Groundwater first began writing fiction in the fifth grade, and in high school took an independent study in English. She went to the College of William and Mary and earned a degree in Psychology and Computer Science in 1978. She worked as a software engineer until 1999, then deciding to become a writer.

After attending multiple writers' conventions, she began writing short stories. Seven were published before she met a literary agent who agreed to publish her first novel, A Real Basket Case. It was published in 2007, and was nominated for the Best First Novel Agatha Award in 2007. Of her short stories, eight have been published including one translated into Persian. Another of Groundwater's short stories has been adapted into a live theater performance.

Groundwater's literary works have won multiple awards. Her first (and so far only) novel was nominated for the Best First Novel Agatha Award in 2007. Groundwater's short stories have won several contests. Her short story "New Zealand" won first place in the 2003 PPW Paul Gillette Memorial Writing Contest, and was the winner of the Rocky Mountain Fiction Writers Short Story Anthology Contest. "Flamingo Fatality" won the Great Manhattan Mystery Conclave Short Story Anthology Contest in 2005, and her 2005 short story "Lucky Bear" placed first in the Storyteller Magazine Flash Fiction Contest.