Blue well water 6

[beach004]

There's been one previous thread on this, but it was not dispositive, so I am trying for help. I live in Piedmont North Carolina, on a well: Unfiltered, untreated. It's been tested, none of the numbers out of whack, pH not low; but the water, when seen in a white five gallon bucket, has a distinctly blue tint; and the toilets and sink will get a blue ring around the drain and the rim, over time, that nothing, not even muriatic acid, wants to dissolve--I have to scrub it out with lavastone. I do have copper pipes; the house is 14 years old. Anyone have a clue?
Beach004

 

[bimr]

Blue or blue-green stains on sinks, baths and porcelain, indicate that there is probably copper in the water supply. Copper is usually from the corrosion of copper plumbing. The amount of copper can be found by sending a water sample to a lab for testing.

From memory, the previous thread was asking about water colored blue, not a blue stain on a fixture.

What is the basis for your comment regarding "none of the numbers out of whack, pH not low"? What are your comparing your water analysis to?

If you want an evaluation, why don't you post the numbers. Numbers are needed for hardness, TDS, alkalinity, and pH.

 

[bimr]

Looked at the other thread again involving blue well water, and the problem was most likely caused by the water softener.

Water softeners will remove all of the hardness, unless you bypass a portion of the flow and blend the flow back together. If one removes all of the hardness, then the softened water will tend to be more corrosive. The corrosive water will corrode the copper water pipes. So the water softener fixes one problem and creates another.

Copper piping by the way is not very resistant to corrosion.

I recall visiting a town in IL that had so much copper corrosion from the water, that the wastewater treatment plant was having a hard time meeting the discharge limit for copper. Unfortunately two different utilities were involved, a water utility and a wastewater utility. The water utility did not want to spend the money to raise the pH so the wastewater utility was having discharge permit problems.

 

[beach004]

I'm sorry--I didn't have the analysis at hand when I wrote originally; now I do. Here are the numbers:
Hardness: 22 mg/l
Copper: 0.12 mg/l
Alkalinity: 38mg/l
pH 7.1
TDS I don't have a value for.
The lab indicated no problems with the sample. As I said, there is no water softener. My own background is as a chemist, but organic; so I'm out of my depth here.
Hope this will enable one of you to make an informed judgment.
Beach004

 

[bimr]

Your pH is on the low side and as a result, your water is mildly corrosive. A measure of corrosivity is the Langelier index. There are many free online calculators that can be used to determine the Langelier Index:

http://www.cleanwaterstore.com/technical/water-treatment-calculations/langlier.html

Raising the water pH will decrease the corrosivity of your water. A pH level of 8-8.5 will probably eliminate the corrosion.

The most common method to raise the pH is to use a chemical feed system and feed a sodium carbonate solution. Sodium carbonate is a mild alkali so that there are no major concerns for handling of the chemical.

http://www.water-research.net/corrosion.htm

Here is an example of a municipality adding sodium carbonate:

http://www.cityofsalem.net/export/departments/spubwork/operations/water_services/cc_installed.htm

http://www.clemson.edu/psapublishing/pages/WATER/WQL5.PDF

In summary, if you really want to correct the problem, investigate the use of a sodium carbonate feed system to raise the water pH to 8-8.5.

 

[beach004]

This suggestion will require some thought. Since my water is totally untreated now, I would have to add a system from scratch, at a cost to be determined. Might it be cheaper to replace the copper pipes?

The copper number seems low, but I feel sure the sample was taken after letting the water run, so that's not a good indicator of what could be in it, when it's stood in the pipes all day or all night, I wouldn't think. My principal concern is that the corrosion will eat away my pipes entirely, which would certainly be expensive to remedy.

Thank you for the expert advice, bimr!

 

[rconner]

Not professing any expertise here, but I'm not sure it wouldn't be a bad idea to do some further research, at least before ripping your pipes out of your walls. While I have not run any aggressivity indices and I would not be surprised if your water is some aggressive from what information you have supplied (and as apaprently suspected from other posts, before you provided the analysis); however, it perhaps would be a shame if good pipes are ripped out of your walls, and even more of a shame if this somehow did not solve the blue/stain etc. problem that apparently started the discussion!
I did notice there is a phone number listed at the site

http://www.copper.org/copperhome/Env_Health/environmentandhealth_drinkingwater.html

that could conceivably be a helpful resource (or who could direct you to one).

 

[rconner]

[btw I am guessing that the blue well water sample you have talked about is not directly from the well, as the subject sort of infers, but instead was drawn from somewhere in the house after traversing some significant length of piping. Advise if that was not the case -- also, it might be interesting in any case to get a visual or analysis sample from close to the well, if that is possible.

 

[beach004]

Now THAT is an excellent idea! The sample for analysis was, as you inferred, taken from an outside hose bib, but by then the water had been through a good run of plumbing, at least some of it copper. But if I recall, the pump has a bib on it, and I could fill up the telltale white plastic five-gallon bucket from it, without the sample having been anywhere but the aquifer. I'll see about it tonight. Thanks!

 

[bimr]

Replacing the copper tubing would tend to be expensive. I would wait until leaks appear.

In many parts of the country, PEX is now accepted in lieu of copper tubing.

 

[beach004]

OK, I took the concrete cap off my well, and inside, as I remembered, was a hose bib; on the threads, significantly (I think), was blue-green stain. I hooked up a hose, let it run five minutes or so, and then collected a five gallon bucket of water, to compare with an identical bucket obtained from inside the house (1) of water that had stood in my pipes for 8 hours, and (2) from water that had been running for ten minutes or so. Bottom line is, I cannot see any difference in the color of any of the three samples--they all have a definite though faint blue-green color.

So, I'm about 95% satisfied that the color originates in the ground, whatever it is. (The only minor unknown I have, is how that well bib works; what triggers the pump to run, when the water has not yet been through the pressure tank, under my house? Could that water somehow have been up to my house and back rather than straight from the ground?) Since the analysis doesn't indicate any hazardous materials present, and since my pipes don't leak (yet), unless anyone else has a new line of inquiry, I guess I will declare victory. Thanks to all,
Beach004

 

[bimr]

Copper in drinking water can be derived from rock weathering, however the principal sources are the corrosion of brass and copper piping. The taste threshold for copper in drinking water is 2 - 5 mg/l. The US EPA has proposed a maximum contaminant level (MCL) of 1.3 mg/l for copper.

It is possible that the copper is from the raw water, but unlikely.

Here are some sampling techniques:

http://www.maine.gov/dhhs/eng/water/Templates/Rules/LeadCopperSampling-Site.htm

Why don't you get your well water tested for copper?

 

[beach004]

I'm not averse to getting the well water tested for copper, but a question: When I had my house water tested, two years ago (results above), the tester got the water from an outside hose bib; I was not here, but I assumed he would have let the water run before collecting a sample. Would I be right or wrong? And if he did let it run (I will call the agency tomorrow, and see if they have an SOP for sample collection), would the resulting sample not pretty much represent the well water? If not, then can I get a well-water sample, if, as I did yesterday, I go out to the well and take a sample from the hose bib inside the well housing? Or should I take two samples, one from an overnight "sit" so to speak, and one from the well?
As a one-time chemist, albeit organic, this is almost fun!
Beach004

 

[bimr]

Not sure that you should assume anything. One would think that the correct location for sampling is where the water is used (kitchen sink for example), not the hose bib. The hose bib is a dead end and not frequently used, so it would not be a good place to collect a sample. So the fact that the sample collector took his sample from the hose bib would indicate that the sample collector was not knowledgeable about taking samples.

This Nebraska document is very comprehensive:

http://www.ianrpubs.unl.edu/epublic/live/g1360/build/g1360.pdf

Basically it states to run the cold water tap for about 2 minutes until the water sample is cold. That would indicate that the water lines have been flushed out. Then take a sample.

Wait 6 hours, and then take a sample of the water that has been motionless in the pipes.

If you go to all the trouble of sampling, I would take a sample at the well in addition to other sampling locations. As the article states, copper is rarely found to be naturally occuring.

 

[beach004]

Wonderful! That reference is really valuable. So, it looks like I'll need to take at least three samples to test for copper. Am I correct in thinking that "22mg/l hardness as CaCO3" means I have soft water? And pH = 7.1, combined with that, suggests a somewhat corrosive system, you said.

Next question: As a (former) chemist, is there a reliable test kit on the market that I could buy and do this testing myself? It might be less of a hassle than trying to get the Public Health folks to sample and analyze for me--the first time was pretty tedious. Besides--it could be fun!
Thanks again,
Beach004

 

[bimr]

Am I correct in thinking that "22mg/l hardness as CaCO3" means I have soft water? Yes

And pH = 7.1, combined with that, suggests a somewhat corrosive system, you said. Yes

Next question: As a (former) chemist, is there a reliable test kit on the market that I could buy and do this testing myself? It might be less of a hassle than trying to get the Public Health folks to sample and analyze for me--the first time was pretty tedious. Besides--it could be fun!

No, the amount of material that you are testing for very minute which makes testing difficult. It is not something that you can do yourself. The testing is done with a Spectrophotometer.

There are many independent labs, you do not have to go to the health department. Check the phone book.

Here is a water lab:

http://www.e-watertest.com/water-testing-equipment.html

 

[beach004]

I don't know it enough folks are following this esoteric thread to welcome an interim report, but: I did order a copper testing kit, before bimr wrote me; and today I bought a spa pH kit, and just now measured the pH: I'm getting a reading below 6.8. That being the case, I suspect I know the answer, I just don't want to accept it! Let's see if the copper test confirms it; if so, I'll have to do something to raise the pH (getting back to basics, so to speak). Oh, well.
Beach004

 

[beach004]

I talked just now to the local health department that did my test, two years ago; the water sample was collected after a five-minute run, so it's ground water. They confirm that, with the very low alkalinity of my water, even a pH slightly above 7 would still be corrosive. So I'm looking at neutralizers--and at my bank account! This looks likely to cost me a thousand bucks, plus periodic maintenance. I wonder what the economics might be of replacing the copper pipe with PEX, instead? Anyone?

 

[beach004]

Amazing, my copper-testing kit from National Safety Products, ordered Friday, was here Monday. The results, in light of other data, are not surprising: Water in my pipes that has stood overnight was off the scale, >2ppm; water I ran in the kitchen for a couple of minutes was 0.4; and the bathroom shower, after two people showered, was 0.1, right in line with what the Health Dept. got, two years ago on a five minute flow.
So I'll have to get a neutralizer--replacing copper with PEX would be around $4500, doesn't make sense economically. Installing the neutralizer doesn't look like a DIY project, not in the crawl space. Good thing my stocks are doing so well, I can readily afford it...Right!

 

[bimr]

Noticed your reference to a "neutralizer" and not sure what you are referring to. A neutralizing filter will only raise the pH to about 7. So a neutralizing filter will not make a difference in the corrosion. You need a chemical feeder to add an alkali to raise the pH.