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Drinking water storage in caravans


#1

I wonder about the safety of drinking water storage in caravans after reading a post related to a brand new van’s drinking water having a strong metallic taste. The water was stored in a metal type tank that came with the van. Apparently the owners and other owners of similar vans were told to wash the tanks out vanilla water and or a product from BCF, branded Camec- trisodium phosphate but the taste was still evident. What are the checks and balances for these types of products?


#2

Hi Iris

I would suggest that it doesn’t matter what sort of drinking water container you buy, whether it’s a small water bottle, or a multi-hundred litre rain water tank, if you are going to drink from it: clean it out before you use it. Even if after manufacture it was cleaned out, you don’t know how long it’s been stored, and in what conditions.

In this case, I’m assuming you are talking about a stainless steel water tank in the caravan. If you Google, there are many ways to clean out a stainless steel water tank.

Chlorinated Trisodium Phosphate used appropriately in the right concentration as a cleaning agent would seem to be harmless, but beware it can stain metal fixtures and adds phosphate to the waste water system when rinsed out.

Finally, make sure that you fill your drinking water tank with a food grade hose, not a garden hose. Garden hoses can be the cause of the strange taste you mentioned.


#3

Without some details it is hard to say. Caravan water tanks are often plastic, stainless steel or aluminium which would be safe if clean. Why the water should taste metallic is impossible to say without knowing where it came from and how it was treated. It may be the tank itself but without more evidence you cannot say. Common causes of problems with stored water are it wasn’t clean to start with (eg bore water) or algae have grown in it.

To me reticulated water in country areas tastes horrible due to the amount of chlorine but I am assured it is safe and many thousands drink it. So taste is not a good indicator of safety.


#4

Apparently one of the concerned caravan owners stated the water was "pure rain " water with no taste until it was in the caravan tank and other owners of that particular brand of caravan also complained about the awful taste which became worse as days wore on. So my question is are these tanks tested for safety re the tanks do not leach chemicals into the water either from the tanks material or from the welding materials used to join the edges, if so who does the testing?


#5

The caravan industry is notoriously unregulated; so the answer is no one. Have a look at discussions on caravan warranties on this forum and what lemons they can be in relation to caravans.

How did they get it from the rainwater tank to the caravan? How long was it sitting in the caravan? When was the last time the caravan’s water tank was cleaned?

I’ts quite possible algae grew in the caravan’s water system, especially if the caravan was nice and hot from being in the sun.


#6

An often overlooked fact is rain water is typically not pure H2O.

Even in a pristine and perfect world CO2 is absorbed by water in the atmosphere, which results in - edit “carbonic acid” being formed. (not carbolic acid - auto spell checker at work). So natural rain water is typically a pH of 5.6, compared to pure demineralised water which has a pH of 7.0. Any metals or related compounds whether in piping, tanks, or the other contaminants the water touches on the way to the tap can dissolve or leach into the water to add flavour!

Given all the other stuff in the atmosphere including dust and Sulphur there will be even more impurities in natural rain water than we imagine.

While we have supposedly pristine rain water not being on town water, our water does come off a metal roof, and is stored in a large concrete tank. The calcium in the tank walls helps to neutralise the acids ensuring a better pH above 7.0, the solids settle out, and it tastes great! To be safe though the water is filtered in two stages, UV sterilised and the drinking supply given a third filter stage.

We could chlorinate it in a number of different ways, but that does change the taste in our view.

Town water gets treated to remove solids, nutralise acids, remove contaminants and adjust the pH, add flouride etc etc. It also has a residual level of chlorine to ensure that bacteria does not grow in the pipes or any subsequent storage. It’s not good to store any water long term without some level of protection and treatment.

P.S. There are recognised standards for food grade materials to be used in water storage vessels. These include cleaning, and sterilising with chemicals and procedures that are marketed to meet these standards. As others seem to be saying you also need to be confident what you are then putting into the storage tank in the caravan is of suitable quality. The topic of cleaning and passivating stainless steel or aluminium water storage tanks is technically involved.

A responsible caravan supplier and manufacturer should be able to demonstrate through their QA procedures that their tanks meet food grade standards, otherwise does it pay to be cautious using them for a drinking supply?

Note that legionella thrive in the temperature ranges (above 20C and below 50C) the water in many caravans may experience. There may not be the thermal mass as for of a large household storage tank to keep the temperature below the recommended 20C for cold water.

Hopefully there is some good advice out there about cleaning and sterilising caravan water tanks on a regular basis. You would expect it is also in the van owners manual?


#7

Nitpick: carbonic acid. If you have carbolic acid in your rainwater the pollution is terrible and you should move away.

Good point. The manufacturer should be able to show the tank passes.


#8

@Iris, regarding the checks and balances, there are Australian Standards for water and plumbing systems that show manufacturers the correct way to build water systems. A standard can either be voluntary or mandatory. If the standard is vountary, there is no legal requirement for a business to follow the rules or advice set out in the standard.

As others have mentioned, the caravan industry is largely unregulated. It also appears that any applicable standards related to water storage and plumbing systems for caravans are also voluntary and therefore unenforced. Although, please note that I am not a standards expert, so for the record please check with Standards Australia or even the Caravan Industry Association for more specific advice.

In any case, our safety system often only kicks into gear after something goes wrong and CHOICE is currently campaigning on this issue. If the caravan water tastes funny, it might be worth digging into the materials used and whether the manufacturer followed the voluntary standards. It might also be a good case for installing a water filter into the van (in addition to following the cleaning tips listed above).


#9

Quite right, the auto spell check corrector is to a similar standard as my proof reading!


#10

It also contains cyclic salts…airborne salt from sea spray that can travels a long way inland. These salts fall out onto the roof catchment or come down with the rain.

Roofs also can have contaminates such as dust, pollens (or other vegetative matter), animal excrement etc which can also affect the taste and composition of rain water.

House plumbing can have plastic (poly pipes) or metallic (copper or galvanised steel pipes) taste after water has sat in the pipes for some time. Hot water stored in hot water systems can also have a taste as the heat can remove some of the aromatics which can flavour water…a taste one becomes accustomed to.

As outlined above, for any new water storage used for human consumption (pipes, tanks ot even reusable water bottles), it is always best to wash the storage with a detergent to remove any residues present from the storage’s manufacture.

After this any impact on taste will most likely be from low use of the storage (and aggravated through storing water in the storage rather than storing air dry) where the water has been sitting for some time. The water could loose aromatic volatiles (chlorine is an example) which will make the water taste different and possibly other background tastes then dominate. An experiment to do at home is to boil the water and see how the taste changes when the volatile compounds present in the water are removed through the heating process (best to use say a clean stainless steel saucepan to boil the water as it will have no impact on the taste of the water). The boiled and cooled water tastes very different to the same source, fresh tap water.

Also, every water supply in Australia has different tastes which result from the source (i.e. groundwater v surface water, forested catchment v disturbed catchments) or the method of treatment. If one is travelling with a caravan, the taste of the water will change as one moves around the country. Some of these tastes can be earthy, metallic, etc as well.

The other thing is human taste buds are very sensitive to different tastes (what I understand is an evolutionary thing to protect us from eating bad food). A small amount of residual water from another water source or which has been stored for a long time can taint the taste of the remainder of the fresh water added.


#11

We always leave our tanks filled. Apparently less likely to have a build up of gunk. Any water we add to our tanks goes through a filter before entering the tank. Any drinking water we use from these tanks is filtered by the under sink filter. In the 25+ years we have been travelling with such stored water there has never been a problem

Rain water is far from pure. When we moved into our new house from the country where we lived on rain water (and a bore) we used rain water for drinking until we realised we had planes flying over on their way to land and decided that their exhaust wasn’t that healthy. We looked at filtering it but the high cost made us decided filtered reticulated water. Our rainwater is used for the garden.


#12

I guess the people posting on the caravan forum were saying their rainwater didnt have a metalic or other taste and were asking if others had experienced similar outcomes in relation to caravan water storage tanks. Other people responded stating they had no trouble in some vans but in a certain brand they experienced the same taste after a day becoming worse on day three. My query was is there any testing of these tanks and by whom?


#13

Brendan that was what some people seemed to be doing and some found the taste was lessened whilst others said they only used the water for washing in, using a large plastic container of water brought specifically for that purpose for drinking water.


#14

@meltam the post said the water had taste after the first day becoming worse by day three. The posters mentioned they cleaned their drinking water tanks out regularly.


#15

From a caravan specialist that supplies replacement tanks, tank cleaner and water treatment chemicals to reduce odour and metallic tastes in van water!

A common problem?
The same supplier also sells replacement poly water tanks. At a guess if a van has a metal tank that has some age and that may not have been suitably manufactured, there are options?

P.s.
Pure demineralised water with a neutral pH of 7.0 is almost undrinkable to some of us.

For any chemical products used for cleaning drinking water supplies or treating drinking water, look for clear user instructions, a SDS for the product and any Australian Standards certifications or compliance statements.

There is a limited range of food grade stainless steels (premium for certification) which also require specialist fabrication skills. Cleaning and the essential passivation adds cost. It may be that some vans with metal tanks have lesser materials and were never passivated which leaves them exposed to corrosion?


#16

That is an interesting point. “Good” water is not really pure despite advertising campaigns. It has some dissolved gasses and solutes. As long as they are the right gasses and there is not too much of either.

But we drift away from what Iris really wants to know. Sorry Iris there really isn’t a definitive answer. We don’t know enough about the particular case and as others have said overall regulation in the industry isn’t too good.


#17

Drinking water from a caravan tank is not usually a great idea, as the above comments reveal.

However no-one has mentioned the use of a filter. In my van I have a filter inserted in the cold water line, so when drawing water for drinking or coffee/tea/cooking, a lot of the impurities are removed. A lot of people fill their van tanks through an in-line filter as well, which is a great idea to help reduce the amount of unwanted particles and flavours getting in in the first place.

Those chlorine tabs sold for cleaning out such tanks leave an overpoweringly chlorine flavoured water which takes many flushes of the tank to reduce it to an acceptable level. Kinda defeats the purpose, especially when you have a spouse with chloring allergy :slight_smile:


#18

It is unlikely that algae would grow in the water system, unless the tank or piping is translucent, as algae need sunlight to grow. What might grow easily when the tank and piping are hot and wet is fungus/mould.


#19

I fully agree that a water filter should be used when the tank water is used for drinking or food preparation.


#20

What might easily grow in water that is stored in an untreated tank are bacteria. Fungus and mould are all around us, yuk, but not necessarily going to kill us.

Bacteria can breed readily in tanks in the dark. It only takes a few to start it off and a few to get into our systems and life is worse than miserable.

You cannot filter out bacteria (RO may be the exception). They need to be exterminated. Chlorination products, boiling for extended periods, or UV sterilisation are all options.

All our in house roof water is UV sterilised before use as well as pre filtered. No chemicals required.

Consider the following nasties:

  1. Escherichia Coli. Escherichia Coli (also known as E. Coli) can cause nausea, vomiting, abdominal pain and diarrhea if consumed in contaminated water. …
  2. Campylobacter Jejuni. …
  3. Hepatitis A. …
  4. Giardia Lamblia. …
  5. Salmonella. …
  6. Legionella Pneumophila. …
  7. Cryptosporidium.

There are a number of online resources available in each state for recommendations on the safe storage and use of rain or tank water. The general requirements appear applicable to storage in a caravan tank.

Some official looking and useful sources of information that may assist understanding of the issues:

https://www.health.gov.au/internet/main/publishing.nsf/Content/0D71DB86E9DA7CF1CA257BF0001CBF2F/$File/enhealth-raintank.pdf

https://www.nationalpolyindustries.com.au/2018/06/15/is-it-safe-to-drink-rainwater-from-water-tanks/

There is the option of only drinking tea, to not brush your teeth and use only prewashed lettuce leaves.