Private wells are not routinely monitored like public water systems. The well owner is responsible for arranging appropriate testing, maintaining the well and responding to problems.
A sensible annual baseline
The U.S. Centers for Disease Control and Prevention recommends testing at least annually for total coliform bacteria, nitrates, total dissolved solids and pH. Local geology and land use may make other tests important. Your state or local health department is the best starting point for location-specific advice.
When to test promptly
- After flooding or suspected surface-water entry
- After repairing or replacing part of the well system
- When taste, odor, color or clarity changes
- When nearby spills, construction or land use create a new concern
- When someone in the household is pregnant or an infant begins using the water
- When neighbors identify a groundwater problem
Certified laboratory versus home screening
Home kits may help with preliminary screening or routine operational checks, but results used to make health and treatment decisions should come from a state-certified drinking-water laboratory. Sampling instructions matter: the container, faucet location, flushing time, preservation and delivery schedule can all affect a result.
Questions to ask the laboratory
- Are you certified by my state for the analytes I need?
- Which contaminants are locally relevant?
- Do you supply sterile or preserved containers?
- Where should each sample be collected?
- How quickly must the sample reach the laboratory?
- Will the report compare results with applicable standards or guidance?
Keep a well-water record
Save laboratory reports, inspection notes, treatment settings, maintenance dates and changes in water quality. Trends across several years are often more informative than a single isolated result.