Water Tank Pollution

[Victor Echo]

I have an under cabin sole Fresh water grp tank. During winter lay up rain water flooded the bilge and bilge water complete with oil etc got into the tank. Any ideas on how I can get this cleaned up, short of removing the tank which would involve major surgery.
Brian

[Larmex]

I had a similar incident years ago and installed a clean out port in the tank so that I could use a shop vac to get all the water out and then clean and fill several times before finally using bleach in the last clean out. Caution though......if you backwash your watermaker when there is any chlorine in your water you can ruin the membranes and filters. Very costly. It took a year or so before I would use the water for cooking etc., but it passed a potability test after my 3rd washout. Good luck!

[ovrmyhead]

I had to cut inspection ports in mine to clean it out. Now that I have seen the build up of crap in a water tank I will always pack my drinking water in and use my tank for wash water only.

[GordMay]

Greetings and welcome aboard the CF, Brian.

You might try high-pressure steam/hot water cleaning, prior to copious flushing & rinsing, per the other suggestions.

[peghall]

I hope you haven't run the fresh water pump, 'cuz you don't want to pollute the plumbing too! So if you haven't, DON'T!!

If there isn't an inspection port in the top of the tank, install one...I realize that may also require cutting the sole above the tank to install a hatch in it too, but this isn't the only time you'll be glad to have both.

Using a shop vac, power washer and lots and LOTS of detergent and water--but no bleach yet, clean out the tank.

Once the tank is pristine, recommission the system (bypass any water heater and/or water maker) according to these directions:

The following recommendations conform to section 10.8 in the A-1 192 code covering electrical, plumbing, and heating of recreational vehicles. 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…bleach does absolutely nothing to improve the flavor of good Scotch!

1. Prepare a chlorine solution using one gallon of water and 1/4 cup (2 oz or 25 ml) 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. (Those are the “official” directions. They work out to 1 quart or litre of bleach/50 gallons of water , which is MUCH easier to calculate!)

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 vessel motion.

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

[peghall]

Seems to me it would be easier and cheaper just to maintain the system....

[ovrmyhead]

Originally Posted by peghall

Seems to me it would be easier and cheaper just to maintain the system....

Getting your tank clean IS maintaining your system

[SaucySailoress]

Originally Posted by peghall

Seems to me it would be easier and cheaper just to maintain the system....

What would you recommend, Peg, for maintaining the system?

[peghall]

Recommissioning it annually--preferably as part of spring recommissioning--according to the directions I posted above. That's been the approved method for marine and RV fresh water system for at least 25 years (that's how long it's been since I found 'em, and they're still being included in owners manuals).

And btw...even if you only use your tank water for washing, you ingest a LOT more of than you think you do. You wash your hands, then pick up a sandwich...rinse out a cup and then fill the cup with bottled water...wash dishes in it...brush your teeth...even showering and washing your face, you get water in your eyes, ears, on your lips. And if you REALLY want to be paranoid, there are the "germs" you can absorb through your skin!

If you thought it was ok before you saw the the inside of the tank, and it hasn't killed you yet, chances are it never will. So recommission the system annually--or at least when the water starts to smell/taste funky--and don't worry about it!

[AuroraGH]

Any tips on removing tank taste? I installed a carbon filter I found at Home Depot. It works OK but the pressure drop across the filter is almost too much for my poor foot pump to handle, I succeed only in getting a trickle of water and the return spring for the up stroke goes up very slowly.

[peghall]

Yup...recommission the system. Although most people think only in terms of the tank, most foul/funky water odor/taste actually originates in the plumbing because the molds and fungi--not algae, algae needs light--that cause it thrive in DAMP dark place, not under water. That's why it's so important to leave the pump on to keep the system pressurized so that the solution remains in the lines.

However, a foot pump instead of an electric pump makes keeping the system pressurized a bit of a challenge...don't know exactly how to solve that one...hopefully someone else does.

As for your filter, I think you must have bought an ice maker line filter instead of water filter. I suggest you replace it with a Brita (or whatever brand floats your boat) faucet filter. Just remember, though that filter isn't a substitute for cleaning out the system and that filters require regular inspection and cleaning or replacement.

[AuroraGH]

Originally Posted by peghall

Just remember, though that filter isn't a substitute for cleaning out the system and that filters require regular inspection and cleaning or replacement.

Oh yeah, agree. But even spanking clean, the water gets a kind of "plastic" taste to it that I don't much like - even just filled. Plus the wee bit o' bleach I add can sometimes be tasted. A carbon filter takes all that out and that's why I have it.

[AuroraGH]

Originally Posted by peghall

Just remember, though that filter isn't a substitute for cleaning out the system and that filters require regular inspection and cleaning or replacement.

Oh yeah, agree. But even spanking clean, the water gets a kind of "plastic" taste to it that I don't much like - even just filled. Plus the wee bit o' bleach I add can sometimes be tasted. A carbon filter takes all that out and that's why I have it.