It was built in 1979 with the construction of the earth-fill Soulajule Dam along Arroyo Sausal, a tributary of Walker Creek.

The land upon which Soulajule Reservoir is built was purchased January 1, 1979 for $1,648,224.

[1][2] The Marin Municipal Water District is currently working on an electrification project for the Soulajule Reservoir pump station, that could pump water to Nicasio Reservoir without requiring the water district to rent a generator.

In 2017–2018, Marin County approved a $124,000 phase III to develop a plan to manage the mercury levels.

[5] Soulajule Reservoir is open to the public 7 days a week from sunrise to sunset.