Global Daily Tax News, Denmark To Broaden Tax On Wastewater Overflows, (Jan 5, 2026)

The Danish Government has decided to introduce a tax on untreated wastewater from 2027 and postponed the phasing in of the lime tax until 2030.

During downpours, the capacity of the sewer system and treatment plants can be exceeded. The excess water – consisting of a mixture of rainwater and untreated wastewater – is discharged directly into the aquatic environment, known as "overflows". Untreated wastewater typically contains high concentrations of nutrients, such as nitrogen and phosphorus, which in large quantities have a harmful effect on the aquatic environment.

Denmark presently levies a tax on the discharge of treated wastewater, but not on the discharge of untreated wastewater from overflows. The new tax on the discharge of untreated wastewater from 2027 is intended to remedy this.

"When it rains heavily, we too often see untreated wastewater flowing into our water environment," said Denmark's Minister of Taxation, Ane Halsboe-Jorgensen. "This is neither reasonable nor sustainable. With the new tax, we are making it clear to the wastewater companies that they must prevent overflows to a much greater extent, and that overflows should be a last resort. We must ensure a clean water environment for the next generation, and this tax is another step in that direction."

The tax will correspond to the existing tax on treated wastewater and thus reflect the discharge of nitrogen, phosphorus, and organic matter to the aquatic environment. Planned overflows as a result of renovation or emergency overflows as a result of accidents in the wastewater system will also be covered by the tax on overflows. The tax on piped water will be reduced from 2029, which will counteract the impact on water consumers.

The parties to the agreement have also decided to postpone the planned phasing-in of the carbon tax on agricultural lime from 2028 to 2030. It is planned that the tax will be DKK750 per ton of CO2 in 2030 as already agreed.

The Government said, "The postponement is due to administrative challenges with the implementation of the tax, and uncertainty about the CO2 effects of spreading lime on fields and therefore also the effects of a tax. The CO2 effects are expected to be clarified in more detail in 2028. The government and the parties to the agreement will then decide on the further process for the tax."