The so-called 'brown challenge' (reto marrón) is sweeping across Spain, leading to the closure of more than 300 swimming pools and posing a serious public health risk. The trend, which began as a grim prank on Instagram and TikTok, involves individuals defecating directly into public pools or concealing faeces in a bag inside a swimsuit to release it in the water, all while recording the act to post online with the aim of getting the pool closed.
Health Hazards and Vulnerable Swimmers
The behaviour introduces numerous hygiene hazards, as faeces can transmit viruses such as norovirus, bacteria like Salmonella, and parasites including Cryptosporidium—which pool chlorine does not effectively kill. Swimmers who accidentally swallow or inhale contaminated water may suffer from stomach pains, vomiting, fever, diarrhoea, and other ailments. Children are particularly vulnerable, as they tend to swallow more water while swimming.
By law, pools must remain closed for 24 to 48 hours after any faecal incident, during which time they are thoroughly cleaned, filtered, and tested multiple times to ensure safety. In some cases, pools have had to be completely drained and refilled, using thousands of litres of water—a costly process. Small-town pools are often the most affected, as they serve as hubs for family gatherings, leading to cancelled events and leaving locals without swimming facilities during the hottest days.
Municipal Crackdowns and Fines
In response, around 50 municipalities have issued public alerts, and local councils are imposing fines ranging from €1,000 to €3,000 on offenders, who are also banned from re-entering the pools. In Picassent, the city council has escalated cases to court, fining several youngsters €5,000 each. Pools are also increasing police surveillance, though identifying perpetrators remains challenging as pools cannot install cameras or demand identification on entry.
This is not a new phenomenon; the city of Zamora has seen some of its pools close six times already this year. In 2025, over 300 pools were shut for the same reason. The ongoing trend continues to disrupt communities and strain resources, with authorities urging vigilance and strict enforcement of penalties to deter future incidents.
