NAICS 221310

Overview

The North American Industry Classification System (NAICS) is the federal standard for classifying business establishments to produce consistent statistics about the U.S. economy. Created under the Office of Management and Budget (OMB) and adopted in 1997, it was developed jointly by the Economic Classification Policy Committee (ECPC) with Statistics Canada and Mexico’s INEGI. The current classification vintage is 2022. ¹

NAICS 221310 covers establishments primarily engaged in operating water treatment plants and/or operating water supply systems. Systems may include pumping stations, aqueducts, and distribution mains, and the water may be delivered for drinking, irrigation, or other uses. Both government and private establishments are classified here when they operate such systems. ²

See also on G2X:

• G2X — NAICS 221310 overview: https://app.g2xchange.com/naics/221310
• G2X — NAICS 221320 overview: https://app.g2xchange.com/naics/221320
• G2X — PSC S114 Utilities—Water: https://app.g2xchange.com/psc/S114

What this NAICS covers

• Operation of water treatment plants that purify or otherwise treat water. ²
• Operation of complete water supply systems serving end users. ²
• Management of water system components such as pumping stations. ²
• Operation of water conveyance assets, including aqueducts. ²
• Operation of distribution mains that deliver water to customers. ²
• Provision of potable water for drinking purposes via utility systems. ²
• Provision of water for irrigation or other non-potable uses via utility systems. ²

Related NAICS and PSC codes

Type	Code	Descriptor
NAICS	221320	Sewage Treatment Facilities (closely related industry group). 2
NAICS	56221	Waste Treatment and Disposal (distinct from sewer/sewage facilities). 2
PSC	S114	Utilities—Water (service purchases aligned to water utility supply). 6
PSC	4610	Water Purification Equipment (products often procured for water systems). 6

Industry boundaries and exclusions

• Establishments operating waste treatment or disposal facilities (other than sewer/sewage treatment) are classified in 56221, not in 221310. ²
• Government units administering environmental or utility programs (e.g., sanitation districts) are classified to public administration, such as 926130, whereas government entities that operate water/irrigation systems fall under 221310. ⁵

Placement within the NAICS hierarchy

NAICS groups industries by similarity in production processes. Water utilities are part of the Utilities sector; Water Supply and Irrigation Systems is a national industry within the “Water, Sewage, and Other Systems” industry group. NAICS uses a 2- to 6-digit hierarchical structure: sector, subsector, industry group, industry, and national industry. ³

Frequently asked questions

• What activities fall under NAICS 221310?

  • Establishments in this industry operate water treatment plants and/or water supply systems, including related assets such as pumping stations, aqueducts, and distribution mains. Service may include potable supply for drinking as well as irrigation and other non-potable uses, when delivered through utility systems. ²

• Are municipal utilities and irrigation districts included?

  • Yes. Government-run utilities that operate water or irrigation systems are classified in 221310. Government units primarily administering programs or regulation (e.g., sanitation district administration) are classified in public administration, such as 926130, rather than in the Utilities sector. ⁵

• How does NAICS 221310 differ from 221320?

  • 221310 covers operating water supply and irrigation systems. 221320 covers operating sewer systems or sewage treatment facilities that collect, treat, and dispose of waste. They are separate industries within Utilities with distinct processes and outputs. ²

• Which PSCs commonly appear with 221310 awards?

  • Utility service buys often use S114. Related product purchases can include equipment under 4610 Water Purification Equipment and 4620 Water Distillation Equipment, depending on the requirement’s scope and whether goods or services are being procured. ⁶

• What NAICS vintage applies today?

  • Federal statistical programs are transitioning to the 2022 NAICS. The Census Bureau’s implementation plan indicates programs will adopt the 2022 structure by the end of calendar year 2027, consistent with NAICS’s five-year revision cycle. ⁴

Useful resources

• G2X — NAICS 221310 overview: https://app.g2xchange.com/naics/221310
• U.S. Census Bureau — NAICS Codes & Understanding Industry Classification Systems (2022 guidance). ³
• U.S. Census Bureau — Sector 22 definitions (includes 221310 industry description). ²
• U.S. Census Bureau — Implementation of the 2022 NAICS (timeline and program adoption). ⁴
• Acquisition.gov — Product and Service Code (PSC) Manual (service/product codes such as S114, 4610). ⁶

References

1. U.S. Census Bureau — Classifying Businesses: NAICS adoption and development history (OMB/ECPC; joint with Canada and Mexico). https://www.census.gov/about/history/historical-censuses-and-surveys/census-programs-surveys/economic/classifying-businesses.html
2. U.S. Census Bureau — Sector 22 Utilities archive: industry description for NAICS 221310 and cross-references. https://www.census.gov/naics/resources/archives/sect22.html
3. U.S. Census Bureau — Economic Census 2022 Guidance: NAICS Codes & Understanding Industry Classification Systems. https://www.census.gov/programs-surveys/economic-census/year/2022/guidance/understanding-naics.html
4. U.S. Census Bureau — Implementation of the 2022 NAICS (definition, five-year revisions, adoption timeline). https://www.census.gov/library/reference/code-lists/naics/2022/implementation-timeline.html
5. U.S. Census Bureau — Sector 92 cross-references: government administration vs. operating water/irrigation systems. https://www.census.gov/naics/resources/archives/sect92.html
6. Acquisition.gov — Product and Service Code Manual (October 2021), showing S114 Utilities—Water and relevant product groups (4610, 4620). https://www.acquisition.gov/sites/default/files/manual/October%202021%20PSC%20Manual.pdf