Breitenauer See, Reservoir and bathing lake in Heilbronn district, Germany

Breitenauer See is a reservoir and bathing lake in the Sulm valley on the territory of Obersulm and Löwenstein in the Heilbronn district. The lake covers 40 hectares, is 1,500 metres long and 200 to 500 metres wide, and its dam is 425 metres long and 21 metres high. A roughly 400-metre-long marked bathing bay with about 10 hectares of lawn lies on its shore.

The lake was built between 1975 and 1980 by the Wasserverband Sulm, founded in 1973, after severe flood damage in the 1960s and 1970s, to protect Neckarsulm and its industrial areas. It was named after the nearby Breitenauer Hof and opened to the public in 1986. It was fully drained in winter 1995/1996 and again from December 2020 for safety inspections, refilling until spring 2023.

The lake serves as a gathering place for locals during warmer months, where people enjoy swimming, picnicking, and spending time with family and friends. It has become central to how residents spend their leisure time throughout the year.

The bathing bay is a marked-off stretch of about 400 metres with roughly 10 hectares of lawn for sunbathing. Boats, sailing and surfing have their own areas, and angling is possible; the fishing club stocks the lake. Around the water, 60 kilometres of signposted walking and cycling routes lead through the upper Sulm valley.

A nature trail winds through the surrounding area, explaining the fish species that inhabit the lake while passing through vineyards. This path offers visitors an educational walk that connects swimming with learning about the local wildlife.