You sent a water sample to the lab. Now there is a report in your inbox with numbers and abbreviations, and you are trying to figure out whether your family's water is safe.
The three contaminants that matter most for private wells in rural Texas are coliform bacteria, nitrates, and arsenic. Here is what each one means, what the limits are, and what happens when a test comes back with a problem. No alarm-raising, and no selling you treatment you do not need. That is not how J4 Water Works operates.
Coliform bacteria
This is the first thing any new-well test looks for. Coliform bacteria include E. coli and other indicators of fecal contamination. The EPA's standard for drinking water is zero. Not low. Not trace. Zero. A private well that tests positive for coliform has a problem that needs attention before anyone drinks from it.
That problem usually comes from one of three places: a well cap that is not sealing properly, surface water getting in around the casing near the top of the well, or contaminated water in the aquifer itself. The most common source we see is a compromised seal at the wellhead letting surface water in.
The fix depends on where the contamination is entering. For surface intrusion, we shock the well with chlorine, test again, and in many cases the result clears. For a damaged cap or casing seal, we repair the failing component and retest. For ongoing contamination that cannot be resolved at the source, a UV disinfection system or a point-of-use reverse osmosis unit at the kitchen tap protects your household while the root cause is addressed. We walk the whole sequence in what to do when coliform comes back positive.
Do not drink water that fails a coliform test until you know where the contamination is coming from. That is one rule we would ask anyone to follow, regardless of who they call.
Nitrates and nitrites
The EPA's maximum contaminant level for nitrates is 10 milligrams per liter. For nitrites, it is 1 milligram per liter. These are health-based numbers, not preference numbers.
High nitrates in well water almost always come from one of three sources: fertilizer runoff reaching the groundwater, animal waste leaching down through the soil, or a septic system located too close to the well. In agricultural areas of rural Texas, elevated nitrates show up more often than most homeowners expect when they move out from the city.
Nitrates are a particular concern for infants under six months and for pregnant women. Adults at typical exposure levels face lower immediate risk, but infants can develop a serious condition from nitrate exposure. If you have an infant at home and your test comes back above 10 milligrams per liter, use bottled or filtered water for infant formula and feeding until the issue is resolved.
The most reliable treatment for nitrates in drinking water is a reverse osmosis system installed at the kitchen tap. Water softeners do not remove nitrates. Standard pitcher filters do not remove nitrates. If your test shows a problem, the treatment has to match the specific contaminant. We cover this further in our piece on what a water softener does and does not fix.
Arsenic
The EPA's limit for arsenic in drinking water is 10 parts per billion. Naturally occurring arsenic in groundwater is a real issue in certain parts of Texas, tied to the geology of the aquifer. Not every area has it, but areas with certain rock formations can see it show up in wells.
Arsenic exposure at low levels over a long period of time is associated with skin, lung, and bladder concerns. This is not a one-glass problem. It builds over time. Which means people can drink from a well with elevated arsenic for years before they know they have an issue, because it has no taste or smell.
Treatment options depend on the form of arsenic present. Arsenic comes in two main forms, trivalent and pentavalent, and the right treatment differs between them. Oxidation filtration handles the trivalent form by converting it first. Reverse osmosis systems remove both forms effectively at the point of use. Whole-home arsenic-specific filter media is another option for higher-demand situations.
Before we recommend any treatment system, we test. Putting in the wrong treatment for the wrong arsenic form costs money without solving the problem. That is the diagnose-before-replace rule applied to water quality: check the water, read the results, match the treatment to what the test actually shows.
What a full well water test covers
Most new-well tests in our area include coliform bacteria, nitrates, pH, hardness, iron, manganese, and total dissolved solids. Arsenic testing is usually a separate add-on that requires a lab equipped for heavy metals analysis. Our guide to reading a Texas well water report walks through the whole sheet line by line.
If you are on a private well and have not tested in three or more years, it is time. If there has been agricultural activity nearby, a new septic installation in the area, flooding that reached your well, or any change in how your water tastes, smells, or looks, test sooner. We have a full guide on how often to test your well water that breaks down a schedule based on your situation.
Getting the test done correctly
Certified labs and county cooperative extension offices process well water samples. The collection process matters more than most people realize. Coliform samples require a sterile container, a first-draw protocol, meaning you collect from the cold-water kitchen tap without flushing first and without touching the inside of the container or the faucet opening, and delivery to the lab within about 24 hours of collection.
Get the lab's specific instructions before you collect. A sample collected incorrectly can produce a false positive, or miss a real problem. We handle water testing for our service customers and can walk you through what your results mean. If you have already got results in hand and are not sure what to do with them, call us.
We go through the numbers, explain what matters, and recommend treatment only for what the water actually needs. If the water is not right, nothing else on the land works, and knowing exactly what is in it is the only way to fix it correctly.