Istanbul’s water authority (İSKİ) released its latest measurements on 5 November 2026, showing that the city’s overall reservoir fill rate climbed to 59.65 % – a rise of 4.90 percentage points from the previous day’s 54.17 %. The improvement follows a series of heavy rain showers that fell across the metropolitan area in early November.

The data, published by Habertürk, detail the status of the ten principal dams that supply Istanbul’s megacity. Darlık Dam topped the list with a fill level of 90.34 %, effectively nearing full capacity. Ömerli and Alibey followed with 78.83 % and 72.12 % respectively, while Elmalı and Istrancalar also remained above the 50 % threshold at 67.98 % and 59.77 %.

Conversely, several smaller reservoirs continue to run low. Kazandere recorded only 4.32 % and Pabuçdere a mere 3.08 % of their total storage, highlighting a persistent imbalance among the system’s water sources. Mid‑size dams such as Terkos (40.49 %), Sazlıdere (34.64 %) and Büyükçekmece (33.03 %) sit in the middle range, still far from the levels needed to guarantee long‑term security.

For context, ISKI’s figures show a dramatic year‑on‑year increase. On 4 November 2025 the combined fill rate was roughly 22.4 %, climbing to 54.75 % on the same date in 2026 – an uplift of about 32.35 percentage points. The sharp jump reflects both the recent precipitation and ongoing efforts to manage the city’s water balance after several years of drought‑related stress.

Istanbul, home to over 15 million residents, relies on these reservoirs for drinking water, irrigation and industrial use. The city’s water demand peaks during the hot summer months, making the current reservoir status a critical indicator for municipal planners. While the surge to nearly 60 % overall capacity is encouraging, officials caution that the disparity among dams means that continued monitoring and rain‑dependent replenishment remain essential.

“The recent rains have helped raise the water levels, but we must continue to use water responsibly and monitor the lower‑filled reservoirs closely,” an ISKI spokesperson said in a statement released alongside the data.

The full set of measurements, including individual dam percentages, can be accessed through Habertürk’s report (https://www.haberturk.com/bilgi/foto/5-kasim-i-ski-baraj-doluluk-oranlari-2026-i-stanbul-un-su-rezervlerinde-son-durum-i-stanbul-baraj-doluluk-oranlari-yuzde-kac-oldu-3925032).