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I live in a city where the water supply quality seem pretty good on daily/average basis. However, it is also well known that there is a huge problem with deteriorating water pipes. My problem is that every now and then, there is a very light and brief smell of hydrocarbons coming from the drinkable tap water. I say hydrocarbons, because it smells a bit like what you smell at a petrol/gas station. But in reality, don't know what it is.

  1. How can I test my water myself for hydrocarbon presence?

  2. Where can I obtain such a test without having to spend a fortune on expensive equipment or buying "testing services"?


EDIT: 2018-07-25

I found a company that offers various test kits two of which may be used to find petroleum-like contaminants. Unfortunately these tests are rather expensive.

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    $\begingroup$ It is unlikely that hydrocarbons could leak in through corroded pipe IMO. Is the town water supply groundwater? You could look with a black light to see if there is any subtle film that glows, but that would mean quite a large concentration. The most important dissolved hydrocarbons are the volatile organics benzene, toluene, ethylbenzene, and xylene (BTEX - but usually mostly benzene or ethylbenzene). The drinking water standards are in the parts per billion range so a proper lab test is needed. Try asking the city for their testing results for the last few years. Maybe they don't even look. $\endgroup$ – haresfur Jul 22 '18 at 22:20
  • $\begingroup$ Thank you for your feedback. What is the UV light actually seeing? Unfortunately my city seem to think they have great water, but I am in doubt after having lived in several different places in this city, and also because it's in a country where all forms of corruption is rather common. $\endgroup$ – not2qubit Jul 25 '18 at 8:40
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    $\begingroup$ The link you provided is actually for an analytical testing service, not tests you can perform at home. The methods I looked at are standard US Environmental Protection Agency methods but it appears that they only provide very generalized reports, not actual concentrations. I could be wrong about that. You may be able to do better in your country depending on where you live. $\endgroup$ – haresfur Jul 26 '18 at 9:34
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This question might be better suited for Chemistry or another place, and I'm not certain Earth Science is the place for it.

Without being an expert on groundwater, water supplies, or hydrocarbons I would say this.

First of all, "deteriorating water pipes" should not lead to any smell. Certain trace metals may be leached from metal (mostly copper) tubing, but you will not smell them. Plastic tubing (mostly PVC) likewise does not cause any smell.

What you are smelling could either come from the water supply itself, and then it's a municipal problem. Hydrocarbon contamination of wells or aquifers maybe? Have you raised your concerns with your local water supplier? Are you the only one who notices this, or do you neighbours witness this as well?

Testing it yourself would be hard. If the concentrations are high enough, you could ignite them. A safer way would be to pour the water to a bottle. Do you see any oily film on top? Does this change when you refrigerate the water? When you freeze the water?

The fact that you smell it, means it is already volatilising out of the water when you open the tap, so whatever sample you take of the water will underestimate the hydrocarbon contents.

You should also consider the fact that it's not coming from the water. Possible that it's coming from the outside, and it just happens to occur (or you notice it) when you open the tap.

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  • $\begingroup$ Thanks for an honest attempt to answer. I've already considered most of what you said, and I'm sure it's from the water and not outside. The reason I mentioned the pipes, is that perhaps something has entered the pipes, especially since the city has ridiculously low water pressure. It certainly is far from strong enough be ignitable, and perhaps not even noticed by most people, since I seem have a particular good sense of smell. At then end of the day I was hoping someone could recommend some kind of water testing kit or other DIY solution. $\endgroup$ – not2qubit Jul 21 '18 at 13:20
  • $\begingroup$ I regard to where to post the question, I did not find a suitable place for this, so I have opened a proposal for a new SO/SE site. Please help to add the Environmental Safety SE proposal, by following and adding some example questions. $\endgroup$ – not2qubit Jul 21 '18 at 13:23
  • $\begingroup$ As a hydrogeologist, this is probably the best place to post this question, but the answer isn't easy. $\endgroup$ – haresfur Jul 22 '18 at 22:20
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While the best way to test for hydrocarbons in drinking water is to get a specialized test kit like the one you posted in your edit or to send a water sample to a lab, there might be a cheaper DIY way to do it. I haven't tested it but I think it is worth a try:

Detecting hydrocarbons is exactly what is typically done when detecting leaks due to broken head gaskets in combustion engines. A broken seal in the combustion chamber of the engine can push some vaporized gasoline into the coolant. Therefore, the standard way to find such leaks is to test for hydrocarbons in the fumes that come out of the coolant when opening the radiator cap. To do so they sell very cheap tests that allow you to suck up those fumes and get them to mix with a chemical reactant which changes color if there are hydrocarbons present.

Here is an example of the test: enter image description here

And in this video, you can see how it works.

If you Google "head gasket leak test", "combustion leak kit", or "block test" you will find tons of options, and you will very likely also find it also in local shops.

However, the concentrations in your tap water would be much lower than in the design application of these tests. Therefore, the detection that takes minutes in a car might take hours in your tap water. I envision that you may be able to leave the tap open with one of these tests continuously sucking the fumes coming out of the water (if any). To do so, you can put a tube from your vacuum cleaner to one end of the test device (adjusting the size and leakage of the tube so it provide a reasonable amount of suction), so it will get the fumes to bubble through the liquid as long as you want.

This is a very rough hand-drown illustration of the setup I'm describing:

enter image description here

If you get it to change color, then you will then need to figure out the concentration. That would require some additional tests, perhaps doing the same with water with a known amount of hydrocarbons added. Alternatively, you can use that evidence to decide whether to go forward with a professional testing or not.

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  • $\begingroup$ I think I can generally picture what you're saying, though think you'd also need some rubber tubing if it were the device in the video, so as to wend the gases so they are flowing upwards into the tube? Also, when you say leave the tap open... you mean turned off, correct? (Opening a tap means to turn it on in many circumstances) Or do I picture your method entirely wrong!?! $\endgroup$ – JeopardyTempest Aug 18 '18 at 2:30
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    $\begingroup$ @JeopardyTempest Thanks once more for your edits. I always review them with much interest and learn from them. With the tap open, I mean with the water running, so I guess that is equivalent to running it on. I've added a terrible drawing of the setup I'm proposing, I hope it helps to convey the idea better. $\endgroup$ – Camilo Rada Aug 18 '18 at 16:46
  • $\begingroup$ Certainly glad to be of help when useful :-) It definitely does. And put the input end right into the water stream probably gets you the best results, right? $\endgroup$ – JeopardyTempest Aug 18 '18 at 19:17
  • $\begingroup$ @JeopardyTempest I don't think you can put the input into the water. Because if water gets into the block test device it would dilute the test fluid, that is designed to react with gaseous hydrocarbons mixed into the air. Also, you might end up loosing all the test fluid into the vacuum cleaner. $\endgroup$ – Camilo Rada Aug 18 '18 at 19:21
  • $\begingroup$ Makes sense... I was sillily picturing it as something that somehow extracted the gas from the liquid. I do wonder a bit if much gas will be coming through with a steady stream of the fluid (And also I thought at first "be careful, the gas may rise and you'd not be getting it unless right near the opening"... but guess hydrocarbon gases would generally be heavier than air?) Overall, it's definitely a real creative way to try to solve the problem. Would be quite interested to find out if it works! $\endgroup$ – JeopardyTempest Aug 18 '18 at 19:35

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