Separate sewerage in Hoeilaart improves water quality

New separate sewerage system discharges wastewater and rainwater separately, with a retention basin and improved overflow operation.

Generic image of separate pipes for wastewater and rainwater, with a water treatment plant and a watercourse in Flanders in the background.
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Generic image of separate pipes for wastewater and rainwater, with a water treatment plant and a watercourse in Flanders in the background.

The municipality of Hoeilaart has completed sewerage and road works, establishing a separate sewerage system for the separate discharge of wastewater and rainwater.

During the works, a separate sewerage system was installed. This means that wastewater and rainwater are discharged via separate pipes. The wastewater from homes and businesses goes to the wastewater treatment plant in Neerijse, where it is treated before the water flows back into nature. This prevents untreated wastewater from entering the watercourses.
The rainwater is discharged separately to the watercourse. A retention basin was also constructed for this purpose in the Rode Kruisstraat. During heavy rainfall, this basin can temporarily collect the rainwater and then discharge it more slowly into the IJse river, helping to reduce the risk of water nuisance.
The operation of the overflow in the Rode Kruisstraat was also improved. This allows less diluted sewage water to enter the IJse during heavy rain. Additionally, source water that previously ended up in the main sewer was connected directly to the IJse. Parts of the municipal sewerage that were in poor condition were also repaired.
With these works, the sewerage has been renewed, focusing on better water quality and a more thoughtful discharge of rainwater.
For questions about the sewerage and road works, you can contact the Aquafin contact center on weekdays between 8 AM and 5 PM at 03 450 45 45 or via contact@aquafin.be.
Based on information from the official source: Gemeente Hoeilaart (29/10/2026)