The Chamber of Deputies has unanimously approved an amendment to the Sports decree which provides for the closure of swimming pools open to the public if they have non-compliant suction nozzles. The debate reached Parliament after several people, mostly children, lost their lives in recent weeks after being trapped against the intake vents.
For those who do not comply, the risk is the immediate closure of the facility: controls will likely be strengthened, while for the adaptation of public swimming pools, the Government will allocate 4.7 million for 2026.
It must be said, however, that these provisions are not yet official: as reported on the website of the Chamber of Deputies, the provision is now being examined by the other branch of Parliament, namely the Senate.
Immediate closure of the plant: what the amendment provides
The approved text intervenes on the water recirculation system, i.e. on the system that aspirates and purifies the water from the pool. According to the amendment, «in public or private swimming pools intended for public use, including those for collective use, the recirculation system for purification and, in particular, the water intake inlets such as bottom grates, nozzles or any other material used for the purpose, must guarantee the safety necessary to prevent swirling suction phenomena with a suction cup effect towards every part of the bathers’ bodies».
In case of violation, the immediate closure of the plant is ordered until the obligations set out therein are fulfilled. The law then specifies that “the further obligations and responsibilities provided for by current legislation regarding the safety, management and maintenance of swimming pools and swimming facilities remain unchanged”, and in the last part it dedicates a passage to economic coverage: for the adaptation of public swimming pools, “a fund with an endowment of 4,725,000 euros for the year 2026” is established.
Why a swimming pool sucks water: how a nozzle works
To understand the risk that non-compliant outlets or grates represent, we need to start from a simple question: why does a swimming pool suck in water? Each tank must be equipped with a filtration system, otherwise the water stagnates and microorganisms and algae potentially harmful to health can proliferate. The system then sucks the water from the tank, purifies it and reintroduces it. And this is where the nozzles come into play: to make the cycle work, the pumps generate a pressure difference that pushes the water towards the nozzle. To keep the water clean, the suction must therefore be quite rapid.
By multiplying the pressure difference created by the pump by the area of the suction nozzle, we obtain the force that “sucks” a body in the immediate vicinity of the nozzle. The values may vary depending on the size of the pool and the number of outlets, but we are talking about rather large numbers. For a single suction system we are talking about forces comparable to the weight of a 150-250 kg body crushing the bather against the socket. These are more than enough forces to trap a person, especially a child or teenager.
The mechanism that makes everything so dangerous is the so-called “sucker effect”. When a body rests on the nozzle, the pump continues to generate a depression but the water no longer passes through, because the grate is blocked by the body itself. This creates a situation similar to a vacuum, from which it is extremely difficult to free oneself without turning off the system. It’s the same principle (on a much larger scale) as when we cover the mouth of a vacuum cleaner with our hand: the hand stays attached precisely because it prevents the passage of air.
But be careful: this does not mean that swimming pools are dangerous in themselves. The risk is avoidable if manufacturers and installers respect the regulations, if maintenance is done correctly and if swimmers pay attention.
And it is precisely here that standard grilles and outlets make the difference. A single suction device is more dangerous, because it must necessarily produce a greater suction force: for this reason, in swimming pools for public use, the regulations require at least two devices connected to each other, sized so that, if one becomes obstructed, the other (or others) can still pass 100% of the flow rate, preventing the trapping depression from forming.
The European rules (the technical standards UNI EN 13451-1 and UNI EN 13451-3, supported in Italy by UNI 10637 for the sizing of the pipes) then set some concrete limits: the speed of the water on the grate must not exceed 0.5 m/s (about 1.8 km/h), that in the suction pipes 1.7 m/s, the holes in the grate must have a maximum diameter of 8 mm and each grate must pass hair entrapment, obstruction and load tests.
There are also peripheral suction grills, designed to distribute the pressure difference over a larger surface and reduce the net suction force near the intake.
