Lisbon, Sept. 29, 2026 (Lusa) - Mainland Portugal recorded a tap water safety rate of almost 100% last year, marking the 11th consecutive year this has been the case, according to data released on Tuesday by the Water and Waste Sector Regulatory Authority (ERSAR).
According to this year's Annual Report on Water and Waste Services (RASARP), covering 2025, 98.84% of tap water is safe, a figure derived from combining the number of mandatory analyses (99.91%) with compliance with parametric figures (98.93%).
With the data now available, this marks the 11th consecutive year in which the water quality indicator has stood at 99%, according to the report to which Lusa had access, according to which the rate of safe water in the upstream system (the process of abstraction, treatment and transport to municipalities) remains at 99.69%, whilst the rate of safe water in the downstream system (distribution to consumers) stands at 98.84%.
Susana Rodrigues, director of ERSAR's quality department, says there are «some problems» with smaller systems, and adds that upstream systems offer greater safety, not least because they are more professionally managed.
Last year, 74,473 analyses were carried out on upstream water, all of which were scheduled, and of these only 229 (0.31%) were non-compliant.
For safe water at the point of use, 392,667 analyses were carried out (99.1% of the planned total) and 4,235 (1.07%) were non-compliant, a figure partly explained by poor quality at some drinking fountains.
Compared with the previous year, the safe water rate fell from 98.86% in 2024 to 98.84% in 2025, whilst the number of districts (225, or 81%) with water quality of 99% or higher remained the same, and 42 districts (15%) recorded 100% safe water (five fewer than in 2024).
There are also 51 districts with safe water levels above 95% but below 99%. This figure is identical to that of 2024.
According to ERSAR's maps, the best results (99% or higher) are found across most of the country, with the exception of some regions in the Alentejo and districts in the central and northern inland areas.
Most non-compliance relates to pH (31%) and microbiological parameters (38%), due, respectively, to the natural characteristics of the water and to failures in disinfection systems.
Two districts are in the ‘red' zone, having failed to exceed 95%: Marco de Canaveses and Fornos de Algodres.
In the first case, the lower figure relates to analyses of water from drinking fountains, which, according to Susana Rodrigues, should not even be used as they coexist with tap water, which is of «excellent quality».
In Fornos de Algodres, it was purely an administrative issue, relating to the analysis technician's expired certification.
«The key message is that there is no unsafe water,» she said during the presentation of the report, highlighting the importance of districts connecting to the mains water supply.
Vera Eiró, chair of the ERSAR Board of Directors, also argued that «the greatest assurance comes from connecting a local distribution network to a central supply network», adding that the trend is for municipalities to be better coordinated, centred around a joint body.
According to ERSAR, only 62 districts have a vertically integrated structure, responsible for both the main supply and distribution networks, and there are still 180 springs serving as the sole source of water for human consumption, supplying 8,797 inhabitants.
In the interior of the country, the distribution networks are the most difficult to manage, with a greater number of supply zones.
If a district has many supply zones, often managed by parish councils, this can lead to «failure to meet microbiological standards»; therefore, the ideal solution is for these areas to be connected to the upstream systems, emphasised Susana Rodrigues She also explained that new analytical parameters were introduced last year, but that there was no decline in quality.
Last year, ERSAR carried out 60 inspections of water supply operators, issuing notices of infringement to 32 (mainly for failures in data disclosure), whilst the food safety regulator, ASAE, carried out 128 inspections of private water supply systems.
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