It is the only reservoir in the Community of Madrid that legally permits motorized recreational boating.
The reservoir area contains the remains of the ancient Hermitage of the Virgin of the New, which was submerged during the construction of the dam and occasionally becomes visible when water levels are extremely low.
La Virgen de la Nueva beach was the first reservoir beach in Madrid to be awarded the prestigious Blue Flag certification for water quality and facilities.
The dam's construction was part of a major hydro-technical project to power the post-war industrialization of the Madrid region.
The reservoir covers three different municipalities: San Martín de Valdeiglesias, Pelayos de la Presa, and El Tiemblo.
Pantano de San Juan is the only reservoir in the Madrid region where motorized water sports, including jet skiing and water skiing, are permitted. Spanning over 14 kilometers, the reservoir holds the waters of the Alberche River and is surrounded by pine forests. It was created in 1955 to provide electricity and water supply to the capital. The shoreline features several designated recreational zones, including the popular La Virgen de la Nueva beach, which holds a Blue Flag status. The reservoir serves as a significant hub for sailing schools and rowing clubs in the community. It acts as a primary water source for the southwestern part of the Madrid metropolitan area. The surrounding landscape provides natural habitats for diverse bird species, including the Spanish imperial eagle.
The elevated cliffs overlooking the reservoir from the M-501 road access points.
Bring water shoes, as the shoreline is rocky and uneven in many areas.
Arrive early during summer weekends to secure parking, as spaces fill up rapidly.
Check local forestry regulations before planning any BBQ or picnic activities, as open fires are strictly prohibited during high-risk fire seasons.
Attempting to swim near the dam wall or near boat launching ramps, as these are high-traffic dangerous zones for watercraft.
Lifeguard services and water sport rentals are primarily operational from late spring through early autumn.
Respect noise ordinances, carry out all trash to keep the natural area clean, and strictly adhere to restricted swimming zones near the dam wall.
