A synthetic urine solution and method of its manufacture are disclosed. The solution includes water having a pH between 3 and 10. The solution further includes creatinine and means for removing bacteria from the solution so as to control or eliminate sepsis of the urine solution, preferably through the use of biocide. The solution exhibits a specific gravity of from 1.005 g/cm.sup.3 to 1.025 g/cm.sup.3. Additional compounds may also be included to further enhance the aesthetics or apparent authenticity of the synthetic urine produced according to this invention.