Questions and answers about PFAS in water

Is it safe to swim in ditches, canals, and ponds?

Want to take a dip on a hot day? Wonderful. You can, but not everywhere. It is best to swim at an official swimming location in the area. We check our locations for pathogenic bacteria and blue-green algae at least once every two weeks during the swimming season (May 1 - October 1). However, when it is very hot, the water quality of the swimming water can change quickly. Therefore, before swimming, check the most up-to-date information atwww.zwemwater.nl, via the ZwemApp, or on the signs at the swimming location. 

HHNK measures water quality at officially designated swimming locations. The results can be found atwww.zwemwater.nl. In addition to the regular measurements for bacteria and blue-green algae, the 15 HHNK swimming water locations were tested for PFAS in 2024. At all locations, the values are below the recommended swimming water values. The results can be found on the website of the Province of North Holland. 

What are the consequences of the presence of PFAS in surface water for the quality of drinking water in Hollands Noorderkwartier?

The surface water in our area is not used by a drinking water company to produce drinking water. More information about PFAS and drinking water can be found on the RIVM website.

Where does PFAS pollution come from?

PFAS is everywhere: in ditches, canals, lakes, and also in the soil. Because these substances do not break down, they remain in our environment for years. PFAS contamination is caused by pollution from wastewater treatment plants (WWTPs), overflows or discharges from industry, and, for example, the use of firefighting foam. 

What measurements are being carried out in Hollands Noorderkwartier?

  • HHNK dredges ditches, streams, and canals. This prevents flooding during heavy rainfall. Dredged material is the mud that lies at the bottom, and we always check it carefully for PFAS. More than 99% of the dredged material checked is reusable. If it contains more PFAS than is permitted by law, it is taken to specialists. The specialists store the PFAS-contaminated dredged material in large, sealed depots in the ground or clean the dredged material. See the Dredging page. 
  • HHNK monitors various substances in surface water within the WFD monitoring network and also conducts research into the spread of PFOS. 
  • HHNK also monitors PFAS in wastewater. Nationwide research is being conducted into the removal of PFAS in treatment plants. We are closely following this research.
  • HHNK has recently tested 15 swimming locations for PFAS. 

Other questions

If you have any further questions about PFAS, please visit: