Water quality

Water quality

Our partner Waternet monitors the canal water on the Amsterdam City Swim course throughout the year. The quality of this water is in principle safe to swim in. A major reason for this is the construction of sewers (completed in late 1987) and the construction of a new treatment plant in Amsterdam West (2006). Since then, Amsterdam's treated sewage no longer enters the canals. In recent years, almost all 2,500 houseboats have also been connected to the sewage system. Although the water of the ACS course is not officially swimming water, the measured values are mostly within the bathing water standards. Deviations from the bathing water standard occur during precipitation that is so heavy that the sewers overflow. Therefore, Waternet also records sewer overflows on and around the swimming course. In case of unusual findings, Waternet will contact the board of the Amsterdam City Swim. The board, in consultation with all parties, can take decisions on route, passage and other matters to ensure the safety of the event.

Open water swimming

Swimming in open water is never entirely without risk. Unlike water in swimming pools, special conditions can always happen for example: cold, localised pollution, underwater obstacles, thunderstorms, etc. In canal water, the concentration of bacteria and other micro-organisms may be elevated. The risk of infections, especially of the gastrointestinal system, but also the eyes, ears and skin (especially with open wounds) are higher than compared to swimming in a swimming pool.

Together with Waternet, the Amsterdam City Swim continuously monitors water quality. We closely monitor developments, and we inform our participants accordingly. We use the expertise of KNRM lifeguards, supervisors, input from Waternet, the (water) police, fire brigade, GGD and doctors to test and, if possible, improve our protocol every year.



During the Amsterdam City Swim, safety of the swimmers is managed by KNRM lifeguards in the water and supervisors on the quay. There is also a first aid post and a rest point on the water every 500 metres.

What can you do yourself?

Swimming with open wounds is not recommended and a tetanus shot is advised. When swimming in open water, there is also a risk of hypothermia. Especially for less experienced swimmers, we recommend using a wetsuit.

In the run-up to the event, we will inform participants about the rules around wearing a wetsuit in combination with the average water temperature on the course. More information about the possibility of renting a wetsuit will also be shared.

Sufficient training will help you complete the Amsterdam City Swim properly and safely. By training sufficiently, you will take in less water and so reduce the risk of contracting infectious diseases.

If you have specific questions about your health and the possibility of participating in the Amsterdam City Swim, consult your doctor. You should also consult your doctor for specific advice on the risk of rare infectious diseases such as leptospirosis (Weil's disease), hepatitis A and other infectious diseases.

On the event day itself, an Amsterdam City Swim doctors' team will be present in the morning to provide participants with any tips and answers to questions.


Safeguard declaration

We ask all participants to sign a safeguard declaration prior to the Amsterdam City Swim.

Do you have any questions? Then of course you can always ask them via info@amsterdamcityswim.nl.

You can find more information on water quality via; www.rijkswaterstaat.nl , www.mens-en-gezondheid.info.nu.nl  and www.zwemwater.nl .

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