Istanbul’s water authority, the Istanbul Water and Sewerage Administration (İSKİ), released its latest reservoir data on Sunday, November 8, 2026, following a spell of intense rain and melt‑water runoff. The agency reported that the combined average fill level of the city’s ten major reservoirs rose to 61.96%, a figure that not only surpasses the typical level for early November but also marks the highest percentage recorded for the same date over the past ten years.

The surge was driven by an unusually heavy precipitation event, measured at 985.54 kilograms of rain per square metre – equivalent to roughly 986 mm – which is the most intense rainfall for this calendar point in the last decade. The abundant water input lifted the levels across all reservoirs, though the degree of increase varied considerably.

The most dramatic rise was observed at Darlık Reservoir, which now stands at 95.08% full, making it the most saturated water body in the Istanbul system. Close behind are Istrancalar at 89.77% and Ömerli at 83.20%. Other reservoirs reported the following fill percentages: Elmalı 69.67%, Alibey 80.08%, Büyükçekmece 40.83%, Sazlıdere 42.47%, Terkos 51.64%, and Kazandere 12.20%.

At the opposite end of the spectrum, Pabuçdere Reservoir recorded the lowest level at 7.89%, indicating that despite the recent rains, some upstream catchments remain critically low. This disparity underscores the uneven distribution of water resources across the metropolitan area and the ongoing challenges of managing supply during fluctuating seasonal conditions.

İSKİ’s spokesperson noted that the recent rainfall has temporarily eased pressure on the city’s water supply, especially after a dry summer that had driven reservoir levels down. However, officials cautioned that the high average fill does not guarantee a long‑term surplus, as future precipitation patterns remain uncertain and demand is projected to rise with the approaching winter months.

The data release comes amid broader discussions about Istanbul’s water security strategy, including potential infrastructure upgrades, demand‑management measures, and the exploration of additional storage options. Analysts point out that maintaining reservoir levels above the 60% threshold is crucial for ensuring reliable service during dry spells and for meeting the needs of a growing population.

For residents, the current figures mean that tap water supplies are expected to remain stable in the near term, but authorities urge continued conservation practices, especially in districts that rely heavily on the lower‑filled reservoirs. The public can monitor ongoing updates through İSKİ’s official website and local news outlets.

Source: https://www.haberturk.com/bilgi/foto/i-ski-i-stanbul-baraj-doluluk-orani-8-kasim-2026-yagis-sonrasi-i-stanbul-da-baraj-doluluk-orani-yuzde-kac-oldu-en-dusuk-ve-yuksek-doluluk-hangi-barajda-3925822