A test only helps if you can read it
A lab report can look like a page of chemistry homework. Most of it comes down to a few lines: is there bacteria, are nitrates and lead where they should be, and what is the water doing to your pipes. This guide walks through each one in plain English. If you have not tested yet, start with our well water testing service, which covers when to test and how we take the sample.
Bacteria: present or absent
Bacteria results usually read “present” or “absent” rather than a number.
- Total coliform absent. Good news. Nothing on this test suggests surface water is getting into the well.
- Total coliform present, E. coli absent. A warning sign. Something is letting surface water or soil into the system, often a loose cap, a cracked casing or recent well work. It is not proof the water will make you sick, but it needs a closer look.
- E. coli present. Do not drink the water or cook with it until the problem is fixed and a retest comes back clean. Use bottled water in the meantime.
A positive result usually means finding the way in first, often with a casing repair or sanitary cap, and then deciding whether UV disinfection makes sense. Retest after any fix.
Nitrates and lead
Nitrates
Nitrates come from fertilizer, septic systems and livestock, so they show up more on farm ground and older lots. The EPA drinking water limit is 10 milligrams per liter, measured as nitrogen. Results near or above that deserve attention, especially with a baby in the house, because infants are the most sensitive. Boiling does not remove nitrates. It concentrates them.
Lead
Lead in well water almost always comes from the pipes and fittings in the house, not the ground: older copper with lead solder, brass fittings or fixtures. The EPA says there is no known safe level of lead in drinking water, so any detectable lead is worth talking through. Acidic water makes lead more likely to show up, which is why lead and pH belong on the same test.
pH
pH tells you whether the water is acidic or alkaline. The EPA’s recommended range for drinking water is 6.5 to 8.5. Below that, water tends to eat at copper and brass, leaving blue-green stains in sinks and tubs and pinhole leaks over time. An acid neutralizer is the usual fix, and you can read more about water treatment options.
Hardness and iron
Hardness is minerals, mostly calcium and magnesium. It is not a health problem, but it leaves scale on fixtures and in water heaters. The USGS scale calls water above 120 milligrams per liter hard and above 180 very hard. Iron leaves orange or rust stains, and the EPA’s taste and staining guideline is 0.3 milligrams per liter. A softener or filter sized to your results handles both.
Prince William and Fauquier: different ground, different water
What comes out of your tap depends on the rock your well is drilled into, and that changes across our area. These are general patterns, not rules. Your neighbor’s water can be quite different from yours.
Prince William County
Parts of Prince William sit on red shale and sandstone. There, hardness, iron and a sulfur (rotten egg) smell are the common complaints, so those lines on your report are the ones to watch. In Bristow, hardness and sulfur smell questions come up a lot. If yours smells like eggs, see why well water smells like rotten eggs. More on the county at our Prince William County page.
Fauquier County
Much of western Fauquier sits on harder crystalline rock, where low pH water shows up more often, and with it blue-green stains on copper and fixtures. Around Warrenton, pH and acid neutralizer questions are common, and around Bealeton, iron and hardness. See our Fauquier County page for more.
What to do with your results
If everything is in range, keep the report with your house papers and plan to test bacteria again next year. If something is off, do not buy equipment off a single number. Call 703-791-3981 and we will go over the report with you, explain the options without pressure, and retest after any fix so you know it worked.