Why Well Water Testing is Necessary

Ever go to the refrigerator thinking you’re going to make yourself a wonderful, healthy omelet, only to find your ingredients aren’t at their best? Maybe the eggs are past their expiration date (do you take the chance?), the peppers are kind of soft, the mushrooms are shriveled (ick!), the ham slimy and smelly (eew!), or the cheese moldy (okay maybe that one you can overcome with a sharp paring knife). The point is, you started out with the makings of a perfectly good omelet, but over time and through really no fault of your own, you have something you just wouldn’t eat. Ah shoot, maybe you should have taken stock before that last trip to the grocery store.

Water Test

Water testing is necessary.

Turns out your well water is no different. You may think you have perfectly good tasting, even healthy water but maybe you don’t!  In fact you can’t know for a fact what is in your well water without periodically taking stock.  You just can’t tell without a water test.

Perception is Not Reality

For a majority of well-owners, the only time a water test is done is when the well is new (just drilled) or new to them (moved into a house with a well). Even in these circumstances, not all jurisdictions call for mandatory testing.  After that first test, all is presumed to be well. A common belief goes something like this…“I’ve never had a problem. We’ve never been sick and it’s always smelled good.” One university study from Eastern Canada study reveals the myriad reasons that this belief is risky business. Most of the households in the study were very confident in their water source, and as a result, some of the wells had not been tested for over 30 years!

So what was revealed when the researchers went in and did the testing for them? First of all, 9 of every 10 had full confidence in their water source. But turned out, 6 in 10 actually had a problem with aesthetic or health-related contaminants. With regards to bacteria, 40% of the wells were found to have total coliforms in the summer sampling and 60% in the fall sampling. (We’ll come back to the seasonal differences.)

You Can’t Always See, Taste, or Smell the Problem  

It is true that turbidity and color may signal bacterial contamination of your well water. May.  Of the samples that exceeded color guidelines, 2/3 had bacteria present. And coliform bacteria were present in just 50% of those that had high turbidity. That means that nearly 75% of the samples which were found to have bacteria in them were actually within acceptable ranges for color and/or turbidity. You just can’t tell without a water test.

Change is Almost Inevitable

Groundwater changes over time. Sometimes gradually, sometimes not.  It’s pretty obvious when there is a really fast Spring thaw or an incredible summer down-pour that causes localized flooding, and you know then to check that your well hasn’t been inundated with surface run-off.  But what about the gradual changes?  In this particular study, wells were tested for bacteria both Spring and Fall. For nearly 30% of the wells, the result was different – positive one season and negative the next or vice versa. For those that were consistent, half were negative for bacteria both times (nice!) and the other half were positive for bacteria both times (scary!). Regardless, these are the results over just one year. How can you not anticipate some change over the 10, 20, or 30 years that you are living in your home?  Seasons change.  Land-use changes.  Water quality changes.  You just can’t tell without a test.

A Well-Built Well

Remember when there were no seat belt laws? And when cars didn’t have airbags?  Standards for safety change as risks change, and as we come to better understand those risks. The same is true with specifications for well construction. Nowadays, it’s not uncommon to see newly-drilled wells equipped with sanitary well caps, grout seals, a casing that extends above ground with appropriate sloping around it, and grout seals.  All of this is necessary to best prevent bacterial contamination. A separate study from the Centre for Rural Pennsylvania tested wells all around that state. In particular, they considered how many of these “best practices” for well construction were in place and which wells had bacterial contamination. As you might expect, the wells with fewer safety features were more likely to be contaminated with coliforms and e.coli bacteria and contamination rates decreased as the number of safety features in place increased (see figure). Interestingly, though, even with all 5 safety features in place some 30% of wells still had bacterial contamination.

Well contamination chart

Chart showing well construction features and chance of contamination.

Chances are pretty good that your well was drilled at a time when standards were less stringent. You’ve likely been in your home 10, 20, even 30 years. Have you made appropriate upgrades to your well? Should you? Some deterioration in the well integrity may be obvious, but not the quality of the water itself.  You just can’t tell without a water test.

Location. Location. Location.

A USGS study that examined wells from all over the US, found that overall roughly 1 in 3 had bacterial contamination, but that aquifers in certain geologies tended to have different rates of contamination. Said another way… bacteria in your well water may just depend on the bedrock your well is drilled in. Overall, just over a third (33%) of wells were contaminated with coliforms and those constructed in carbonate and crystalline rock tended to have higher rates of detection… roughly 70% and 50% respectively.  The latter geology is found through much of New England and New York State. Unless you got this information from the driller or have your well records handy, you’re unlikely to know the geology. And it’s out of your control.  Regardless, know that the potential is there, and that you just can’t tell without a water test.

Water quality changes. Regular well water testing is the only way to know for sure if the water you’re drinking, that your guests are drinking, that your children or grandchildren are drinking, is as good and healthy as you think it is.


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