Household Water Storage & Tanks: regulations, standards, products, and your problems

Household water storage is essential for approx 2 million Australians domestic needs. IE that’s the 6-7% of households depending on source of us who are not provided access to a clean safe reticulated and treated water supply.

Many home owners with a reticulated supply are adding tanks to collect roof water to supplement supply and save on water bills. Many new builds across Australia now require a minimum size of water storage/tank to be installed as a condition of the building approval.

The market is worth hundreds of millions each year. There are many different products and multiple suppliers of products.

Do you have an experience to share about the product at your home? Has it failed or created a problem? Has a supplier or their product been a disappointment?

The following experience raises several concerns.

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@jdarcy please keep us informed on how this progresses.

I’m trying to resolve an issue involving widely distributed domestic water tank liners that appear, according to lab testing of water in both tanks and its sources, to be leaching toxic hydrocarbons into the water. The company simply refuses to accept it’s even happening despite being provided with the test results, and the NSW government is engaging in the biggest game of bureaucratic ‘not my job’ duck shoving that needs to be experienced to be believed.

I wish you the best of luck in gaining traction.

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The following information will be familiar to some of us. Likely useful to know there are standards for others wondering about how it is:

All water tanks sold in Australia have to comply with AS/NZS4020:2002. This standard specifies requirements for the suitability of products in contact with drinking water, with regard to their effect on the quality of water. These products include all items such as pipes, fittings, components, and materials used in coating, protection, lining, jointing, sealing and lubrication applications in the water supply and plumbing industry. Polyethylene tanks also have their own manufacturing standard, known as the AS/NZS4766:2006, which covers all aspects of a tank’s design and manufacture.
Rainwater tank buyers guide - Renew

We are also on rain water - concrete in-ground tank, and smaller gal backup tank. We are looking to add more storage (poly tanks the lowest cost) and the options to repair the existing leaky 44,000l concrete tank which was poorly made 30 years past. A liner is one option. I prefer the concrete as it helps to balance the pH of the rain water.

I would also be concerned about why my rainwater was acidic and what else might be in it.

To reduce the ability of acidic water to dissolve metals and minerals you can raise the pH by putting a block of limestone in your tank. It will last for years and is quite harmless.

My area has reactive clay soil which persuaded me to use polymer tanks as galvanised don’t last well and concrete is at risk of cracking as the ground moves with wetting or drying. Other than faint sun damage on the top they are as good as new after 20 years.

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Rainwater is naturally acidic, with pH usually around 5.3. It is a natural phenomena.

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I wasn’t very clear. I meant if it is more acidic than would be expected due to pollution.

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Which company and which liners?

What are these hydrocarbons and what is their concentration?

The liner material is made by Gale Pacific, the liners are made by Fabric Solutions. The latter is of ‘we’ve sold thousands and never had this problem before so it can’t be the liner’ fame and the former just doesn’t want to know. When I pointed out that it’s no guarantee that they don’t have one now and that problems are by definition in some measure often unexpected, otherwise we’d pro-actively engineer them out out everything before they happen, they revert to their feedback loop. Ditto when I point out that certifications are only a snapshot and don’t guarantee manufacturing anomalies.

Also tested and found to have no detectable hydrocarbons: Water tanker and stand pipe (in tank with delivered water) and charged pipes (roof collected rain water). Both tanks have liners and delivered the results below.

I’ve done the round of Federal and NSW and all agree hydrocarbons in drinking water = bad but none will investigate. Following a letter to my local MP the matter was referred to NSW Fair Trading Product Safety, and while they were initially enthusiastic their approach was clumsy as they hadn’t bothered to read the provided results or emails trails carefully enough to have a proper grasp of the issue, and also had to have relevant standards brought to their attention by me. And then as if by magic, as soon as the NSW state election was over they declared the matter closed after providing a detailed response that was factually incorrect. They also don’t seem to understand that my primary concern isn’t one of getting a refund but one of public health and safety.

Division of government portfolio responsibilities exists for good reason but in this case the paralysis is extraordinary.

Results: (LOR is limit of reporting ie concentrations below this level won’t be detected)


Thanks for that it clarifies quite a bit.

Hydrocarbons are found in many places, driving or working near engines that burn them and many other activities will expose you to them. You cannot live in our society without exposure. Each hydrocarbon has its own toxicity. The listed categories could cover dozens if not hundreds of compounds and isomers of various levels of toxicity. You will note that only a few categories were actually detected.

Unless you can get an analysis that specifies the individual compounds (which would be expensive) and compare that to public health acceptable exposure limits you cannot make any conclusion about how much exposure to toxic chemicals you have or the health risk you are experiencing. Just because some hydrocarbons were found does not mean there is a problem.

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Yes and that’s why I tested all of the sources, I wanted to see if these compounds existed anywhere other than in the tanks, which might have been a good outcome as if they were in the charge pipe at least I could say with some certainty that the source was probably airborne and landed on the roof. Also the tanks are relatively sheltered, in a rural area with little traffic, and the nearest thing that might be a contributor is the flame from an LPG water heater about 8m away from the tank inlets.

I agree that there are some challenges, for example there’s little to no data on an acceptable level of hydrocarbons in drinking water because, as everyone agrees, it’s simply not supposed to be there.

I think what was as galling as the government paralysis was that despite presenting a smoking gun at my own cost, thinking both companies would be keen to investigate, they simply stonewalled and adopted a ‘not my problem talk to the hand’ position. I should add that tests taken over time produced the same results. Further, Fabric Solutions offered to manufacture one replacement and monitor it in the tank, to which I agreed, but then when pressed after many weeks of it not arriving reneged because ‘someone has to pay for it and no one wants to’.

An alternate approach could look to Aust Standard 2070-1999 “Plastics materials for food contact use”.
Like many useful standards consumer access is limited due to paying customers.
Free access may be possible, depending?

The standard is frequently referenced by a number of well known suppliers of poly water tanks and flexible liners intended for storage of potable water. Consumers are reliant on being provided with written confirmation of the standards a supplier’s product complies with.

I will assume your storage system has contamination, noting this hasn’t been proven.

You have made the assumption that it must be the tank liners. There could be numerous other sources such as lubricants, pumps (inc if they are hydrocarbon fuel based), pipelines, valves and the list goes on. It is worth noting it could even be cross contamination from other sources and not from within the storage system. An example being a contaminated sample bottle.

A thorough investigation would need to be done by some expert in the field of water quality and water storage systems. They will be able to take samples of each potential point source, have chain of custody, test each sample by a recognised testing authority and assess the results. They will use their expertise to identify if there is a problem, and where there is, its source.

This may require many samples taken from different surfaces and locations to determine if the results you have are representative or an anomaly.

Government agencies won’t be interested in taking a test result from a layperson who thinks they may have found something. It doesn’t prove anything, just a sample when tested showing presence of hydrocarbons.

Keeping it simple, and looking at what the average home owner is capable of achieving,

  1. Is the most significant plastic component by wetted surface area and contact time the tank liner?
  2. How does the condition of tank water from a lined tank compare with water from a different storage? Assumes both have been collected from the same roof over a similar period of time.

As you suggested there are other things to take account of. If the other sources/explanations are the significant factor, would the results be very similar for two different storages?

It would not be absolute proof if the two sources consistently provided different results. However a significant difference would support a suspicion the liner is the source due to leaching.

I’d be further interested in knowing what the acceptable upper limits of contamination are for the broader classifications of hydrocarbon contamination. BPA’s have been a focus, with several poly and tank product suppliers indicating their feed stock is BPA free. To note the same moulding equipment or fabric production lines are often used to produce industrial grade product. These will use a grade of more chemical resistant blended polymer. It may not be good grade compliant, but have other enhanced properties. Even a small amount of cross contamination or error in process change places the good grade products at risk. It’s not impossible to have a batch failure that escapes detection as it might only affect a small part of the total production run.

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I think you have missed my point. So far you do not have a smoking gun that hydrocarbons are present in dangerous amounts according to current standards. For example one of the categories listed is BTEX, one component of that is benzene which is a carcinogen. Ideally we would never be exposed to it but that is not possible. There are standards for exposure but until you know the concentration they cannot be applied.

The world is full of pollutants that ideally would be zero but in practice we cannot have that and have the population and technology that we do. Even in the days of tiny populations of hunter gatherers they had to breath in smoke from cooking fires and lightning strikes. You are asking for the impossible.

So far you have no evidence that your liner does not meet food grade standards and so there is no reason for authorities to act.

I’m not about to disagree, other than to suggest:
As consumers we are on the back foot here.

  1. If it was a municipal supply there would likely be increased interest from the respective authorities in ensuring facts are established.
  2. For those of us on our own water supplies. We are the authority. Although councils, and governments still require us to meet all regulations and codes. This includes for most only using licensed plumbers for all domestic work, despite not being in the water grid.

My take:
Since we don’t pay for water utilities there are no public funds for us to call on!
I’d still expect a state level authority to provide advice for free on what are safe or unsafe levels of typical classes of contaminants. Noted some hydrocarbons are more harmful than others. Castor oil included.

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An interesting question. When I built the house I had to meet certain requirements for disposal of the water from my AWTS but since then I am required to have the equipment tested regularly but nobody cares about the disposal area. Likewise the roof water had to be disposed of - I couldn’t just have it run on to the ground. But all tanks overflow from time to time and nobody cares where the overflow goes. Also nobody cares if my tanks or roofs are clean. It looks like they are more concerned about me polluting the river etc which is a public hazard but not so much if I am poisoning myself.

Yes. However that is not quite what we have here. The question is not should the individual be allowed to use a liner but should a liner that is to be sold to the public meet given standards.

AS/NZS 4766 covers poly water tanks however I don’t know what it says as it is paywalled. Standards Australia standards in general are not enforceable unless there is legislation that says a product must comply. Various makers of tanks say water tanks have no such legislation and I assume liners are the same.

For sure, manufacturers refer to the standard as an infallible defence but the certification against the standard is point in time. Unless there’s a monitoring regime informed by risk analysis, contaminants can enter the manufacturing process at any time and remain undetected. I’m reminded of the melamine contamination of imported baby food in 2008.

Yes but it’s an informed assumption. I did test the links in the supply chain - see above - and all tested below the LOR. Several tests of water drawn directly from inside the tank via brass valves in the sidewall were conducted and returned similar results. Sample bottles were obtained from the same respected testing lab that has supplied them over many years and has the contract for testing the local town water supply and beyond. I agree, ideally an expert would be conducting these tests but I’m getting test results that are consistent and repeatable over time.

The testing regime would ideally need to be more rigorous than I can produce, for sure, and also I’m not ‘qualified’ but taking these samples isn’t rocket science. And neither are the test results trivial given that inconsistencies have been removed, results are repeatable over time, and other evidence such as the testing of nearby sources yields different results.

Important point re average homeowner.

  1. Sure is.
  2. The water in the charge pipes showed no sign of contamination, at least not above the LOR, both tanks fed from the same roof and showed the same level of contamination. Water from a nearby unlined tank drawn from a different but close by roof also showed no sign of contamination. Tanker and stand pipe also showed no returns above the LOR.

Me too, unfortunately info has thus far been impossible to find apart from this:

I didn’t say they were present in dangerous amounts, I said they were present and all advice available to me indicates they shouldn’t be. It’d be great if a suitably qualified person would state that those concentrations are fine but no one has yet been able to do so.

Yes it is. Do you think I’m asking for a contaminant free environment? I’m not, for all the reasons you’ve listed.

The water in the tanker, the stand pipe and the charge pipe have concentrations below the LOR yet the water in both tanks, which both have liners, shows higher concentrations. This isn’t a vague randomised unreliable guess or suspicion, and the approach taken is as empirical and controlled (give me some credit for doing it properly as I’ve been taking water samples for years) as a layman could reasonably make it. To say there’s ‘no evidence’ I don’t think considers the facts as detailed above but let me ask you:

  1. What in your view would actually constitute evidence and to what standard?
  2. Is it reasonably within the capabilities of a community member to provide that?
  3. If not, how do you suggest I proceed? (Do nothing isn’t an option, that’s what happened with the RAAF deseal/reseal program. And PFAS. And Firestone tyres.)

The water tank group of the ARMA an industry body offers:

A certification mark will confirm that a third party has checked and verified the product guaranteeing each condition of the standard has been met by the manufacturer. We recommend you purchase a tank that has been independently certified as this will give you peace of mind and confidence that your water tank is of the highest quality. As of yet, there are no standards written specifically for steel or concrete water tanks.

I’ve noted examples of suppliers, one of poly tanks and the other liners who offer products that are standards compliant. No mention of independent third party certification such as WaterMark would provide.
COERCO ‘Australian Standards for Reliable Poly Water Tanks
WALCO ‘Tank Liners : Walco Liners and Covers

Enforcement or exemption of requirements for plumbing work and suitable products is subject to state/territory legislation.

I’ll be looking for the Australian Standards as a minimum when looking at products for our needs.

The ABCA relies on WaterMark certification for the plumbing supplies installed with or in connection with a new property. There are some exempt items. If water storage tanks and liners are exempt as they appear to be, it would be an oversight that needs remedy. It’s inconsistent with how other products connected to or used in the supply of potable water are classified. I’ll raise that further when I have some more complete information to relate. @BrendanMays

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If you want authorities to act on your behalf in your situation there needs to be evidence that there is harm or risk of harm being done as they judge it. The motto “the dose makes the poison” is applicable.

The way that control of toxic chemicals works in public health is about establishing maximum levels of toxins that are acceptable and then attempting to ensure those levels are not exceeded.

The evidence would be in two parts:

  • a standard for a specific toxic compound that sets the maximum level of that substance, either in the water or in polymers that are used to handle or store water, and
  • a reliable measure that the level of that substance was exceeding the specified standard.

The finding that some unspecified hydrocarbons are in your water is not enough to show there is risk. The reason that the substance must be known specifically is that hydrocarbons are not one compound but a very large class of compounds with large variations in toxicity.

Do you have any correspondence from those you have contacted? Did they offer any reason at all why they would not act? If yes, may we see what they said?

Although a little dated Choice provided the following:

HDPE and LDPE were both noted as having ‘no known health issues’ when used for food packaging.

There are performance guidelines for drinking water in Australia. There is an extensive list/s of contaminants and maximum recommended levels water should comply with.

Our household has 1990’s vintage poly pipe for the cold water distribution and PVC down pipes for the rain water collection. The original specifications are unknown. It would be useful to know which harmful substances can leach. It’s also evident from several resources biological activity (biofilms) can develop on the inner walls of PE. Not restricted to PE pipe.