It seems like a curious, almost impossible-to-enforce rule, but in some coastal locations in Spain, peeing in the sea is officially prohibited. The ordinances were introduced by several coastal municipalities with the aim of protecting marine biodiversity and curbing the impact of overtourism on the coast.
An environmental measure that is more than symbolic
The ban was formally introduced by the Deputación Provincial de A Coruña, which in an official communication dated June 4, 2025 included among its sanitation regulations a ban on physiological evacuation at sea or on the beach. Similar regulations have also been issued by other municipalities such as Marbella, which expressly prohibits any kind of evacuation on the beach.
The focus is especially on coastal areas subject to heavy tourist pressure. Indeed, during the summer, the population can triple, greatly increasing the anthropogenic load on an already fragile environment. Hence the need to introduce measures to preserve the marine balance and ensure sustainable use of beaches.
Why can urine in the sea be a problem?
At the chemical level, human urine is composed mainly of water, but it also contains urea, phosphorus, nitrogen, drug residues and chemicals that are potentially harmful to the environment. In small amounts, it does not pose a risk, but in high-attendance settings it can contribute to marine pollution.
One of the most troubling effects iseutrophication-a process that enriches waters with nutrients such as nitrogen and phosphorus, promoting the overgrowth of algae. As these die and decompose, they consume large amounts of oxygen, causing hypoxia or anoxia in bottom waters, with devastating effects on marine organisms.
Urine may also contain traces of medications, contraceptives, antibiotics or drugs, which end up in the marine environment and can adversely affect the health of aquatic animals. Some studies indicate that these residues can impair the reproduction of fish and marine invertebrates, or alter the behavior and metabolism of some species.
The ambiguity of science: is it really that bad?
Not all experts agree on the seriousness of the phenomenon. A paper published in 2014 by theAmerican Chemical Society argued that, in principle, peeing in the sea is not dangerous, since the ocean already naturally contains large amounts of salts and nitrogen. However, even then it recommended avoiding urinating in enclosed areas, lagoons or stretches of sea with little water exchange, where the concentration of substances can become problematic.
Ultimately, banning peeing in the sea may seem like an extreme or difficult measure to enforce, but it is part of a larger effort to empower beachgoers toward sustainable and environmentally friendly behaviors. In fragile coastal areas, where huge numbers of tourists are concentrated each summer, even small gestures, including where and how physiological functions are performed, can make a difference.
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