[1] Lesions affecting sacral segments or peripheral autonomic fibres result in atonic bladder with loss of sphincteric coordination.

Anticholinergic side effects of certain medications (for example, certain antipsychotics and antidepressants) may cause urinary retention which may lead to overflow incontinence.

Also overflow incontinence can be from increased outlet resistance from advanced vaginal prolapse causing a "kink" in the urethra or after an anti-incontinence procedure which has overcorrected the problem.

[citation needed] The concept of overflow incontinence has been criticised, because it is difficult to define and because the definitions that have been proposed have little clinical significance.

[2] In 2017 the Quality Improvement and Patient Safety (QIPS) committee of the American Urological Association (AUA) published a definition of nonneurogenic chronic urinary retention as a post-void residual of greater than 300 mL that was measured at least twice and extended over a period at least six months.

Patients with this condition presenting additionally with hydronephrosis, stage 3 chronic kidney disease, or recurrent urinary tract infection or urosepsis were considered as high risk groups.