Lahti is partially located on a moraine ridge, which is an important area for recharging groundwater. Protecting groundwater is carefully considered in the city's master plan. Groundwater bodies under and close to the ridge are large both by surface area and volume. The water table is stable over the years and the quantitative status is good.
High-quality groundwater straight from the tap
Groundwater is naturally filtered and purified by the Salpausselkä gravel ridge system and distributed to local consumers by the city-owned company Lahti Aqua Ltd. that ensures its high-quality. The ridges filter the water so effectively that only minimal treatment is required. Lahti Aqua has upgraded the purification technology and in 2015 all collected samples complied with the quality standards of the Drinking Water Directive.