Well water

Taking a water sample

You can take a water sample from your well yourself. Getting a sample tested in a laboratory costs around 110 € – 350 € depending on the scope of the analysis.

A conventional water sample is taken by running the tap for at least 5 minutes, after which the vials are filled with water. Do not touch the mouth or the inside of the vial.

Delivering the sample

The water sample must be delivered to the laboratory on the same day it was taken. You will receive the test results by post in approximately 2 weeks. You should discuss the need for different analysis with a health inspector or the laboratory in advance.

It is recommended to test water from drilled wells for arsenic, radon, and fluoride, in addition to the usual suspects. A water sample should be taken every 3 years.

The nearest laboratory that tests water samples:

KVVY Tutkimus Oy, Patamäenkatu 24, Tampere.

The laboratory accepts samples Monday-Thursday 8-16, and on Fridays 8-14. You can order vials for samples from the laboratory to be delivered to your home. Additional information.

Repairing ring wells

Empty the well with a powerful pump. Clean the water hoses, pump, ladder, and other parts going down the well thoroughly before use.
Clean the well by scrubbing the inside thoroughly on a ladder with, for example, a coarse brush. Use water to scrub each ring from the top to bottom. Do not use cleaning detergents.
Seal any cracks, seams, or gaps in the concrete rings using cement mortar or a special food safe sealant sold in hardware stores. It is especially important to check and seal the water pipe ducting. If the concrete rings have moved out of place, they must be installed back into place. You can also install foam sealing into the seams of the rings and in between the top ring and the lid.
Remove the sludge from the bottom of the well and pour a 20cm layer of washed and rust-free sand or gravel to the bottom. You can also mix clean, crushed limestone into the sand/gravel. The pump’s suction pipe should be at least 30cm from the bottom.
Let the well fill up and run the water until it runs clear. You must disinfect the well before the water is safe to drink (instructions below).

Disinfecting your well

You can effectively disinfect your well using chemicals such as hydrogen peroxide, sodium hypochlorite, or calcium hypochlorite. It is recommended to use hydrogen peroxide, as it is the safest option. You can buy these chemicals at pharmacies. Use them with caution and according to instructions.

The disinfectant is administered as follows:

10% sodium hypochlorite approx. 2,5 desiliters/cubic meter of well water
70% calcium hypochlorite approx. 300 grams/cubic meter of well water
10% hydrogen peroxide approx. 3 litres/cubic meter of well water
The formula for calculating the cubic meter (m3) of water: r x r x h x 3,14
r = half of the cement ring’s diameter in meters
h = height of the water measured from the bottom in meters

Dilute the disinfectant into water and pour it down the walls of the cement rings into the well. You could use, for example, a clean watering can to do this. You can also disinfect the water pipes by opening the taps for a short while.
Leave the disinfectant in the well for at least 24 h.
Empty the well as many times as it takes for the smell and taste of chlorine to disappear.

You do not necessarily need to empty your well when using hydrogen peroxide, as it disintegrates in two days. Just run your taps after the two days, and the water is safe to use.

It is recommended to wait at least 7 days after disinfecting before taking a water sample.

Private wells

Private households who are not catered to by a water supply agency get their drinking water from drilled wells or driven wells

Driven wells (ring wells)

Driven wells, or ring wells, are only a few meters deep and are lined with concrete rings. The oldest wells are lined with stones.

The water quality of shallow wells may be compromised if surface water gets in, as it brings bacteria into the well. Surface water can cause well water to become cloudy during spring and autumn. The well water often has high iron concentrations. Wells near fertilized fields or manure storage may have high concentrations of nitrate, which makes the water unsafe to drink.

Drilled wells

Drilled wells are constructed by drilling into bedrock, sometimes as deep as 200 meters. In Pirkanmaa, risks to water quality include radon and arsenic. Individual wells can vary drastically, so the only way to know is by taking a water sample.

Water quality requirements and recommendations for private wells are ruled in the decree 401/2001 by the Ministry of Social Affairs and Health.

The structural condition of the well should be inspected annually and a water sample should be taken every three years, if no abnormalities appear in the taste, smell, or colour of the water. You can easily take the water sample yourself. Health inspectors provide guidance on well water samples and well repair. The owner of the well is responsible for paying the laboratory’s fee for testing water samples.

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