In 2025, 98.84% of tap water on mainland Portugal met safety standards, according to an annual report published on September 29 by ERSAR, Portugal’s public water and waste services regulator. The figure has remained close to 99% for the eleventh consecutive year, although it dipped slightly from 98.86% in 2024.
The overall score is based on two indicators: whether water suppliers carried out all the required tests (99.91%) and whether the samples met the relevant standards (98.93%). Of the nearly 393,000 tests conducted on water in distribution networks, 4,235 failed to meet the standards — around 1%.
The regulator stresses that water supplied through the public network is safe to drink. In ERSAR’s assessment, the deviations identified do not make the water unsafe.
Of Portugal’s 278 municipalities, 225 scored 99% or higher, with all tests meeting the standards in 42 of them. Only two fell below 95%: Marco de Canaveses, in Porto district, and Fornos de Algodres, in Guarda district. In Marco de Canaveses, the score was dragged down by samples taken from fontanários, public drinking-water fountains. According to Rodrigues, tap water in the local network is of excellent quality, and the fountains are best avoided altogether. In Fornos de Algodres, the issue was administrative: the technician conducting the tests had an expired certification.
Around 38% of the failures were microbiological, meaning they were linked to problems with disinfection. Another 31% involved pH levels, which depend on the water’s natural properties. Most issues occur in small water networks in the country’s inland regions, where local authorities often manage the supply. The regulator recommends that these municipalities connect to larger operators, which collect and treat the water before delivering it to local networks.
Neither Lisbon nor Porto features among the municipalities flagged for poor results. In the capital, a single company, EPAL, manages the supply from source to tap — a model ERSAR considers the most reliable. In Porto, water is distributed by the municipal company Águas e Energia do Porto, which receives its supply from a major regional operator. The difference between the two cities is more noticeable in everyday life: Lisbon’s water is harder because it passes through limestone formations, so limescale builds up more quickly in kettles and washing machines.
The report does not cover private wells and boreholes. ERSAR has warned that water from these sources may be contaminated. Those who are not connected to the public water network should therefore have their water tested regularly.
