Leave that fire hose alone – Legionella risks at summer camps

A seemingly innocent scene

You arrive at camp, the sun is beating down, and the children playfully dive into a freshly prepared above-ground pool. To quickly supply a large amount of water, the staff grabs the nearest fire hose from the hallway. Convenient, right? Unfortunately, it's also risky: the hose and feed line of such a reel are practically stagnant year-round. Stagnation plus summer temperatures = an ideal breeding ground for Legionella. As soon as that water ends up in the pool or—worse yet—in water pistols, children inhale the microdroplets, potentially full of bacteria.

Legionella in a nutshell

Legionella bacteria thrive in stagnant or slowly flowing water between 25 and 45°C. Inhalation of aerosolized droplets can cause severe pneumonia (Legionnaires' disease) or the milder Pontiac fever. The elderly, smokers, and people with weakened immune systems are particularly at risk, but healthy children can also become ill. The impact of the post-COVID era, where other groups have also contracted lung infections, is not yet sufficiently understood. Therefore, prevention is legally required for many collective installations. The Department of Healthcare also emphasizes the importance of flushing pipes at home, especially when returning from vacation.

Swimming pool + water pistols = aerosol cannon

Recently we encountered the following situation:

During a camp activity, due to the warm weather, a swimming pool was set up and filled with the fire hose. Water pistols were also provided, which the children filled in the pool. Each time a jet was fired while playing, the spray at the water pistol was clearly visible. Fortunately, this is only used outdoors, where air circulation is excellent, but this doesn't prevent the children from inhaling some of the aerosols. In just a few hours, this creates the perfect scenario for an outbreak – especially if multiple camps use the same fire hose or the hose is left in the sun.

A fire hose has only one purpose: extinguishing fires. Therefore, it is explicitly warned that it must never be used for anything else, and that it must be equipped with a non-return valve (check valve) on the branch. If you do open the hose, the stagnant water will be released immediately – often in a spray mode, which creates a very high level of aerosol formation.

A chlorine tablet: necessary, but not a panacea

We were delighted to see a container floating in the pool containing a chlorine tablet. While this floating chlorine tablet is essential for safety, it takes time to dissolve and reach an effective concentration (e.g., ≥ 1 ppm free chlorine). Adding the tablet just before swimming gives bacteria free rein. Moreover, the chlorine level drops rapidly due to sunlight and organic pollutants (sand, grass, sunscreen). Regular adjustment is therefore essential, ideally even measuring it if the pool is used for an extended period and the facility is available.

Some practical tips for camp organizers

Doing	Why
Fill with a drinking water point , not with the fire hose.	This avoids the use of potentially contaminated water due to long periods of stagnation.
Rinse the hose thoroughly for at least 2 minutes before use.	In case of any contamination in the hose or the drinking water, this will flush away the highest concentrations
Ensure sufficient and timely disinfection : 1–3 ppm free chlorine, at least 60 minutes for above ground pools	Kills (after contact time) bacteria and keeps the water clear
Limit spraying if there is any doubt about the quality : if there is any doubt about the quality, do not use sprayers or items such as water pistols.	Fewer aerosols → less inhalation
If used intensively , refresh the water every few days	Breaks bacterial growth cycles

Signals to Never Ignore

If anyone at the camp suddenly develops a high fever, headache, muscle aches, or a cough after playing with fire hose or swimming pool water, report this immediately to a doctor and explicitly mention any contact with potentially contaminated water. Legionellosis is notifiable; rapid diagnosis and treatment with antibiotics significantly reduce complications.

Conclusion: Prevent a summer camp from ending in an outbreak

A fire hose is designed for emergencies, not for pool fun. The combination of stagnant water, high outdoor temperatures, and enthusiastic children poses an unnecessarily high Legionella risk. With simple precautions—a safe drinking water source, timely chlorine, and limited or no spraying—camp can remain a place for fond memories instead of pneumonia. So: leave that fire hose hanging and choose safe, running drinking water . The children won't notice the difference, but their lungs will.

If you have any questions about this, you can always contact us without obligation via:

jonatan@safewaterconsult.be