Safety and health

Safety and health

Swimming in an open water area is never without a risk. In contrast to water in a swimming pool, special circumstances can come up: cold, local pollution, obstacles under water, lightning storm etc. Water in canals can contain an increased concentration of bacteria and microorganism. Besides, there is an increased chance of infections in stomach- and bowels, eyes, ears and skin (with open wounds).

Safety, health and the education on forehand is very important for the ACS. When you have (little) open wounds, we discourage participation. We recommend all swimmers to get a Tetanus injection. Another risk is undercooling. We recommend, especially to unexperienced swimmers, to swim with a wetsuit and sufficient training. It helps you to swim the Amsterdam City Swim successfully.

We use the expertise of the KNRM, supervisors, input from Waternet, the (water)police, fire department, GGD and doctors to improve our protocol every year.

But circumstances change every year and we have to oversee all the risks. The quality of the water is measured by Waternet. For the past 4 years the water complied with the norms of swimming water, but the weekend of September the 6th 2015 an exceptional situation came up. 

Temperature of the water 2015

The temperature of the canal water was 16,5 degrees Celsius during this City Swim. This was one of the reasons that 2015 was an extraordinary edition. Previous years the temperature was around 19 degrees. Despite the truncation of the trail in 2015, 7% of the participants got undercooling symptoms, ten swimmers had to be transferred to the hospital with an ambulance. All ten could go home the same night.

GGD investigation 2015

A health investigation with the participants of the Amsterdam City Swim 2015 was done by the GGD Amsterdam in cooperation with the organization of de ACS, the RIVM and GGD Utrecht. The goal of this investigation was to find answers to all the questions the GGD gets about swimming in canal and the health risks. 


During de Amsterdam City Swim the safety of the swimmers is guaranteed by the KNRM lifeguards in the water and supervisors on the quay. An EHBO post and rest area is placed every 500 meter. 

What can you do yourself?

Undercooling and injuries can be prevented if you wear a wetsuit that fits well. If you are well prepared and had sufficient training, you will engulf less water and decrease the chance of getting infection diseases.

In case you have specific questions about your health and the possibilities to participate, we recommend you to consult your doctor. You should also consult your doctor for questions about rare infection diseases like Leptospirose (disease of Weil), hepatitis A etc.

On the day of the event a team of doctors will be available who can provide all participants of final suggestions and answers.