Onawa City Of--water Dept 1035 8th St Onawa, IA 51040 Phone : (712) 433-1231 Business Category Government Offices-City Village & Twp Government Offices State & Local Government Offices & Public Schools Onawa Water Department 900 8th St Onawa, IA 51040 Phone : (712) 433-1231 Business Category Water & Sewage Companies-Utility Water Supply Regulation & Admin Of Communications Electric Gas & Other Utilities