Your drinking water quality
Water quality
We keep a constant eye on the quality of the water that comes out of your tap to ensure it is safe and of high quality. Drinking water affects the health and well-being of us all, and this is why we leave nothing to chance.
There are around 120 sampling points in Tallinn and Harju County. These include kindergartens, schools, homes, and businesses, all scattered throughout the service area to ensure a complete overview of water quality in every district of the city.
All test results are publicly available on the Health Board's information system. On our website, we publish the test results of drinking water leaving the treatment plant.
What do we test water for?
By testing water, we can obtain information about its key parameters, which determine the safety and taste characteristics of drinking water.
Our test results provide information on both the chemical and microbiological characteristics of water, as well as physical properties such as colour, turbidity, temperature.
You can find information here on the water's hardness, pH level and bacteriological composition, as well as its compliance with drinking water quality standards.
Water hardness
The water hardness indicates the amount of dissolved calcium and magnesium in the water. There is no limit for the hardness of drinking water.
Hard water is not harmful to health, but it can have an impact:
- on the formation of scale,
- on the amount of soap and detergents you use,
- the lifespan of household appliances.
The hardness of the drinking water leaving the treatment plant varies seasonally, depending on the water in Lake Ülemiste. In winter and spring, the water is harder, up to 2.5 mmol/l. In summer and autumn, the hardness indicator is lower, starting at 1.8 mmol/l.
Veekareduse näitajad
0…0,5 mmol/l
Soft
0,5…1 mmol/l
Moderately soft
1…1,5 mmol/l
Slightly hard
1,5…2 mmol/l
Moderately hard
2…3 mmol/l
Hard
> 3 mmol/l
Very hard
Chlorine
A small amount of chlorine is added to drinking water at the water treatment plant before it is pumped into the distribution network. This ensures that the water remains clean and fresh throughout its long journey to consumer's taps.
The amount of residual chlorine in drinking water is strictly regulated:
- up to 1 mg/l in the water leaving the treatment plant,
- up to 0.5 mg/l at the consumer’s tap.
If you have more sensitive taste buds, you may sometimes notice a smell or taste of chlorine, but this is not a bad thing – on the contrary, it just shows that the water is safe.
Recommendation
If the chlorine smell seems strong, pour the water into a jar and leave it to stand for a while. Chlorine evaporates when it comes into contact with oxygen.
Lead
The public water mains in Tallinn are made of modern and safe materials, such as plastic, steel or cast iron.
The use of lead as a material for water pipes ended at the beginning of the 20th century. Until then, it was only used for house connections alongside steel and cast iron. The vast majority of buildings and pipes in Tallinn were built much later, when lead was no longer used as a material for house connections.
Unfortunately, we lack precise information on the materials used for old house connections installed before the early 20th century, and these materials are often only revealed during excavations. If, while working to fix a water incident, we identify that a lead pipe has been used in the house connection, we will replace that section with a water pipe made of a modern material.
However, a number of sampling exercises have shown that the lead limit in the water can only be exceeded if the water is left sitting in the pipes for a long period of time, i.e. if it is not used.
Coliform bacteria
The presence of isolated coliform bacteria in drinking water is an indication that the water has been sitting in the pipes for a while.
This is an indicator parameter and drinking such water does not usually cause malaise in a person with normal immunity.
However, if coliform bacteria are found in tap water, we recommend boiling it before drinking or temporarily using bottled water to eliminate any risk.
Read the recommendations from the Health Board.
How to improve your water quality?
Flushing by letting the water run is an effective way to improve water quality because it speeds up the replacement of water in the pipes.
To this end, we also recommend leaving taps open for short periods at remote points of consumption on the network.
You should also check the water metering unit on your property. If you have installed filters, they will certainly need to be maintained or replaced periodically.
Which minerals can you find in drinking water?
The daily requirement and concentration of minerals in drinking water leaving the treatment plant.
Laboratory tests on tap water in Tallinn show that drinking two litres of water a day covers:
- 13% of your daily calcium need,
- 5.2% of your magnesium need,
- 1.1% of your sodium need.
| Parameter | Average concentration in drinking water | Average amount in 2 l of drinking water | Average daily intake recommendations | % of daily need |
|---|---|---|---|---|
| ParameterPotassium, K | Average concentration in drinking water2.5 mg/l | Average amount in 2 l of drinking water5.0 mg | Average daily intake recommendations3500 mg | % of daily need 0.1% |
| ParameterCalcium, Ca | Average concentration in drinking water67 mg/l | Average amount in 2 l of drinking water134 mg | Average daily intake recommendations1000 mg | % of daily need 13% |
| ParameterMagnesium, Mg | Average concentration in drinking water8 mg/l | Average amount in 2 l of drinking water16 mg | Average daily intake recommendations300 mg | % of daily need 5.3% |
| ParameterSodium, Na | Average concentration in drinking water8.5 mg/l | Average amount in 2 l of drinking water17 mg | Average daily intake recommendations1500 mg | % of daily need 1.1% |
| ParameterManganese, Mn | Average concentration in drinking water0.005 mg/l | Average amount in 2 l of drinking water0.010 mg | Average daily intake recommendations3 mg | % of daily need 0.3% |
What water quality concerns do people come to us with?
In 2024, 178 consumers contacted us about the quality of their drinking water. The enquiries were mainly about the smell of chlorine or the turbidity of the water.
Cloudy water
Following maintenance work on the water pipes, the tap water may be temporarily cloudier than usual. The turbidity is caused by sediment starting to move in the pipes, which is a common phenomenon after a water main has been flushed or repaired. The turbidity will disappear after a short flushing. Once the work is finished, the local mains are flushed thoroughly and the water is tested for turbidity.
Smell and taste of chlorine
In autumn, when the water temperature drops, the smell of chlorine may become a bit more distinctive. This is because chlorine stays longer in cold water. Chlorination is a widely used preventive method in drinking water treatment that helps to maintain microbiological quality in the water distribution network.
We regularly measure the levels of chlorine in different parts of the city, and the residual chlorine levels usually remain between 0.05–0.5 mg/l. In 2024, all chlorine measurements also fell within the limits set for drinking water.
