San Juan
Community of Madrid · Tajo
Capacity
138 hm³
Coordinates
40.377°N, 4.320°W
Operator
CHT
82.6% full
Current fill
82.6%vs 7 days ago
-0.7%losing
vs 1 year ago
+4.3%year-over-year
7-day trend
→stable
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 July 27, 2026, San Juan is filled to 82.6% of its total capacity, holding roughly 114 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 held broadly steady (-0.7 pts), and it is 4.3 points above its level on the same date a year earlier.
Across the readings we hold for San Juan — 420 data points between July 17, 2018 and July 27, 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
- 82.6%
- Water stored
- 114 hm³
- Total capacity
- 138 hm³
- Usable capacity
- 124 hm³
- 7-day change
- ▼ 0.7 pts
- Year-on-year
- ▲ 4.3 pts
- Primary use
- Multipurpose
- River basin
- Tajo
- Operator
- CHT
- Coordinates
- 40.377°N, 4.320°W
- Last updated
- July 27, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 27 Jul 2026 | 82.6% | 114 |
| 20 Jul 2026 | 83.3% | 115 |
| 14 Jul 2026 | 86.2% | 119 |
| 7 Jul 2026 | 88.4% | 122 |
| 30 Jun 2026 | 89.9% | 124 |
| 23 Jun 2026 | 89.1% | 123 |
| 16 Jun 2026 | 88.4% | 122 |
| 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 |
Frequently asked questions
What is the current water level of San Juan?
As of July 27, 2026, San Juan is at 82.6% of its capacity, holding approximately 114 hm³ of water, according to embalses.net data.
Is San Juan reservoir full?
No. As of July 27, 2026, San Juan is high at 82.6% of its capacity, so it is not full.
Is the water level at San Juan rising or falling?
The level at San Juan has been broadly stable over the latest week on record (-0.7 points).
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.