TRÊS IRMÃOS
São Paulo · TIETE
Capacity
13,372 hm³
Coordinates
-20.669°N, 51.297°W
Operator
ONS
68.8% full
Current fill
68.8%vs 7 days ago
+2.3%gaining
vs 1 year ago
+6.0%year-over-year
7-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 July 28, 2026, TRÊS IRMÃOS is filled to 68.8% of its total capacity, holding roughly 2,372 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 2.3 percentage points, and it is 6.0 points above its level on the same date a year earlier.
Across the readings we hold for TRÊS IRMÃOS — 52 data points between August 15, 2025 and July 28, 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
- 68.8%
- Water stored
- 2,372 hm³
- Total capacity
- 13,372 hm³
- Usable capacity
- 3,448 hm³
- 7-day change
- ▲ 2.3 pts
- Year-on-year
- ▲ 6.0 pts
- Primary use
- Hydroelectric power
- River
- TIETÊ
- River basin
- TIETE
- Operator
- ONS
- Coordinates
- 20.669°S, 51.297°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 68.8% | 2,372 |
| 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 |
| 19 Jun 2026 | 77.4% | 2,668 |
| 12 Jun 2026 | 65.5% | 2,257 |
| 5 Jun 2026 | 62.8% | 2,165 |
| 29 May 2026 | 61.8% | 2,129 |
| 22 May 2026 | 60.3% | 2,080 |
| 15 May 2026 | 57.0% | 1,967 |
Frequently asked questions
What is the current water level of TRÊS IRMÃOS?
As of July 28, 2026, TRÊS IRMÃOS is at 68.8% of its capacity, holding approximately 2,372 hm³ of water, according to ONS – Operador Nacional do Sistema Elétrico data.
Is TRÊS IRMÃOS reservoir full?
No. As of July 28, 2026, TRÊS IRMÃOS is within its normal operating range at 68.8% of its capacity, so it is not full.
Is the water level at TRÊS IRMÃOS rising or falling?
The level at TRÊS IRMÃOS is rising — it gained 2.3 percentage points over the latest week on record.
How much water can TRÊS IRMÃOS hold?
TRÊS IRMÃOS has a total capacity of 13,372 hm³, of which about 3,448 hm³ is usable storage.
Where is TRÊS IRMÃOS reservoir located?
TRÊS IRMÃOS is located in São Paulo, Brazil, within the TIETE basin (coordinates 20.669°S, 51.297°W).
What is TRÊS IRMÃOS used for?
TRÊS IRMÃOS is used primarily for hydroelectric power, and is managed by ONS.