Greece in 2026: Mornos tripled in six months, but the structural crisis is not over
Athens' main reservoir went from 15-year low to almost-full between October 2025 and April 2026 — yet EYDAP and the government still describe the underlying water crisis as a multi-year structural problem. Here is the data.
On 23 October 2025 the Mornos reservoir, which supplies the majority of greater Athens' drinking water, sat at 156.996 million cubic metres — a fifteen-year low. By 8 April 2026 it had risen to 491.629 million cubic metres, roughly tripling in six months [1]. That recovery is genuine and welcome, but it does not undo the structural drivers that the Greek government and Athens' water utility EYDAP describe as a multi-year crisis.
The Mornos rebound — and what it does not change
Mornos sits at the heart of Athens' supply system, fed primarily by snowmelt from Mount Giona and Mount Parnassus and supplemented by the Marathon and Yliki reservoirs. The 2023–2025 drought sequence, the third consecutive year of decline per EYDAP chairman George Stergiou, drew the system down faster than the spring melt could replenish it [2].
The winter 2025–2026 rains and snowfall delivered a rebound large enough to submerge the village of Kalyo under the reservoir again — a village that had reappeared months earlier when levels fell. The waterlogged Kalyo is now the visible marker of the recovery [1]. EYDAP's consistent message, however, is that the spring–summer dry season still lies ahead and consumption naturally peaks then.
Why a wet season does not equal an end to the crisis
Athens depends on a small number of reservoirs and a long-haul aqueduct system stretching to central Greece. The supply system has limited groundwater backup; tourism-driven peak demand in the islands and coastal Attica pushes draw to its summer maximum exactly when reservoir refill slows.
WRI Aqueduct rates much of southern and eastern Greece in the "extremely high" baseline water stress band, with the Cyclades and parts of the Peloponnese among the most stressed catchments in the EU [3]. A single wet winter improves the buffer; it does not reset the underlying ratio of demand to renewable supply.
The investment response
The Greek government announced in late 2025 a €2.5 billion, decade-long investment programme covering pipe replacement, smart-meter rollout and expanded wastewater reuse [4]. The plan accepts modest tariff increases as part of the funding mix and is positioned explicitly as drought-response infrastructure rather than business-as-usual maintenance.
Parallel to the national plan, EYDAP's own multi-year strategy is built around reducing system losses (currently among the highest in the EU for a capital-city utility) and adding redundancy via additional aqueduct capacity and groundwater backup. Both programmes assume that the 2026 rebound is a window of opportunity, not a return to normal.
Policy moves and signals to watch in 2026
Three signals to follow through 2026: the EYDAP weekly reservoir bulletin (Mornos, Marathon, Yliki combined), the spring–summer evaporation rate (a function of heat-dome frequency in Attica), and the parliamentary review of the €2.5 billion investment plan, which is expected mid-2026 and will determine how much of the announced funding actually flows.
For broader regional context, the European Drought Observatory's combined SPEI indicator gives a weekly comparative view of the eastern Mediterranean. The next key inflection point is end-of-September: by then, the dry season's drawdown rate will reveal whether 2026 is a sustained recovery or another sequence of slow decline.