Reading a Connecticut water test report comes down to three columns: the result, the unit it is measured in, and the limit it is compared against. ND means the lab found nothing above its reporting limit. A result above an EPA limit calls for a confirming re-test before any money is spent on treatment.
What do the units on a water test mean?
Most results arrive in milligrams per liter, written mg/L, which is the same as parts per million. Trace contaminants use micrograms per liter, ug/L, parts per billion. The two differ by a factor of one thousand, so the unit matters more than the digits next to it. A 5 in mg/L and a 5 in ug/L are entirely different situations.
Hardness sometimes appears twice: labs report it as mg/L of calcium carbonate, while treatment sizing uses grains per gallon. Dividing the mg/L number by 17.1 converts one to the other. Radon in water is reported in picocuries per liter, a unit of radioactivity rather than mass.
What limit is each result compared against?
For regulated contaminants, the yardstick is the EPA maximum contaminant level, the enforceable ceiling public utilities must meet. No agency holds a private well to those numbers, which is exactly why they are the right reference for reading your own report: they are the best studied line between acceptable and not.
Some lines carry a secondary standard instead. Iron, manganese, and sulfur odor thresholds exist because of staining, taste, and smell, not health. Knowing which kind of limit a line uses keeps a stained sink from being confused with a health problem, and vice versa.
What does ND actually mean?
ND is not detected: the lab looked and found nothing above its reporting limit. It is the result you want, and on most lines it is the result most Connecticut wells get. ND does not mean a perfect zero, because every instrument has a floor. It means below the level the certified method can see, which for practical purposes is the same answer.
Which results deserve action?
Three situations, in rising order of urgency:
One high result is a prompt, not a panic. Labs are careful, but wells vary day to day, and treatment sized from a single unconfirmed number is guesswork. Most Connecticut wells test fine, and most exceedances that do appear are the secondary kind.
- A secondary exceedance, like iron or hardness. This explains staining or scale and is fixed for comfort, on your schedule.
- A primary exceedance, like arsenic or uranium above the MCL. Re-test to confirm, then treat from the confirmed number.
- A positive coliform result. This one changes behavior now: use bottled or boiled water for drinking until a re-test clears, because a positive coliform result means surface water may be reaching the well.
How do treatment decisions follow from the report?
Each confirmed problem maps to a specific fix, and the map is not interchangeable. Hardness is addressed by a softener. Contaminants, iron, sulfur, and pH problems are addressed by filtration and related treatment, chosen for the specific line that failed. A vendor who quotes equipment without a lab number in hand is selling from a chart, not from your water.
That is also why the order of operations matters: test, confirm, treat, then re-test after installation to prove the number actually moved.
What should you keep after reading it?
The report itself. A folder of results over the years is the well's medical record: it shows trends, it answers a buyer's questions during a sale, and it turns the next odd taste or stain into a comparison instead of a mystery. If the report in your hand right now is confusing, that is normal, and it is fixable in one sitting.
What should you ask about any line you do not understand?
Three questions unlock any confusing entry. First: what unit is this, and is the limit in the same unit? Mismatched units cause most homeowner misreadings, and labs do mix mg/L and ug/L on one page. Second: is this limit a health standard or a secondary standard? The answer changes the meaning of an exceedance completely. Third: is this result confirmed, or is it a single sample? One number is a snapshot; two agreeing numbers are a fact worth spending money on.
Any lab or tester should answer all three in plain English without reaching for jargon. If the explanation you get raises more questions than the report did, that is not a chemistry problem, it is a communication problem, and it is fair to take the report elsewhere. The document belongs to you, the water it describes is yours, and the explanation should be too.
One habit ties this whole page together: read the report the day it arrives, with the previous one beside it if it exists. Ten minutes while the sample is fresh in memory beats an archaeology project later, and the comparison against last time is where the folder starts paying: steady numbers confirm the well's character, and a drifting one flags itself years before it becomes a finding.
If you have a result you want a second set of eyes on, or a well that has never had a baseline, book a water test and we will build the folder with you. The statewide context for your numbers lives at Connecticut water statistics.
We read every report with the homeowner, line by line, in plain English. If nothing needs fixing, the report says so and we say so.
Key takeaways
- Every line answers the same question: how much was found, in what unit, against what limit.
- mg/L and ug/L differ by a factor of a thousand. The unit matters more than the number.
- ND, not detected, is the most common and best result on a report.
- One exceedance is a prompt to re-test and confirm, not a verdict on the well.
- Secondary standards cover taste, odor, and staining, not health. Read them differently.
Frequently asked questions
What does ND mean on a water test?
ND means not detected. The laboratory looked for that contaminant and found nothing above its reporting limit. It is the result most lines on most Connecticut reports come back with.
What is an MCL?
MCL stands for maximum contaminant level, the enforceable ceiling EPA sets for public water systems. Private wells are not held to MCLs by any agency, which is why they are the standard yardstick for reading private results.
My result is slightly over a limit. Is the water unsafe?
A single result slightly over a limit is a reason to re-test and confirm, because sampling conditions vary. If the second test confirms it, choose treatment from that confirmed number. The report is a starting point, not a verdict.
What is the difference between primary and secondary standards?
Primary standards protect health. Secondary standards cover taste, odor, and staining, things like iron and manganese. A secondary exceedance is a comfort and plumbing problem, not a health rule violation.
Read your own numbers.
A certified lab report of your tap, explained line by line in plain English. If your water is fine, that is exactly what it will say. Book online, call, or write.