Whether it’s a fountain or a swimming pool, there are non-negotiable design components. Without an effective filtration system, proper chemical or biological treatment, and a well-sized recirculation system, water quality rapidly deteriorates, with obvious hygiene consequences after just a few days. Yet, these very elements—fundamental—are sometimes overlooked or treated as secondary during the design phase.
The issue isn’t just performance, but primarily safety, which must always come first. Every year, serious accidents, sometimes fatal, are reported, linked to improperly designed or installed suction systems: people become trapped in the nozzles due to excessive vacuum or non-compliant devices.
At this point, it’s legitimate to ask: why talk about swimming pools when we’re talking about fountains? Because, from a regulatory perspective, fountains and swimming pools are the same. Italy and Europe share a technical framework for the design, installation, and management of systems. The regulatory framework for public swimming pools is UNI EN 13451-1, UNI EN 13451-3, and UNI 10637, which must be considered in an integrated manner, as each defines complementary requirements. For residential swimming pools, however, the reference standard is UNI EN 16713-2.
The operation of a fountain or swimming pool is, essentially, a continuous cycle: water is drawn in through skimmers and bottom drains, conveyed to the filtration system, recirculated by the pump, and then chemically treated to maintain its health and safety. A seemingly simple mechanism, but one that requires a very precise balance.
There’s a fundamental rule in pool design, valid for both public and private pools: every suction system must be able to function safely even in the event of a malfunction or blockage of one of the devices. Among the most delicate aspects is managing the suction force of the nozzles, because if it’s not properly calibrated, the nozzle ceases to be a technical component and becomes a critical point: a veritable “grip” capable of trapping a limb or pinning the body against the surface, with potentially fatal consequences. Then there’s a counterintuitive element: a very powerful nozzle placed in a shallow area of water—rather than the deepest part—can increase the risk, especially for children, because it facilitates the downward drag effect, making it difficult to free oneself even in conditions that would, at first glance, appear safer.
In public pools—unlike private ones—the law requires at least two suction points connected by a pipe at least 2 meters long. The idea is simple but effective: if one of the two is blocked, the other continues to work, preventing the formation of a dangerous vacuum that could trap a person underwater. But simply doubling the nozzles isn’t enough; how they’re connected must be considered: the two branches of the pipe must be as balanced as possible and of limited length, so that the flow is evenly distributed. If the design is flawed, the water will “prefer” one of the two paths, creating an imbalance: one nozzle works more than the other and ends up behaving, effectively, as a single suction point—with all the resulting risks, especially for partial or hair entrapment.
In many cases, therefore, two devices are not enough. The number must be sized based on the pump’s flow rate: the key parameter to be respected is the suction speed on the screen, which must remain below 0.5 m/s. In other words, the more water that must pass, the larger the usable surface area of the screens must be, so as to cushion the suction force. Added to this is another design constraint: according to UNI EN 13451-1, the screen holes cannot exceed 8 mm in diameter, a significant detail when balancing safety and performance.
Another little-known aspect concerns safety tests. In swimming pools, all devices must pass specific tests, including the so-called hair entrapment test, performed at maximum suction capacity. These checks are designed to avoid dangerous situations, such as the risk of a person becoming trapped by suction.
Despite the seriousness of some cases, it’s important to put them into context: pool accidents are relatively rare, and even more so in fountains. However, when critical events do occur, they’re often not fatal, but rather a combination of multiple factors, such as:
- Missing or improperly secured grates. The grate covering the bottom inlet is a crucial element, and its absence poses a serious risk. In pools built to standards, it’s secured with multiple screws to prevent it from coming loose.
- Suction concentrated in a single point. If the skimmers are closed and only the bottom inlet remains active, all the suction force is concentrated there, increasing the danger. Fortunately, modern, well-designed systems ensure balanced distribution.
- Sudden illnesses, cramps, or other physical conditions can have a significant impact, especially in children, as they can impair their ability to react and make it difficult to move away from a suction point promptly.
- Lack of supervision. In public swimming pools, the presence of a lifeguard is essential. But even in family settings, direct adult supervision remains indispensable.
- Mancanza di sorveglianza. Nelle piscine pubbliche, la presenza del bagnino è fondamentale. Ma anche nelle situazioni familiari, la supervisione diretta degli adulti resta insostituibile.
A swimming pool can be a safe environment, even for children, only if current regulations are respected, and a few fundamental conditions are met:
- design and construction compliant with standards;
- use of certified components;
- routine maintenance;
- presence of redundant systems (such as a double bottom intake);
- careful and professional supervision.
Accidents, in most cases, are not inevitable. They are the result of avoidable mistakes. And precisely for this reason, understanding how these systems really work is the first step to preventing them.
