| Business | Phone |
| Onawa Maintenance Bldg 1514 6th St, Onawa 51040 | (712) 433-1236 |
| Onawa City Clerk's Office 914 Diamond St, Onawa 51040 | (712) 433-1181 |
| Onawa City Community Ctr 320 10th St, Onawa 51040 | (712) 433-2201 |
| Onawa Power Plant 1035 8th St, Onawa 51040 | (712) 433-9606 |
| Onawa Sewage Lift Station S 6th St, Onawa 51040 | (712) 433-2674 |
| Onawa Superintendent's Office 1514 6th St, Onawa 51040 | (712) 433-1511 |