Lahti Aqua

Fresh groundwater is filtered by the gravel ridges of Salpausselkä every day of the year. In Lahti, we drink the best groundwater in the world.


The regional water supply company owned by the city of Lahti provides water supply services to 145,000 inhabitants and companies in Lahti and Hollola and has more than 100 years of experience. The water services include customer service, sourcing and distribution, wastewater management and treatment.

Only groundwater is supplied to customers, which is quite unique in urban conditions. More water is formed in the Lahti region than is consumed in the area, about 100,000 m3 per day. So there is enough water and you can enjoy it without any worries.

Get to know this Lahti Group company, which takes care of the area’s drinking water and wastewater treatment.

Lahti Aqua homepage

Environment first

The annual leakage rate of the water supply network in Lahti was 6.8% (national average 17%). The low leakage of the network means an annual saving in electricity use of about 600 MWh and at the same time a smaller carbon footprint and participation in work to combat climate change.

Solar energy and biogas recovery

The solar energy panels placed on the roofs of the treatment plants produce 150 MWh of electricity per year for their own needs. The heating energy used in the treatment plants is biogas from sludge digestion, and any surplus energy is fed into the city’s district heating network for residents to use.

Visits to Lahti Aqua

During the visit, water supply activities will be presented in general in the visitor center. Lahti Aqua treatment plants are not open for  any visits.

Visiting instructions and accessibility
The Lahti Aqua visitor centre is located on the office premises in the harbour area near Sibeliushall. The parking area is in front of the visitor centre, Satamakatu 5 Lahti. There is a ramp to the visitor centre and it is accessible by wheelchair.

Send a visit request

Did you know this about Lahti Aqua?

  • 01
    The first water intake plant in Lahti opened in 1909 and wastewater treatment began in 1910.
  • 02
    We monitor the quality of domestic water by more than 1,000 samples annually.
  • 03
    The largest users of clean water in the area are Hartwall, which is one of the largest beverage companies in Finland, and Fazer, which is one of the largest bakeries in Finland.
  • 04
    In Lahti, residents use an average of 120 litres per day of clean water.
  • 05
    There is a total of 2,115 km of water supply network in Lahti.

Water protection in Lake Vesijärvi Foundation

The Vesijärvi Foundation has done long-term work in the rehabilitation of Lake Vesijärvi. Decades of work have produced excellent results. The work of the foundation has been possible through the cooperation of municipalities, companies and individuals. The foundation also cooperates with Lahti Aqua Oy, which has an obligation to monitor the impact of the dilution water intake on Lake Vesijärvi.

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Pure groundwater is the raw material of Teerenpeli whiskey

In November 2020, Teerenpeli Brewery & Distillery from Lahti won the “Worldwide Whiskey Producer” series in the world’s largest alcohol competition, the International Wine and Spirit Competition. The IWSC victory puts Finnish whiskey on the world map. Teerenpeli restaurants serve the products of their own brewery and distillery and are also utilized in the restaurant’s food products. Local clean groundwater filtered by Salpausselkä and local grain serve as raw materials for award-winning drinks.

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