The Utilities sector comprises establishments engaged in the provision of the following utility services: electric power, natural gas, steam supply, water supply, and sewage removal. Within this sector, the specific activities associated with the utility services provided vary by utility: electric power includes generation, transmission, and distribution; natural gas includes distribution; steam supply includes provision and/or distribution; water supply includes treatment and distribution; and sewage removal includes collection, treatment, and disposal of waste through sewer systems and sewage treatment facilities.
Excluded from this sector are establishments primarily engaged in waste management services classified in Subsector 562, Waste Management and Remediation Services. These establishments also collect, treat, and dispose of waste materials; however, they do not use sewer systems or sewage treatment facilities.
Utilities has a two-digit North American Industry Classification System (NAICS) code of 22. Its subcategories are as follows:
| NAICS Code | NAICS Title |
| 221 | Oil and Gas Extraction |
| 221111 | Hydroelectric Power Generation |
| 221112 | Fossil Fuel Electric Power Generation |
| 221113 | Nuclear Electric Power Generation |
| 221119 | Other Electric Power Generation |
| 221121 | Electric Bulk Power Transmission and Control |
| 221122 | Electric Power Distribution |
| 221210 | Natural Gas Distribution |
| 221310 | Water Supply and Irrigation Systems |
| 221320 | Sewage Treatment Facilities |
| 221330 | Steam and Air-Conditioning Supply |
