Reservoir Watch
Real-time fill levels for 102 Brazilian hydroelectric reservoirs across 19 states. Data updated 3× daily.
Average fill
75.2%
Total volume
240 km³
Reservoirs
102
Low level
9
By ONS subsystem
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Brazil at a glance
National average fill
75.2%
240,217 of 319,365 hm³ usable storage
Reservoirs
102
States
19
Usable capacity
319 km³
Volume stored
240 km³
Low level
9
National fill — multi-year
ONS subsystems
Click to exploreBy state
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São Paulo
19 reservoirs
Average fill
71.3%
Minas Gerais
19 reservoirs
Average fill
71.6%
Goiás
13 reservoirs
Average fill
60.1%
Pará
4 reservoirs
Average fill
86.6%
Paraná
11 reservoirs
Average fill
91.2%
Bahia
4 reservoirs
Average fill
82.0%
Amazonas
1 reservoirs
Average fill
89.9%
Tocantins
4 reservoirs
Average fill
75.8%
Mato Grosso
5 reservoirs
Average fill
77.9%
Rio Grande do Sul
6 reservoirs
Average fill
69.3%
Santa Catarina
5 reservoirs
Average fill
95.8%
Pernambuco
1 reservoirs
Average fill
84.6%
Rondônia
4 reservoirs
Average fill
56.0%
Piauí
1 reservoirs
Average fill
82.1%
Sergipe
1 reservoirs
Average fill
53.7%
Mato Grosso do Sul
1 reservoirs
Average fill
97.4%
Alagoas
1 reservoirs
Average fill
79.9%
Rio de Janeiro
1 reservoirs
Average fill
35.3%
Amapá
1 reservoirs
Average fill
105.0%
All reservoirs
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Dataset coverage
Tracked
102
reservoirs
With data
102
reservoirs
Tracked capacity
571,021
hm³
Source: ONS — Operador Nacional do Sistema Elétrico · ANA — Agência Nacional de Águas
Covers major reservoirs in the ONS hydrology monitoring system. Brazil has thousands more smaller reservoirs not yet tracked.
About reservoirs in Brazil
As of July 25, 2026, the reservoirs we track across Brazil that report live levels hold roughly 240,217 hm³ of water — about 42.1% of their combined capacity. Taken together, Brazil's reservoirs are within their normal operating range.
Across the region, 9 are low. PEDRA DO CAVALO is the fullest at 105.0%, while LAJEADO is the lowest at 30.6%.
Over the most recent week on record, 17 reservoirs rose and 16 reservoirs fell across Brazil.
Storage figures for Brazil come from ONS; the most recent reading is from July 25, 2026. Each reservoir below links to its own page with full history and seasonal context.
Brazil at a glance
- Reservoirs tracked
- 102
- Average fill
- 42.1%
- Water stored
- 240,217 hm³
- Combined capacity
- 571,021 hm³
- Fullest
- PEDRA DO CAVALO (105.0%)
- Lowest
- LAJEADO (30.6%)
- Last updated
- July 25, 2026
Frequently asked questions
How full are reservoirs in Brazil right now?
As of July 25, 2026, the reservoirs tracked in Brazil that report live levels are 42.1% full overall, holding about 240,217 hm³ of water.
How many reservoirs are there in Brazil?
reservoirs.earth tracks 102 reservoirs in Brazil, with a combined storage capacity of 571,021 hm³.
Which reservoir in Brazil is the fullest?
PEDRA DO CAVALO is currently the fullest reservoir in Brazil, at 105.0% of capacity.
Which reservoir in Brazil is the lowest?
LAJEADO is currently the lowest in Brazil, at 30.6% of capacity.
Where does the reservoir data for Brazil come from?
All storage figures for Brazil come from ONS, an official source, last updated July 25, 2026.