[6] The water howellia is found in large area of the Pacific Northwest region of the United States.

[7] The plant grows in wetland habitat surrounded by forests, which provide organic material.

[5] Associated tree species include Populus trichocarpa (California poplar), P. tremuloides (quaking aspen), and Fraxinus latifolia (Oregon ash).

[5] Seeds are produced in the water but they require open air for germination, so they sprout when the wetland has dried in the fall.

[5] Threats to this species include loss of habitat to logging and draining and conversion to urban use, alteration of the local hydrology by placement of dams and dikes, deposition of silt, livestock activity, introduced species of plants, low genetic diversity, and climate change.