the bleach (which works great) on my own boats, and I've tried the vinegar to follow up. The vinegar was FOUL even after flushing, and I had to replace some hoses. I even tried a baking soda / water solution which dissolved good but still didn't kill it all off.

Make sure you pump the bleach up to the pumps and unti it comes out of the faucets or else it will all be just sitting in the tank.

Do you have hot water or a recirculating system, or is it old-fashioned pump from seawater and freshwater tanks?
 
#9 · (Edited)
Hey - don't forget to change or installl an dunder-sink water filter from your local home depot. I think they only run $20 and HOLY COW what a difference they make!
That's a great idea, thanks!

Do you have hot water or a recirculating system, or is it old-fashioned pump from seawater and freshwater tanks?
Nothing that elaborate. I don't think there is a water heater at all. Just a tank with a fill hose running to the deck, and another hose running to a foot pump and from there to a faucet. Or maybe its better described as a nozzle.

The sink appears to drain to a fitting in the hull.
 
#11 ·
Be aware that most of the under sink filters are designed to work with treated water, which the water in many freshwater tanks are really going to qualify as. Also, if you don't have a pressure water system, the filters aren't going to be very useful.
 
#12 ·
Are you sure the foot pump is for the water tank? Many boats have a foot pump that brings in sea water for a salt water wash that you follow with a fresh water rinse. Seawater can really get funky pretty fast sitting in the hose. You might have a sea water foot pump. My boat has both fresh & seawater foot pumps. The fresh water foot pump is fine but the seawater foot pump does stink & we don't use it.
 
#13 ·
inspection port

Hello,

IMHO, if your tank doesn't have an inspection port, you need to add one. After seeing (and cleaning) the inside of my tanks, I don't believe there is any way to really clean the tank without getting in there and scrubbing.

The tanks on my O'day came with inspection ports. The tank on my Newport did not. It was pretty easy to add one.

Good luck,
Barry
 
#14 ·
fresh water

I have a 1976 Oday. The water tank is a 12 gallon 1976 water tank. I am the third owner. A basic water and Clorox rinse 9 years ago when I bought the boat made me feel more confident but I decided to use the tank water for dishwashing and hand washing etc,etc. I have a two gallon Rubbermaid jug for drinking water and some extra 1 gal. cider jugs. On a recent twelve day trip to Lake Champlain the jugs supplied all the drinking water and the 12 gallon tank took care of chores, with three refills from the lake and from marina hoses for the 12 gallon tank. BTW, I have an electric pump-faucet and that movers a lot of water at a time so I was rather profligate with my fresh water supply. But drinking water came from known, pure supplies kept in portable bottles.
 
#15 ·
This is very helpful to me as well. I am new to the sailing after 35 yrs. and just bought a bayfield 25 this month and live in Nova Scotia, so I have to learn a lot in a short time in order to winterize as well. The previous owners have been extra helpful but live a distance away and cant have "hands on " to show me everything.
Judy
 
#18 ·
I wouldn't think you really would need to replace the fill line. In normal installations, water would never sit in it like it would the supply line from the tank to the sink.
 
#19 ·
Depends on where the fill port on your tank is. If it is at the bottom of the tank, then the last few inches of fill hose can get very grungy...
 
#22 ·
Repeated use of chlorine bleach is not a good idea for aluminum tanks, but a properly done annual shock treatment shouldn't be a problem.
 
#24 ·
Bi carbonate of soda (baking powder) is also used to clean out fresh water tanks.

I've seen that black stuff (usually black mold) formed inside the water inlet pipes even on quite new boats, the transparent inlet pipes and the sloshing water really encourages it. Whereas it's not so keen on the submerged areas. Maybe you can get a long bottle brush to tackle the inlet pipes.
 
#25 ·
In a fiberglass or plastic tank, you can add a teaspoon of bleach to each gallon of water put in the tank. It will keep mold and bacteria from forming, but may taste/smell bad. The undersink filter from Home Depot will take out the smell and deliver good water for drinking, coffee, etc. Leave the bleach in the hot water lines, it will sanitize your dishes and won't hurt when you wash your hands. DO NOT do this in an aluminum tank! An annual chlorox shock and cleaning, followed by thorough flushing, will not destroy the aluminum, but long term exposure to bleach (even in small concentration) will. Every few years you will want to do a mechanical scrub inside the tank, whether plastic or metal. A gasketed screw-in deck plate can be put into the tank easily. My tank is 100 gallons, aluminum, horizontally mounted in the bilge, with two baffles in it to cut down on sloshing. I had one access hole, and after I cleaned as much as I could reach, I cut in two more access ports between the baffles with a sabre saw. There was an inch of crud on the bottom of the tank between the baffles! Until I bought the boat, the tank had never been properly cleaned in 25 years! I do an annual inspection, chlorox shock and flush, then keep it pure with an iodine based sanitizer. This routine is probably not as critical for a live-aboard, due to the higher usage, but as a weekend warrior and laid up for 4-5 months in winter, the water tanks can get pretty gross.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top