Home strips can give a quick screen for selected properties such as hardness or pH, while a certified laboratory can analyze bacteria, nitrate and metals using defined methods and report concentrations. Use the lab's sampling instructions for decisions about health-related contaminants, then use simpler tools for routine checks they are designed to measure. Read the well-water testing guide for annual tests and triggers.
A home kit is convenient for routine screening, but its result is only useful for the substances and ranges the kit actually measures. A certified lab is the better choice when treatment depends on a dependable result.
Side by side
| Home kit | Certified laboratory | |
|---|---|---|
| Typical use | Quick check of properties listed on the package | Bacteria, nitrate, metals and a broader test panel |
| Result | Color chart or digital reading | Report with measured concentration and method |
| Sampling | Follow the kit’s steps | Use the lab’s bottle and preservation instructions |
| Best next step | Repeat or confirm unexpected results | Match treatment to the report and retest when advised |
The CDC recommends annual private-well testing for total coliform bacteria, nitrate, total dissolved solids and pH and directs well owners to state-certified labs. See the CDC’s well-testing guidance.
Use the right result for the decision
Use a lab report before choosing treatment for health-related contaminants. Use a home kit only within its stated detection range and accuracy, and do not treat a negative screening result as proof that unmeasured contaminants are absent. For a private well, see our annual testing guide and water-filter certification guide.
Browse testing and parts.
Common questions
Can a home water test kit replace a certified lab?
Not for every contaminant. Choose a state-certified laboratory for bacteria, nitrate and metals when a reliable concentration is needed.
What can a test strip measure?
It depends on the kit. Read the included method and detection range; common strips screen selected properties such as hardness, pH or chlorine.
How should I collect a lab sample?
Use the lab's supplied bottle and exact sampling, preservation and delivery instructions. Do not sample through treatment equipment unless you are testing treated water.