| Business | Phone |
| All Metro Backflow Testing 13173 Sw Bouneff St, Portland 97223 | (503) 579-0923 |
| Water Metrics Co West 400 Ne 97th Ave, Portland 97220 | (503) 255-4378 |
| Aqua Tech Backflow Svc 14655 Ne Russell Ct, Portland 97230 | (503) 251-1683 |
| Sentry Backflow Testing 10595 Se Hillcrest Dr, Portland 97266 | (503) 936-1170 |
| Clearwater Backflow 7170 E Burnside St, Portland 97215 | (503) 703-7821 |
| Columbia Cross Connection Cntr Portland 97214 | (503) 235-6141 |
| Guy Tyler Backflow Po Box 82164, Portland 97282 | (503) 998-7607 |