| Naics index | Naics index description |
|---|---|
| 221310 | Water treatment and distribution |
| 221310 | Water treatment plants |
| 221320 | Collection, treatment, and disposal of waste through a sewer system |
| 221320 | Sewage disposal plants |
| 221320 | Sewage treatment plants or facilities |
| 221320 | Sewer systems |
| 221320 | Waste collection, treatment, and disposal through a sewer system |
| 221330 | Steam production and distribution |
| 221330 | Air-conditioning supply |
| 221330 | Cooled air distribution |