CEBEDEAU • Industrial Wastewater Tax Reform Q&A

Adaptation, reforms… It is not always easy to grasp all the implications of these changes within your company. We help you see things more clearly.

The principle?

Taxation on wastewater is based on the “polluter pays” principle. This pillar of European Union environmental policy requires companies to bear the costs associated with the pollution they generate, including prevention, control, and elimination measures, as well as the impacts on society.

The amount of the tax on industrial discharges is directly linked to the pollutant loads discharged for several parameters (flow rate, suspended solids, COD, nitrogen, phosphorus, metals, and ecotoxicity), expressed in “pollutant load units” (PLU) based on a calculation formula defined by the Water Code (Art. D.262). The amount of tax due per PLU is revised annually, in accordance with Article D.330-1 of the Water Code. Thus, the amount due per PLU has increased from EUR 13 (2015 financial year) to EUR 17.32 (2025 financial year), representing an average increase of around 3% per year.

Reforms

In 2018, the Walloon Government required establishments discharging industrial wastewater into public treatment plants to enter into a service contract with the SPGE (Société Publique de Gestion des Eaux) and the OAA (Organismes d’Assainissement Agréés) for the treatment of this wastewater.

The CVAI (Coût-Vérité Assainissement Industriel, or true cost of industrial wastewater treatment) associated with this service is calculated by taking into account the share of investment costs (CAPEX) and operating costs (OPEX) of the infrastructure associated with industrial wastewater. It therefore represents the real (“true”) cost of collecting and treating industrial wastewater.

Industrial companies that discharge their effluents into public infrastructure are required to pay the annual CAI (Coût Assainissement Industriel, or Industrial Wastewater Treatment Cost), which is the lesser of the CVAI and the tax (UCP).

At the end of 2025, in its budget agreement, the Walloon Government planned a 47% increase in the value of the UCP in 2026, i.e., €25.48/UCP.

How will this affect your costs?

If you discharge your effluent into surface water (Company A): the tax applies and, for the same level of pollution, your associated costs increase by 47%.

If you discharge your effluent into the public sewer system and your CVAI is and remains lower than the tax (in other words, CAI = CVAI) (Company B): no impact. (Except for the annual change in the operating costs of public treatment plants).

If you discharge your effluent into a public sewer and your CVAI is higher than the tax (in other words, CAI = tax): for the same level of pollution, your associated costs could increase by up to 47% (the actual increase will depend on the relative values of CVAI and tax according to the new pricing structure – Companies C and D).

CEBEDEAU's EASYTAX service provides you with an annual forecast of the amount due.

[1] 17,32 €/UCP

[2] 25,48 €/UCP