San Juan
Community of Madrid · Tajo
Capacity
138 hm³
Coordinates
40.377°N, 4.320°W
Operator
CHT
Current fill
89.9%vs 7 days ago
-2.1%losing
vs 1 year ago
-2.9%year-over-year
7-day trend
↓falling
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Technical specifications
| Total capacity | 138 hm³ |
| Usable capacity | 124.2 hm³ |
| Primary use | Multi-purpose |
| Operator | CHT |
| Autonomous community | Community of Madrid |
| River basin | Tajo |
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 40.377, -4.320 · Open in Google Maps
About San Juan
As of June 9, 2026, San Juan is filled to 89.9% of its total capacity, holding roughly 124 hm³ of water out of a maximum 138 hm³. At this level the reservoir is high. Of that total, about 124 hm³ is usable (live) storage.
Over the most recent week on record the fill level has fallen by 2.1 percentage points, and it is 2.9 points below its level on the same date a year earlier.
Across the readings we hold for San Juan — 418 data points between June 12, 2018 and June 9, 2026 — the level has ranged from a low of 16.7% (November 19, 2019) to a high of 92.8% (May 21, 2024). On average the reservoir is fullest around May and at its lowest around November.
It is operated by CHT primarily for multiple purposes. It lies within the Tajo basin at 40.377°N, 4.320°W.
Key facts
- Current fill level
- 89.9%
- Water stored
- 124 hm³
- Total capacity
- 138 hm³
- Usable capacity
- 124 hm³
- 7-day change
- ▼ 2.1 pts
- Year-on-year
- ▼ 2.9 pts
- Primary use
- Multipurpose
- River basin
- Tajo
- Operator
- CHT
- Coordinates
- 40.377°N, 4.320°W
- Last updated
- June 9, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 9 Jun 2026 | 89.9% | 124 |
| 2 Jun 2026 | 92.0% | 127 |
| 26 May 2026 | 92.8% | 128 |
| 19 May 2026 | 92.8% | 128 |
| 12 May 2026 | 92.0% | 127 |
| 5 May 2026 | 91.3% | 126 |
| 28 Apr 2026 | 91.3% | 126 |
| 21 Apr 2026 | 89.9% | 124 |
| 14 Apr 2026 | 90.6% | 125 |
| 7 Apr 2026 | 89.9% | 124 |
| 31 Mar 2026 | 89.9% | 124 |
| 24 Mar 2026 | 89.9% | 124 |
Frequently asked questions
What is the current water level of San Juan?
As of June 9, 2026, San Juan is at 89.9% of its capacity, holding approximately 124 hm³ of water, according to MITECO data.
Is San Juan reservoir full?
No. As of June 9, 2026, San Juan is high at 89.9% of its capacity, so it is not full.
Is the water level at San Juan rising or falling?
The level at San Juan is falling — it dropped 2.1 percentage points over the latest week on record.
How much water can San Juan hold?
San Juan has a total capacity of 138 hm³, of which about 124 hm³ is usable storage.
Where is San Juan reservoir located?
San Juan is located in Community of Madrid, Spain, within the Tajo basin (coordinates 40.377°N, 4.320°W).
What is San Juan used for?
San Juan is used primarily for multiple purposes, and is managed by CHT.