Portugal in 2026: a record-rich winter even reaches the Algarve, but Alentejo lags
Mainland Portugal entered 2026 with reservoirs at 95 % of capacity — the strongest reading in modern records — and the Algarve, historically the most stressed region, finally exceeded the national average. Here is the data.
Portugal's water-management cycle has been dominated by the Algarve drought since 2017. That story changed materially in 2026. The Portuguese Environment Agency (APA) and the National Water Resources Information System (SNIRH) both report mainland reservoir storage at a level not seen in the modern record, with even the historically driest regions running at or above average. This briefing summarises what the public record shows as of May 2026.
The 2026 figures — and the Algarve surprise
APA's weekly reservoir bulletin reported mainland Portugal at 12,610 hm³ of stored water as of late February 2026 — 95 % of total reservoir capacity [1]. That is a record-rich reading even compared with the deep-baseline years of the early 2000s, and follows a wet winter that began in October 2025 and extended through February 2026.
The most striking finding is the Algarve. The southern coastal strip, traditionally Portugal's most water-stressed region, reached an average reservoir level of 87 % — exceeding the national average for the first time in the SNIRH record [1]. The Tagus basin, which supplies Lisbon among others, sat at 91.3 % availability in late January.
Alentejo is the asymmetry
Inland of the Algarve, the Alentejo — Portugal's agricultural heartland — sat at 68.4 % storage as of early December 2025, materially below the national mean [2]. Alqueva, the largest reservoir in Western Europe and the cornerstone of the Alentejo irrigation system, was at 86.5 % by mid-winter, prompting authorities to release more water for the agricultural sector heading into 2026.
The Alentejo asymmetry is partly seasonal — the basin's catchment dynamics lag wetter coastal patterns — and partly structural, as intensive irrigated farming (olives, almonds, vineyards) keeps the regional withdrawal-to-recharge ratio higher than the national average even in good water years.
A wet year inside a long-term Mediterranean trend
WRI Aqueduct classifies most of southern Portugal — the Algarve, southern Alentejo and parts of the Tagus catchment — in the "high" to "extremely high" baseline water stress band, comparable to the Spanish southeast on long-term metrics [3]. A 95 %-full national reservoir picture is good news for short-term supply, but it does not change the underlying climate trend toward longer dry summers and shorter recharge windows.
Officials from APA and the Ministry of Environment have publicly framed the current position as supplying mainland Portugal "for two to three years" if current demand patterns hold — a useful planning horizon, not an open-ended security blanket. The 2017–2019 drought sequence showed how quickly the buffer can deflate when consecutive dry winters arrive.
Policy moves and signals to watch in 2026
Portugal's National Plan for Water-Use Efficiency, updated in 2024, sets targets for irrigation modernisation and urban network-loss reduction through 2030. The Algarve's desalination plant, in commissioning at Albufeira, will add structural redundancy to the southern coastal supply once operational; first-stage delivery is targeted for late 2026 [4].
For week-to-week readings, the SNIRH weekly bulletin and APA's reservoir dashboard are the canonical sources. The European Drought Observatory adds a comparative SPEI lens. The most-informative single inflection is end-of-March precipitation: it determines whether late-spring inflows extend the wet-year buffer or whether the dry season starts drawing the buffer down ahead of schedule.