Tap water in Sweden: why residual chlorine stays in the network

8 treatment steps lie between Lake Mälaren and the network at the Görvälnverket. Norrvatten describes the plant as follows:

• A band screen holds back fish, algae and coarse suspended matter.
• Aluminium sulphate starts the flocculation of humic substances, clay particles and microorganisms; a small amount of sodium silicate enlarges the flocs.
• The flocs sink to the bottom or are lifted to the surface with air bubbles and skimmed off.
• A sand filter 1.5 metres high removes the last flocs.
• A biofilter made of activated carbon, 2.5 metres high, reduces substances that impair smell and taste.
• Ultraviolet light disinfects the water in dedicated reactors.
• Lime water raises the pH value slightly into the alkaline range, thereby slowing corrosion in the pipe network.
• At the outlet, a very low dose of monochloramine is added to slow bacterial growth in the network.

The fifth stage is remarkable. In Sweden, activated carbon is used at the waterworks long before it makes its way into a kitchen. More on this in the guide to the activated carbon filter for water.

Stockholm Vatten och Avfall keeps 0.3 milligrams per litre of active chlorine in the outgoing water in the warm season and 0.2 milligrams per litre in the cold season. The source is monochloramine, a mild chlorine compound. The figure appears as a footnote in both reports for 2025. Travellers can taste the difference. If you arrive in July, you get a higher dose than in February.

In Sweden, the limit value for total active chlorine is 0.40 milligrams per litre in outgoing drinking water. Norsborg and Lovö each reported 0.25 milligrams per litre for 2025. The residual breaks down further on its way to the tap. In north-western Stockholm, the annual value was 0.11 milligrams per litre, and in the south and in Huddinge 0.07.

This clearly sets Sweden apart from its neighbours. Norway relies on ultraviolet light and largely does without residual chlorine, while Denmark usually does without disinfection of its groundwater altogether. Sweden combines both: irradiation at the plant and a chloramine to protect the water on its way. Taste and filtration are explained in the article on chlorine in drinking water.

Since 1 January 2026, a limit of 4.0 nanograms per litre has applied in Sweden to the sum of four per- and polyfluoroalkyl substances (PFAS). In the regulation, the parameter is called PFAS 4. For an extended sum of 21 substances, known as PFAS 21, a limit of 100 nanograms per litre applies. Both values are set out in the Swedish drinking water regulation (LIVSFS 2022:12). In doing so, the food authority Livsmedelsverket follows a guideline value issued by the European Food Safety Authority in 2020.

The stricter value hits Lake Mälaren at a sore spot. Norrvatten itself writes that the levels in the raw water are close to the new limit. The finished drinking water from the Görvälnverket complies with it because the carbon stage already binds part of the substances. A new plant with additional treatment is due to go into operation in 2035. Four of the six groundwater reserve plants show fluctuating levels, some of them above the new limit.

Stockholm's values for 2025 are below it, but only by a small margin: Norsborg reported 2.5 nanograms per litre in the finished drinking water, Lovö 3.1. At the tap, the supplier measured 3.1 nanograms per litre in the north-west and 2.6 in the south. For the situation in Germany, the guide to per- and polyfluorinated chemicals puts this group into context.

Stockholm Vatten och Avfall takes 6,500 water samples a year, from Lake Mälaren through the plants and the network to the customers. The reports dated 30 March 2026 show what treatment changes in the raw water.

At the Norsborg waterworks, the number of coliform bacteria fell from 165 per 100 millilitres in the raw water to below 1 in the finished drinking water. Escherichia coli and intestinal enterococci in the drinking water were also below 1 per 100 millilitres. The colour fell from 28 to 5.5 milligrams of platinum per litre, and the turbidity from 1.7 to 0.05 units. Organically bound carbon, a measure of humic substances from the forest, fell from 9.0 to 4.1 milligrams per litre. All the figures given are annual averages.

The other parameters remained well below their limits. Nitrate in the drinking water was 0.88 milligrams per litre against a permitted 50, fluoride below 0.20 against 1.5. Plant protection products remained below the limit of quantification. The regulation allows 0.10 micrograms per litre of them for each individual substance and 0.50 in total.

The colour answers a question that is often asked in summer. Raw water in Sweden looks brownish because it carries humic substances from bogs and forests. Most of this disappears at the waterworks. For 2024, the supplier recorded 159 complaints about discolouration and 35 about an unusual smell or taste.

The copper level at the tap is 80 times higher than at the waterworks. In 2025, an average of 0.00079 milligrams per litre left the Lovö plant for the network, while 0.062 reached users in north-western Stockholm. The south side followed the same pattern: Norsborg supplied 0.0016 milligrams per litre, and at the tap in southern Stockholm and Huddinge it was 0.13.

Nickel follows the same pattern on a smaller scale. Lovö released 1.4 micrograms per litre, and at the tap in the north-west it was 4.7. Norsborg supplied 1.8, and 6.3 arrived in the south. Over the same route, cadmium rose from 0.0092 to 0.029 micrograms per litre and iron from 1.0 to 25.

Copper and nickel remain well below the limits. At 0.13 milligrams per litre, copper uses up just over 6% of the permitted value. At 6.3 micrograms per litre, nickel reaches about a third of 20. Even so, the increase comes from the same source as in Germany: the pipes inside the building.

Two caveats apply. The sample is small: 36 samples out of 883 flushed samples taken in 2025. And they were flushed samples. Stagnant water that has stood in the pipes overnight carries higher levels.

On 1 January 2026, lead was given a limit of 5.0 micrograms per litre in Sweden; previously it was twice that. In Germany, the old value of 0.010 milligrams per litre still applies until the end of 11 January 2028. Sweden is therefore introducing the stricter limit two years earlier. Stockholm's readings at the tap are 0.23 micrograms per litre in the north-west and 0.42 in the south, i.e. far below it.

Stockholm Vatten och Avfall gives the city's water hardness as 4 to 6 degrees of German hardness. The 2025 annual figures confirm this. Norsborg supplied water at 4.4 degrees, Lovö at 5.7, and at the tap it was 5.3 in the south and 5.6 in the north-west.

The regulation itself has a peculiarity. Hardness as such is not regulated in Sweden. Instead, its two components are regulated as indicator parameters: calcium at 100 and magnesium at 30 milligrams per litre. One degree of German hardness corresponds to 7.1 milligrams of calcium or 4.3 milligrams of magnesium per litre. For travellers, soft water means one thing above all: the kettle in the holiday flat stays free of limescale.

Just over 1 million permanent residents of Sweden get their drinking water from their own well. Among the occupants of holiday homes, the figure is roughly the same. Both figures come from the Geological Survey of Sweden. Holiday homes are therefore often connected to a system outside municipal control. Private wells fall outside the regulation. Their owners have them tested voluntarily.

Campsites, on the other hand, are covered without exception. Livsmedelsverket makes it clear: water from a business or a public body always falls under the regulation. The usual threshold of 10 cubic metres per day or 50 people supplied does not apply here. The authority explicitly names campsites and the letting of accommodation with its own water supply as examples.

This distinction has a practical impact on your holiday. The tap at the campsite is subject to the same rules as the one in a Stockholm flat. The tap in a rented holiday home by a lake, on the other hand, may be connected to a well whose last analysis was years ago. Ask the landlord for the date of the last water analysis.

If you travel by motorhome, you have a third problem: your own tank. The guide to water treatment in a motorhome offers advice.

There are 3 reliable ways to get drinking water on the road in Sweden. As a rule, all three are covered by the drinking water regulation:

• The tap at the campsite, because it is subject to the drinking water regulation.
• Signposted water points at harbours and rest areas. Look out for the word dricksvatten. If the sign says ej dricksvatten, it is non-drinking water.
• Restaurants and cafés. Tap water is called kranvatten in Swedish and is usually served free of charge with meals.

The association Svenskt Vatten even has its own seal for restaurants and workplaces. Those that do without bottled water and serve tap water may call themselves Kranmärkt. In 2025, eighty municipalities took part in the Swedish competition for the best tap water; Älvsbyn won ahead of Vindeln and Jönköping.

One rule applies everywhere: in Sweden, only cold water is classified as a foodstuff and monitored. Hot water from the same tap is considered non-drinking water in Sweden. Always use the cold side for drinking and cooking. For refilling, the guide Filling up with water on the road in a motorhome will help.

In Gothenburg, Malmö and Jönköping, tap water from the municipal network is subject to the same regulation as in Stockholm. All 1,750 municipal waterworks report exceedances to the competent authority. The monitoring obligation depends on the plant, not on the size of the town.

However, only some of the suppliers publish annual reports as detailed as Stockholm's. If you are looking for hard figures for a destination, the municipality is your best bet. The keyword to search for there is dricksvattenkvalitet, Swedish for drinking water quality. Since 1 January 2026, suppliers have had to test their raw water according to fixed requirements.

There is still no nationwide database with readings for each municipality. Livsmedelsverket is only now setting up the reporting channels for it.

3 situations on a holiday in Sweden call for a water filter; in all other cases, the tap is enough. In a hotel in Stockholm or a flat connected to the municipal network, measurements show that the water is clean, so a filter adds little there.

A filter is worthwhile in three cases:

• Holiday home with its own well. The system is not subject to mandatory monitoring, and the last test result may be old.
• Motorhome with its own tank. Days often pass between filling and drinking. Germs multiply in a warm tank.
• Sensitive palate. In summer, residual chlorine is 0.3 milligrams per litre at the waterworks outlet. Activated carbon reliably binds such compounds.

Alb Filter makes activated carbon filters for the kitchen and for travel. They work on the same principle as the carbon stage at the Görvälnverket, just on a much smaller scale. For metals from the pipes in the building, a simple step helps in everyday life: let the water run until it feels noticeably cooler, and only then drink it.