# Well water testing

> What to test for on a private well, how often, what a lab panel costs, and how to take a sample that produces a usable result.

Canonical: https://watertreatmentpro.com/well-water-testing/

Last updated: 2026-11-09

Private well water has no utility testing it and no annual report. Testing is the owner's job, and the schedule is simple: bacteria and nitrate annually, a broader panel every three to five years, and a retest whenever the water changes. A lab panel costs $40 to $150.

## What to Test For

The core panel covers the parameters that drive both health decisions and equipment selection.

| Parameter | Why it matters | Typical limit |
|---|---|---|
| Total coliform and E. coli | Microbial contamination | Absent |
| Nitrate | Surface water influence, agriculture | 10 mg/L |
| Hardness | Softener sizing | 7 GPG action level |
| Iron | Staining, softener fouling | 2 - 3 ppm |
| Manganese | Staining, taste | 0.05 mg/L aesthetic |
| pH | Corrosion or scaling | 6.5 - 8.5 |
| Arsenic | Regional geology | 10 µg/L |

Add lead if the plumbing is older or the service line is unknown. Add uranium and radon in regions where they occur. Add PFAS if the well is near a manufacturing site, an airport, or a fire training area.

The point of the panel is not to collect numbers. It is to decide what equipment, if any, is needed. Hardness above 7 GPG means a softener. Iron above 2 to 3 ppm means an iron filter before the softener. Nitrate near 10 mg/L means reverse osmosis at the tap.

## How Often

Annually for bacteria and nitrate is the minimum. Those two change fastest and matter most for health.

Every three to five years, run the full panel. Hardness and iron shift slowly, but they do shift, and equipment sized on a ten-year-old test may be wrong.

Retest immediately if:

- The water changes colour, smell, or taste
- After heavy rain or flooding
- After any work on the well, pump, or pressure tank
- After a shock chlorination
- If a neighbour's well tests positive for something

## Taking a Sample That Works

A bad sample produces a bad result, and the most common bad result is a false bacteria positive caused by touching the inside of the cap or the spout.

1. **Get the bottle from the lab** and check the date on the preservative.
2. **Remove the aerator** from the tap.
3. **Disinfect the spout** with a flame or an alcohol wipe.
4. **Run the water** for five to ten minutes to clear the line.
5. **Fill to the line** without touching the inside of the cap or bottle neck.
6. **Refrigerate** and deliver within the lab's window, usually 24 to 48 hours.

For bacteria, do not sample from a filtered tap. You want the water as it arrives from the well, not after carbon.

## What It Costs

| Test | Cost | Turnaround |
|---|---|---|
| Bacteria only | $20 - $45 | 2 - 5 days |
| Bacteria and nitrate | $40 - $80 | 3 - 7 days |
| Full panel | $100 - $150 | 5 - 10 days |
| Arsenic or lead add-on | $25 - $60 each | 5 - 10 days |
| PFAS panel | $200 - $400 | 2 - 4 weeks |

Those are typical US lab prices. State health departments sometimes offer subsidized kits, and some counties run free bacteria testing for private well owners.

## Home Kits vs a Lab

A $15 test strip is useful for a quick hardness check before buying a softener. It is not useful for bacteria or nitrate.

| Method | Good for | Not good for |
|---|---|---|
| Test strips | Hardness, pH screening | Bacteria, nitrate accuracy |
| Handheld TDS meter | Total dissolved solids trend | Identifying what the solids are |
| Titration kit | Hardness | Anything health-related |
| Certified lab | All regulated parameters | Nothing, except speed |

The reason is sensitivity and specificity. A strip that changes colour in the presence of nitrate cannot distinguish 4 mg/L from 12 mg/L reliably, and 12 mg/L is the level that matters. A lab uses a calibrated instrument and reports a number.

For a household on a well with an infant, a pregnant person, or anyone immunocompromised, the lab panel is not optional. For a household that just wants to know whether a softener is worth buying, a hardness kit is enough to start.

## Reading the Result

The lab reports each parameter with a value and a limit. Two things matter: whether the value is above the limit, and whether it has changed since the last test.

A bacteria result of "absent" is what you want. A positive total coliform result means treatment or investigation, and a positive E. coli result means do not drink the water until it is resolved.

Nitrate at 8 mg/L is under the 10 mg/L limit and close enough to be worth watching, particularly with an infant in the house.

Hardness at 180 mg/L as calcium carbonate is 180 ÷ 17.1 = 10.5 GPG, which is very hard. That conversion is the one people most often get wrong. [How to read a water test report](https://watertreatmentpro.com/how-to-read-a-water-test-report/) covers the rest.

## Five Steps After a Positive Result

1. **Stop drinking the water** if bacteria or E. coli is present.
2. **Shock chlorinate** the well and lines, then retest after a week.
3. **Inspect the casing and grout** if the problem returns.
4. **Match treatment to the finding**, not to the symptom.
5. **Retest on schedule** so the trend is visible.

## Equipment Follows the Test

The order of decisions is test, then treat, then retest. A household that buys a softener before testing often finds the real problem was iron, or that the water was not hard at all.

The staging for a full system is in [well water system layout](https://watertreatmentpro.com/well-water-system-layout/), and the cost of the resulting equipment is in [well water treatment cost](https://watertreatmentpro.com/well-water-treatment-cost/). If you need a lab locally, [well water testing near me](https://watertreatmentpro.com/well-water-testing-near-me/) covers how to find one.