| Journeymen Plumbers Union Local #55 of the United Assoc Plumbers&pipefitter | Related tax-exempt org | Labor union services | OH | 340320390 |
| Plumbers Local Union #55 Supplemental Unemployment Benefit Fund | Related tax-exempt org | Supplemental unemployment benefits | OH | 341269418 |
| Access Plumbing LLC | Related partnership | — | — | — |
| Advanced Mechanical Contractors LLC | Related partnership | — | — | — |
| Cromwell Mechanical LLC | Related partnership | — | — | — |
| Next Generation Service LLC | Related partnership | — | — | — |
| Summit Plumbing Contractors | Related partnership | — | — | — |
| Synergy LLC Contractors | Related partnership | — | — | — |
| Xstream Plumbing LLC | Related partnership | — | — | — |
| Alcon Mechanical Piping | Related taxable corporation/trust | — | — | — |
| American Plumbing Contractors | Related taxable corporation/trust | — | — | — |
| Bican Plumbing | Related taxable corporation/trust | — | — | — |
| Cleveland Plumbers JATC | Related taxable corporation/trust | — | — | — |
| Commerce Plumbing Company | Related taxable corporation/trust | — | — | — |
| D & a Plumbing & Heating INC | Related taxable corporation/trust | — | — | — |
| EB KATZ Company | Related taxable corporation/trust | — | — | — |
| Formica Plumbing & Sewer CO | Related taxable corporation/trust | — | — | — |
| Gorman-Lavelle Corporation | Related taxable corporation/trust | — | — | — |
| Grand River Plumbing | Related taxable corporation/trust | — | — | — |
| Hammond Mechanical Corp | Related taxable corporation/trust | — | — | — |
| Jakobsky Plumbing & Heating | Related taxable corporation/trust | — | — | — |
| JOHN Prochazka Plumbing and Heating | Related taxable corporation/trust | — | — | — |
| K a Plumbing CO | Related taxable corporation/trust | — | — | — |
| Miller Plumbing & Heating Company | Related taxable corporation/trust | — | — | — |
| Neptune Plumbing & Heating CO | Related taxable corporation/trust | — | — | — |