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

Having higher concentrations in the tank does not necessarily mean that the liner is the source. The source could be anything upstream from the water source to the tank. It could also be from first flush through the system (say from a pump, pipe, valves etc where oils/greases have been used in their manufacture or to prevent surface oxidisation until they are installed). I have seen some manufacturers in the past recommending a good flush/wash before using (like what which often occurs with domestic cooking/food handling items).

As the tank is a storage, they could have been washed into the tank and where they have ended up and where you have identified them.

This is why I recommended an expert having a look as it is very easy to jump to the wrong conclusions. You may be right, but there is a high chance that you may be wrong and could be from other sources in the system.

If you are concerned, an option might be to discharge all the water and then refill the tanks. This may flush any contaminants from the system.

Correct. In any system there are always possibilities for false positives and distortions in the testing arising from from exogenous sources no matter how the samples are drawn which is why in my experience labs provide ‘control’ results. All we can do is limit the opportunities for this to happen. However, having tested the supply chain at every point repeatedly and finding consistent evidence of contamination only in the tanks, and at the same level, constitutes at least some reasonable level of evidence or at least the level of evidence available to me to provide as a layman. Call it grounds for reasonable suspicion if you will.

I’ve attempted to engage an environmental consultant but none is willing to take on such a small job as their work is typically geared towards major projects. If you have any suggestions about how I could eliminate the variables in this situation further I’d welcome them.

Yes, I probably should’ve mentioned that I emptied and flushed both tanks before refilling one with rainwater and the other with a tanker delivery.

Hi Mark, the guidelines are what I regularly have the tanks tested for but the test profile doesn’t include hydrocarbons because…they’re simply not supposed to be in drinking water. The only reason I tested for HC is because I described the taste and odour to the local lab and they suggested it. We also tested for solvents initially but the results were below LOR.


Unfortunately it doesn’t. I’ll use a simple example of a different water storage, a dam, to explain why.

There is an empty dam. It is built on a gully where it is fed by a spring. The spring water in the gully is clean. During a storm, sediment ladened runoff from upstream areas fills the dam. After the storm, the clear spring water returns and flows in the gully. The dam is full of sediment ladened water.

Lets assume we were away when the dam filled and one wanted to know why the dam water was sediment ladened. Looking at water flowing into the dam, the water was clear. Should we then assume the water from the gully was not the source of the sediment in the dam water. It could be easy to assume the dam caused the sediment, when in fact it isn’t the case.

Likewise with your tanks. You are trying to attach test results from a past event thinking that since the tank has hydrocarbons detected in a sample, it must be the source. This could easily be an incorrect assumption like the sediment in the dam example.

But, if there was no storm, then possibly the dam could be a contributing source if there is evidence it was the case. Evidence could be from testing the soil to determine if it was dispersive based on the quality of the gully water. This could equally apply in your case, but additional evidence would be needed such as testing the surface of the liner where it hasn’t been in contact with the water (such as an offcut from installation which has been kept in the same condition as on installation/no subject to any potential contamination). If the liner has been in contact with water, it could have been contaminated with the hydrocarbons in the water (residues left on the liner surface) and as a result can’t be used as evidence.

Looking at limited test results after an event can easily lead to the wrong conclusions as outlined above.

The liner is only one potential source of the hydrocarbons. Because there is hydrocarbons in the tank, like the sediment in the dam, this does not prove the source of the hydrocarbons is the tank liners. The hydrocarbons can come from upstream sources and have been flushed into the tank, where testing shows it now is.

This is why I have suggested an expert in the field. They will he able to determine the source of the hydrocarbons from thorough sampling and testing. Unless such is done, evidence is lacking and one is jumping to conclusions.

There will be smaller consultancies willing to do the work. I used to work for one and did similar work for industries.

It is likely to cost several thousand in consultancy fees, plus cost of testing samples.

A consultant may prove where the hydrocarbons came from or could arrive at the conclusion that it is unknown. The later could occur if time has passed and there is lack of evidence to its origins.

The OP having said it is not a danger that is a lot to pay to possibly identify an aesthetic problem with no way to know the cost of the fix or even if it is possible at this stage. I would be investigating whether water filters would remove the smell.

I noted that the test results relate to two tanks. One has water from the roof (rain water). The other treated water tanker delivered.

If there are factors other than the liners in the tank they would need to be present in both sources of water. It’s possible. How likely both sources are contaminated with C6-C10 hydrocarbons? It’s more challenging to explain away compared to a single source single event scenario.

Irrespective of the source there are health guidelines available on the levels of BTEX.
Water supply health standards are noted in the following.

For the petroleum group hydrocarbons associated with petrol and diesel. Someone might be able to provide further reference to a reliable source/s. I’ve read several resources reporting on environmental water quality that variously group C6-C9 or C6-C10, C10-C14 as well as TPH. There are toxicology profiles updated by the CDC for the commonly measured groupings.

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I don’t think I actually said that, apologies if I gave you that impression. I guess if I thought it wasn’t a danger there’d be no issue. I said HCs are potentially harmful but there appeared to be an absence of hard data on the harmful levels in drinking water, and the concentrations that are present may or may not be of concern but the consensus among those suitably qualified is that HCs in your drinking water is not good. The link helpfully provided by @mark_m will be keenly considered.

Yes they can and the possibilities reasonably open to a member of the public have been exhausted but also this isn’t a complex supply system with hundreds of moving parts. I have some appreciation of and training in objective forensic interpretation of data and wanted to believe it’s not the liners hence I was hoping I’d find HCs in the charge pipes as that would indicate an environmental factor but (somewhat alas) they were found to be below the LOR.

Every part of the supply system and its sources have been tested separately and the presence of HCs, only after both liners were installed, is conspicuous. Where does a member of the public, having spent considerable funds on testing, now turn to seek assistance in obtaining ‘proof’ and how much should be required before authorities act or at least investigate further? It’s easier to say why something ‘mightn’t’ be the case than to prove that it ‘is’ as the possibilities for ‘explaining away’ are endless but if that was the default position and no one acted on reasonable suspicion the world be a much less safer place.

Given you have professional experience in a related area please tell me what you’d do if you were in this position.

Yes initially the contents of one tank was rainwater and the other tanker water. Both returned HC results of similar magnitude. The charge pipe water (roof), tanker water and municipal stand pipe from which the tanker draws were found to have HCs below the LOR. The tanks were emptied and refilled with tanker water and HCs were again detected. One tank was emptied and refilled with rainwater and again found to have HCs present. All HC concentrations were similar irrespective of the combination of water source or tank. It seems the only common factor is the liners.

Amazing, thank you. Not sure how you found this but I’ll be looking at it very closely :+1:

Saw this last night, yes there are differences but there are also parallels including the community having to go to unreasonable lengths to get traction and the company responsible claiming it’s not them and resting their argument on questionable data. The comments by the EPA CEO were interesting in that he expressed surprise that residents had to provide their own tests. That’s possibly because initial approaches to the EPA weren’t taken seriously, it appears that for things to get to this point community frustration must’ve been high.

Depending on how far one might go.
One thought would be to have a sample of one or both liners cut out and sent to an accredited laboratory for testing of the liners against the Australian Standards the supplier claimed the product met. The sample size, collection method etc would need to meet the criteria of the lab.

It may be worth looking to include a portion of any seam or lap joint where there has been a hot welded, heat cured or solvent based joint. Usually the first two in my experience.

This would leave one with an in situ patch repair and require the tank to be empty or partially empty.

The assumption is the liners will if the source return positive results for the hydrocarbons detected when tested to the standard. Whether the results meet or fail food grade or other standards is a matter to discuss with the lab who will need to be certified for the tests required. It will have a cost. Get a quote if serious before committing.

It’s not unheard of out sourced suppliers to provide a compliant product as a contract sample. What may subsequently be supplied can differ in properties for a number of reasons. Some unintended, others deliberate. At the scale of many imports to Australia the cost burden of routine random sampling and testing is often greater than the competitive margin. Taking an OS based manufacturer to court is expensive and with uncertainty of financial success.

The following was the part that had me confused and guessing that the problem was a matter of smell or taste. There are municipal water supplies that smell or taste terrible that are still supposedly within Oz drinking water standards.

Finding the cause of the problem does not look certain and may be expensive. If the cause is found the cure may also be expensive.

Have you considered if a water filter may deal with it cheaper, quicker and more certainly? There are such things on the market that will remove hydrocarbons.

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I fully appreciate that you have spent much time and effort on the issue.

As I outlined above, carrying out a few tests only proves that hydrocarbons have been detected in the tank water. It doesn’t conclusively indicate that it is from the liners. It isn’t conclusive as there are a number of other sources where the hydrocarbons could originate.

While the supplier of your liners only states the liners are membranes and I can’t find the material specifications, most tank liners available fall into the plastic family of materials. The type of plastics used are inert (don’t react with water) nor leach compounds into water at room/ambient atmosphere temperatures. This might be why the company who supplied the liner shows no interest in addressing your concerns further.

Any investigation needs to remove potential sources of origin (eliminating potential sources rather than testing to point to a particular conclusion). Having a point in time sample from a system only shows the quality of water in that point in time. It does not show whether the hydrocarbons existed in the system prior to the liner being installed or from other sources upstream of the tanks.

While the tank liners could be the source, equally they might also not be the source of the hydrocarbons. For example, hydrocarbon compounds are often recommended and added to control mozzies in tanks. Have such materials been added to the tank in the past?

As many hydrocarbons are sticky (tend to stick on surfaces), they could be present in the system for some time or have been added by other means and residuals present in the system - which you have measured.

As I suggested, rather than getting bogged down in what should be done, what potential sources could be etc, as I have indicated above and if you are interested in trying to identify the source with potentially pursuing further, I suggest that you commission a specialist consultant in the field to see if they can determine the source of the hydrocarbons.

The will look at the system and potential sources of the contamination with open and independent eyes. They will also he able to determine what hydrocarbons are present which is useful when assessing potential sources. They will also be able to determine the materials/compounds used in the system and hopefully identify where they might have come from. Such assessment won’t come cheaply. If it is found that the liners or another is the point of contamination, then you know where you stand and will have that support of an independent consultant to assist you should you need to take it further.

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Ah yes I see. I can’t say for certain if the levels are harmful so I didn’t, but not knowing is part of the dilemma. If someone had authoritatively stated the level of contamination was perfectly fine I’d be at least happy on that front.

For sure. I’m running a carbon cartridge filter at the moment and it’s definitely made a difference to smell and taste. Feel free to suggest something else you know of.

I think I’d characterise it as more than just ‘carrying out a few tests’ as there was an informed methodology underpinning the approach. And I agree it’s not scientifically conclusive otherwise in the strictest sense but it does pass the reasonable evidence test.

If a car tyre or pram wheel or ladder fails it could be hypothetically attributed to any number of causes such as operator error, harsh treatment, incorrect use etc but that doesn’t mean there’s no issue, and a layman wouldn’t expect to pay for a possibly inconclusive engineering report before going back to the retailer. Firestone tyres is one such case where legitimate concerns based on reasonable evidence went unheeded.

Firestone had more information about tire failures than Ford did because of warranty claims, but Firestone never acted on this information because it always blamed consumers for not maintaining their tires correctly or operating their vehicles in extreme environments, leading to these failures.

Lawyers and traffic safety researchers decided not to contact the [National Highway Traffic Safety Administration]because they lacked confidence in the agency and feared that an investigation might conclude that there were no defects, thereby compromising existing personal injury lawsuits.

The mine article reminded of my own experience when the community spokesperson suggested that the EPA hasn’t seen this before so they don’t know what to do with it. This is exactly my experience in that all of the experts I consulted suggested that the testing approach was sound, the logic was sound, but it wasn’t anything they’d dealt with before and not in their lane. Fair Trading sent it to the EPA, the EPA sent it back, and Fair Trading said they can’t do anything more which it were it remains for now.

I’ve asked previously what extent a layman should reasonably have to go, noting complete denial and lack of assistance from the supplier, before their case is taken seriously by product safety agencies. Commissioning a report from a consultancy is cost prohibitive for most (probably greater than new tanks). I spare a thought for people who have legitimate product safety concerns but aren’t in a position to tackle the manufacturer or the bureaucracy even this far, albeit apparently for no gain, and folks simply shouldn’t have to stump for a report worth several thousands of dollars before their case is taken seriously noting that even a scientific report won’t necessarily be conclusive depending on who’s arguing against it.

So given my situation ie informed evidence exists but it’s not scientifically conclusive and such testing is cost prohibitive and may or may not yield results, I defer to your experience in the industry. What would you do?

Spot on and that’s what this one claims. However, very few manufacturing processes are 100% safe and this is the issue with the manufacturer claiming that it starts and stops with their certification which is point in time only. Oh, and since they’ve never had the problem before they can’t be having it now. There could be an entirely innocent reason for all of this such as the rollers on which the material is manufactured being maintained with the incorrect lubricant, but either way this is a food grade product and contamination is what it is.

Indeed. Somewhat like having point in time product certification is no guarantee against future contamination. All in can offer as a layman is to say that the taste and smell commenced immediately after the liner was installed and the test results over 6 months are consistent including using different sources and emptying/refilling tanks in that time. As I wrote previously, there are thousands of reasons that this could be explained away but it’s not typically how risk is managed in any arena.

No, good thought but under the circumstances I’d immediately be suspicious of anything remotely like an additive and would’ve pursued that.

Yes, sad but true. It seems that even though this is a food grade liner the controls amount to all care and no responsibility. The absence of any particular interest on behalf of both parties is conspicuous, as was the liner manufacturer’s acceptance and then withdrawal of an agreement to investigate further by installing a replacement liner to see if the results differed. Then of course there’s the consistent line of ‘we’ve never had this problem before…’ It seems to me these companies are well prepared to stonewall until compelled to do something, usually by the law, and they know full well how hard that is for anyone in the community to orchestrate. Just ask the folks near the mine.

It isn’t an EPA issue. This is why you would have received this response by incorrectly contacting them for something outside their jurisdiction. If it was hydrocarbons in a watercourse or in soil, they may have showed some interest. If it was in a watercourse, they might have done some further investigations. If it was in soil, the EPA would have provided the same advice as I did with your water tanks. That being commissioning an independent expert to assess its origins, risks and management.

The EPA may not have known who jurisdiction it falls under and why they may not have referred you on. Product safety comes under Product Safety Australia.

You are being judge and jury based on your own interpretation of limited results.

I suggest that if you are unwilling to get independent assessments of the source of the potential contamination in your water collection and tank system, there is little more we can assist you with.

I didn’t contact them, Fair Trading did (see above). Thanks for the tip re Product Safety Australia, they were contacted 12 months ago but it’s a black hole as they provide no feedback whatsoever on whether they’re taking interest in a matter.

Enough folks that are suitably qualified have indicated that this case is worthy of consideration so I’m satisfied that it passes the reasonableness test. YMMV.

I haven’t stated that I’m unwilling. However, it is cost prohibitive to obtain the type of evidence you’re suggesting is essential. Cost shouldn’t be a consideration where product safety is concerned.

That may be the case to examine further to see if the liner caused the hydrocarbons in the water. I would be very surprised that they agree your conclusions based on the presented information.

I will try and explain why it is premature to jump to the conclusions you have made.

Say for example the tank water was tested regularly and happened to be tested the day before the liners were installed and the day after the tanks were filled. Say the day before, no hydrocarbons were detected but the day after they were. This I assume many would say is unequivocal evidence the liner is the source of the hydrocarbons in the tank water and the liner must be faulty … and the manufacturer is therefore responsible. You have tried to draw similar conclusion from less information and have made assumptions on what the limited testing means.

But is it conclusive evidence that the liner is the source of the contamination. Unfortunately no. It may be, but there could be other sources of contamination. It can’t be ruled in, and likewise, can’t be ruled out.

Some other sources (off the top of my head) include the cleanout and preparation of the tanks, storage conditions and handling by others from factory to installation, the installation process, post installation cleanup, chemicals/tapes/glues used for installation and I am sure there are many other potential sources.

Until all sources of contamination are ruled out, the source can’t be confirmed. As it appears that a preinstallation test wasn’t done, this means the number of additional potential sources of contamination increase…such as the hydrocarbons being present in the tanks before installation occurred and upstream sources.

I have been involved in carrying out regulatory testing of onsite waste water treatment systems for clients and am familiar with investigations on the sources of or reasons for contamination in these systems. Often contamination comes from unlikely sources/reasons, and one needs to methodologically assess potential entry points of contamination in a system, whilst finding evidence to rule out sources to narrow down the potential source(s). At times the process is straightforward, other times sources are unknown (such as one off events where there is insufficient data to ascertain the source with any confidence).

Doing investigations is a relatively specialist field. One needs to understand the history, the contaminants and possible sources including their chemistry. This is why if you want to confirm where the potential contamination comes from, is to commission someone with the necessary expertise. Guessing the potential origin from limited testing and some assumptions won’t assist you taking it further, and will likely result in doors closing which appears might be already occurring.

Have you had the filtered water tested? It may be clear and the problem solved.

Detecting pollutants in the filtered water by smell or taste may not be reliable. Humans can perceive what they expect to perceive, especially if highly invested in the outcome. This is an observation of human behaviour (confirmation bias) not a personal comment.

The smell and taste is actually what alerted me to a potential issue and led to having the water tested. Yes the filtered water has also been tested and found to have lower concentrations but the smell and taste remain.

If the filtered water was below the LOR I’d be much happier but that’s only half of the problem as my other driver has always been the broader community safety aspect. If I’m right about the liners being the source it means that thousands of people in rural areas are similarly affected. Government agencies all genuinely state they’d like to do something, and feel there are grounds to do something, but can’t because unfortunately it’s not in their portfolio responsibilities so nothing is done. The spokesperson for the community near the Cadia mine expressed it perfectly when she stated words to the effect that ‘they just didn’t know what to do with it’.

I see that might make you happier but would that make you any safer?

Depending on the methods used the LOR is a different number and no value in isolation says anything about the risk of harm. If you went to another lab their LOR might be different. The number has no intrinsic significance, it is just an outcome of the technology and procedure used in detection. Different methods give different numbers.

Indeed. All very true but for a typical layperson in the community it has to start somewhere, as it did with for the folks near the mine, or a potentially serious and widespread problem just gets buried.

Further story on Cadia. It appears that the community only gained traction due to pure chance and random events unrelated to their stated concerns; one arising from an air quality study required in support of a mine extension, and another during the course of a platypus study. Had these not occurred, that same group would probably still be struggling to be heard.

This sort of thing happens all the time and mostly you hear nothing about the ones who don’t get lucky. It takes a combination of facts, reason, clever publicity, lobbying, momentum, timing, dedication and pure luck for environmental activism to succeed. It is never simple and never easy.

For every individual who stands against a perceived environmental injustice and wins there are a thousand who fail, the few winners learn how to do all the things required which is rare and takes years. The losers all failed for the lack of any one of the required conditions being met.

If you assume that all you need is to do assemble the right facts you are destined for heartbreak.

Well organised groups have a slightly better batting average as they can combine disparate skills and support each other. I am saying this not to be negative but to be realistic.

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