The lake primarily functions as a water reservoir as well as for recreational activities such as boating and fishing.

The dam at Guajataca Lake experienced a structural failure on September 22, 2017, due to the hit from Hurricane Maria.

Its normal storage capacity is 34,050 acre-feet (42,000,000 cubic metres), and its drainage basin is 24.58 square miles (63.7 km2).

[14][15] The construction of the dam was authorized by act 63 of the Legislature of Puerto Rico, known as the "Isabela public irrigation law," approved April 19, 1919.

"[20] Rosselló ordered the Puerto Rico National Guard and the Police to help assist in the evacuation effort downstream.

[21] The dam lies across the Guajataca River to form a reservoir that can hold roughly 11 billion gallons of water.