The laboratory usually supplies sample bottles. Depending on the type of test to be completed, the bottles may contain preservatives or include special instructions for handling the samples. Private water can most easily be sampled at the drinking water tap by carefully filling the bottles to avoid spilling or getting other contaminants into the bottle. For nitrates and other basic water tests, the bottles can usually be mailed to the laboratory. Some tests, such as those for coliform bacteria, may require that the sample bottles be kept cool until they are delivered to the laboratory for analysis.
Most laboratories mail back the sample results within days or several weeks.
The results typically indicate whether a particular contaminant was detected in the sample. If a contaminant is detected, the results will include the concentration of the contaminant and an indication of whether this concentration exceeds a drinking water quality standard. If a standard is exceeded in your sample, you should retest the water supply immediately and contact your public health department for assistance. Some problems can be handled quickly. For example, high bacteria concentrations can sometimes be controlled by disinfecting a well.