The most reliable way to test the quality of well water is in the laboratory from a sample taken in accordance with the laboratory’s instructions. Microbiological and chemical variables are selected for the test based on the type of well and local risks. A quick test performed at home can only provide preliminary information on the parameters specified in the instructions for use, and it is not a substitute for a comprehensive household water study.
What does a well water study include?
A well water test is an analysis entity that determines the quality of well water by measuring several chemical and microbiological variables. The basic package usually includes the determination of coliform bacteria and E. coli, pH value, nitrate content, turbidity and colour. More extensive analyses also examine heavy metals, such as arsenic, lead and manganese, as well as other harmful substances.
Well water quality check can be divided into two main categories:
- Microbiological analysis: To determine whether the water contains bacteria or other microorganisms that pose a health hazard. This is the single most important area of study, as bacterial contamination can pose a serious health risk.
- Chemical analysis: Measures the concentrations of substances in the water, such as nitrate, iron, manganese, fluoride, and heavy metals. Chemical parameters affect both health and the usability of the water.
The scope of the study should be chosen as needed. In the case of a new well or problem situation, an extensive analysis provides the most comprehensive picture of the water quality. A more limited basic examination is often sufficient for regular monitoring.
How to take a well water sample correctly?
Ask the laboratory performing the test for sample containers and sampling instructions suitable for the selected specifications. The sampling point, preparation of the tap, running the water, filling the container, storage and transport may vary depending on the study. Deliver the sample to the laboratory within the time and temperature specified by the test.
How often should the well water be tested?
For private wells in Finland, Vesi.fi recommends a basic analysis every three years and a broader analysis every six years. Test sooner after commissioning a well, flooding, repairs or a change in the water’s smell, taste or appearance. Follow local guidance when testing wells elsewhere.
Well water testing is especially important in the following situations:
- a new well is commissioned
- the water’s taste, smell or colour changes
- excavation or construction occurs nearby
- there is flooding or exceptional rainfall
- the well is repaired or cleaned
- agriculture, fuel tanks or other possible contamination sources are nearby
A long break in use, for example at a well at a summer cottage after winter, is also a good reason to examine the water before regular use. Monitoring the quality of well water is a preventive activity that protects the health of the entire household.
What do the research results of well water tell us?
Results show the measured parameters in the sample, not every possible contaminant. In Finland, relevant results can be assessed against the applicable drinking-water requirements and recommendations. A water result does not diagnose illness in a person. Ask the laboratory or local environmental health authority about findings that need action.
Microbiological results
E. coli is an indicator of faecal contamination. Other coliform bacteria can also come from environmental sources, so the two findings should not be treated as identical. If contamination is suspected, obtain advice from the laboratory or local environmental health authority about safe water use, investigation of the cause, remedial work and repeat sampling.
Chemical results
Elevated nitrate can be associated with agricultural or wastewater contamination. Iron can affect taste, colour and deposits, while manganese and other contaminants require assessment of the measured concentration and health context. Findings above applicable limits or recommendations should be discussed with the laboratory or environmental health authority.
Where is the well water analysis performed and how much does it cost?
Choose a laboratory with appropriately accredited methods for the analyses requested. In Finland, local environmental health authorities can advise on suitable laboratories. Home water tests provide preliminary information within their stated intended use.
Ask the laboratory for a current quote covering:
- the microbiological and basic chemical parameters required
- any additional parameters justified by local risks or the well type
- sample containers, transport and any repeat sampling
Home testing and laboratory analysis differ in scope and purpose, so compare the measurements included rather than price alone.
Laboratory analysis is the most reliable way to ensure the quality of well water, and if necessary, the result should be verified with a follow-up examination suitable for the situation or by contacting the municipal environmental health authority. Rapid tests can support decision-making, for example, when you want to quickly assess the situation before taking a laboratory sample.
Read more about the selection of water tests. Use the home test only for the measurements specified in its user manual and confirm an abnormal or health-relevant result with a laboratory test.
