TRÊS IRMÃOS
São Paulo · TIETE
Capacity
13,372 hm³
Coordinates
-20.669°N, 51.297°W
Operator
ONS
65.1% full
Current fill
65.1%vs 7 days ago
+3.5%gaining
vs 1 year ago
N/A7-day trend
↑rising
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Technical specifications
| Total capacity | 13,372 hm³ |
| Usable capacity | 3,447.98 hm³ |
| Primary use | Hydroelectric |
| Operator | ONS |
| River | TIETÊ |
| Province | São Paulo |
| River basin | TIETE |
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -20.669, -51.297 · Open in Google Maps
About TRÊS IRMÃOS
As of September 9, 2026, TRÊS IRMÃOS is filled to 65.1% of its total capacity, holding roughly 2,243 hm³ of water out of a maximum 13,372 hm³. At this level the reservoir is within its normal operating range. Of that total, about 3,448 hm³ is usable (live) storage.
Over the most recent week on record the fill level has risen by 3.5 percentage points.
Across the readings we hold for TRÊS IRMÃOS — 52 data points between September 26, 2025 and September 9, 2026 — the level has ranged from a low of 56.4% (November 28, 2025) to a high of 92.8% (March 27, 2026). On average the reservoir is fullest around March and at its lowest around November.
It is operated by ONS primarily for hydroelectric power. It lies within the TIETE basin at 20.669°S, 51.297°W.
Key facts
- Current fill level
- 65.1%
- Water stored
- 2,243 hm³
- Total capacity
- 13,372 hm³
- Usable capacity
- 3,448 hm³
- 7-day change
- ▲ 3.5 pts
- Primary use
- Hydroelectric power
- River
- TIETÊ
- River basin
- TIETE
- Operator
- ONS
- Coordinates
- 20.669°S, 51.297°W
- Last updated
- September 9, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 9 Sep 2026 | 65.0% | 2,243 |
| 4 Sep 2026 | 61.5% | 2,122 |
| 28 Aug 2026 | 59.7% | 2,058 |
| 21 Aug 2026 | 64.6% | 2,229 |
| 14 Aug 2026 | 69.0% | 2,379 |
| 7 Aug 2026 | 69.0% | 2,379 |
| 31 Jul 2026 | 69.8% | 2,408 |
| 24 Jul 2026 | 66.5% | 2,293 |
| 17 Jul 2026 | 70.9% | 2,444 |
| 10 Jul 2026 | 76.3% | 2,632 |
| 3 Jul 2026 | 82.5% | 2,844 |
| 26 Jun 2026 | 80.1% | 2,763 |