Water Tanks Plumbing Help!!! Please

[surfingminniwinni]

We have about 500ltr fibreglass watertanks, with copper piping to galley & head sinks. The water has a horrible smell & taste. Should I rip out the copper piping & replace with plastic and then clean and flush the tanks? Or should I leave the copper piping in place & clean and fush the lot? Then just leave the copper piping in place?

Remembering this is an early 80's boat, that we have just purchased & it probally hasnt been used for a couple of years, can anyone give me an idea how to clean the tanks as well, we have a small access hole about the size of a saucer.

Thanks in advance.

[NoTies]

Are you using a watermaker?

[AnchorageGuy]

I would not start to take anything apart just yet. We have successfully used a shock treatment to clean tanks and lines very successfully. A heavy dose of bleach in the tank, put the bleach in first, then fill the tank. Be sure you run the chlorinated water through the system so all lines and tanks including the hot water tank are full. Let it set over night, then flush it good until the bleach taste is gone from the tank. You might need to flush several times, but this should cure the problem.

[Gene :^)]

Copper is used in homes everywhere, I really doubt they would be the cause of the odor. I think you should just clean the system with the bleach method from the previous post. You can also buy freshwater flush "stuff" from RV stores. I think even Walmart has it in the RV section.

Watermakers using Reverse Osmosis make great water but the water is mineral deprived and will leach minerals from the copper. Unless you are using a water maker, I would not replace the copper with plastic. If you primarily use a water maker and don't often mix it with tap water, I would replace the copper with plastic.

Just my 2 cents. Always verify information on your own.

[MidLandOne]

For shock treatment, as others have recommended, we use 135ml of 3.5% (35gm/litre) hypochlorite solution per 100 litres of water (so about 700ml for 500 litres of tankage). If in the USA I believe that your household bleach is 5%, not 3.5%, so if using that adjust the quantity down to suit.

You may need to clean filters in the freshwater pump's suction side after. You will probably need more than one flush to get the taste out of the water depending on how much organic matter was in the tanks to start with.

[DeepFrz]

Shock treatment. Sounds like a mental hospital. Check your tanks and if they are dirty clean them. You may have to use a wand with a pressure washer but get all the gunk out and off the sides of the tank. You should at least clean the pipes as well.

Why take a chance on making yourself sick. You have no idea what was put in those tanks.

[johneri1]

My experience with tanks (mostly in RVs) is that the smell is from bacteria. Bleach is the go-to solution to kill the bacteria and thus the smell.

Originally Posted by Gene :^)

Watermakers using Reverse Osmosis make great water but the water is mineral deprived and will leach minerals from the copper. Unless you are using a water maker, I would not replace the copper with plastic. If you primarily use a water maker and don't often mix it with tap water, I would replace the copper with plastic.

Say WHAT??? What "minerals" are RO water supposed to leach from copper pipe? This is an urban myth with no basis in scientific fact. Copper pipes are a perfectly acceptable means of distributing even very pure water, which water from a water maker is NOT.

RO water made from seawater by commercial water making systems is NOT low in dissolved solids. It's actually rather high in salts compared to typical surface drinking water supplies.

A typical specification for RO water from a water maker is a salt rejection of 99% to 99.5%. That means that it contains between 0.5% and 1% of the salt of the seawater fed into it. "Standard" seawater contains 35 parts per thousand of dissolved solids ("minerals"). A reasonable value for RO water would therefore be on the order of 200 to 350 parts per million.

Just to put this in perspective the MAXIMUM standard for total dissolved solids in drinking water in the US is 500 ppm. It's easy to see that while RO meets the standard, it is hardly "mineral deprived".

[Gene :^)]

I am not a scientist so do your own research. My post is nothing more than a good heads up.

I was told by Watts (the company that makes my home RO system) not to use copper tubing because the water will leach minerals and I could have a metallic taste, more importantly I could develop pin hole leaks.

If you google it, you will also find many sources stating the same.

Again, I am not a scientist or water expert. Just passing on the information I was told by Watts, whom should be a reputable source since they manufacture RO systems.

[NoTies]

That has been my experience from running RO plants for about 25 years.

[Gene :^)]

Pete, which answer are you referring to? Copper bad or Copper ok with RO?

[NoTies]

Copper bad with RO. The better the water quality the worse the mineral leeching.

[MidLandOne]

But it is dependant on resident time that the water is exposed to the copper - in normal use it is not a problem if just the pipework is copper, certainly not the very short runs in boats.

Those with a fad for safety might consider, if the water has been sitting stagnant in the pipes for weeks, running the pipes for a few seconds until fresh before drinking the first lot out of them but I don't think I would bother myself.

[NoTies]

The RO water will corrode the copper. The longer the water sits the slower the leeching becomes but it will still corrode leading to leaks. It also imparts a metallic taste in the water. At one stage I was making water <1 microsiemen and the corrosive effect was very rapid.

[MidLandOne]

Had a quick hunt and an interesting draft WHO paper here on the health effects of drinking demineralised water at Health risks from drinking demineralised water

Point out though I am nor great fan of the UN as they publish some absolute crap at times (in fact, maybe much of the time ).

I have been in a few labs where demineralised water was reticulated in copper pipes and it was recommended not to drink it because of the possibility of leeching (but they were big labs with long runs of pipe). But as far as I know, the rate of corrosion from leeching was not considered an issue - but may be different elsewhere.

In NZ, as far as I know, copper is mandatorily accepted for potable water from all sources, but how much consideration has been given to demineralised water I don't know. Also don't know how demineralised water would compare to rain collection (for which copper is approved) in so far as mineral content is concerned.