221310 — Water Supply and Irrigation Systems
Description
This industry comprises establishments primarily engaged in operating water treatment plants and/or operating water supply systems. The water supply system may include pumping stations, aqueducts, and/or distribution mains. The water may be used for drinking, irrigation, or other uses (as defined in the official U.S. Census Bureau 2022 NAICS Manual).
Exclusions & Cross-References
- Establishments primarily engaged in irrigation project construction (except lawn) are classified in Industry
- 237110, Water and Sewer Line and Related Structures Construction;
- Establishments primarily engaged in installing lawn sprinkler systems are classified in Industry 238220,
- Plumbing, Heating, and Air-Conditioning Contractors;
- Establishments primarily engaged in lawn irrigation services are classified in Industry 561730,
- Landscaping Services;
- Establishments primarily engaged in retailing bottled water are classified in U.S. Industry 445298, All
- Other Specialty Food Retailers; and
- Government establishments primarily engaged in administering irrigation districts are classified in Industry
- 926130, Regulation and Administration of Communications, Electric, Gas, and Other Utilities.
Overview Facts
Legacy SIC Concordance
Trace the historical mapping chain from the 1987 Standard Industrial Classification (SIC) to the modern 2022 NAICS code format.
- SIC 4941 - Water Supply (via SIC1987:4941→NAICS1997:22131→2002:221310→2007:221310→2012:221310→2017:221310→2022:221310)
- SIC 4971 - Irrigation Systems (via SIC1987:4971→NAICS1997:22131→2002:221310→2007:221310→2012:221310→2017:221310→2022:221310)
Suggested Product Service Codes (Advisory)
The following Product Service Codes (PSCs) are advisory suggestions aligned with this NAICS code. Note: NAICS and PSC codes map to different dimensions of procurement (industry vs. product/service). There is no official binding 1:1 crosswalk.
- PSC M1NE — OPERATION OF WATER SUPPLY FACILITIES
Source: DoD DPCAP PSC Selection Tool (Ingested: 2026-06-29)
Frequently Asked Questions (FAQ)
Is NAICS code 221310 valid in 2022? ▾
Yes, 221310 is a valid 6-digit 2022 NAICS national industry code representing 'Water Supply and Irrigation Systems' under Sector 22 in the official classification index.
What is the SBA size standard for NAICS code 221310? ▾
The Small Business Administration (SBA) has established a small business size standard of $41,000,000 for NAICS code 221310 (Water Supply and Irrigation Systems), calculated based on receipts.
What is the legacy SIC equivalent for NAICS 221310? ▾
According to official Census Bureau concordance tables, NAICS code 221310 (Water Supply and Irrigation Systems) maps to legacy 1987 Standard Industrial Classification (SIC) codes: 4941 - Water Supply, 4971 - Irrigation Systems.
Related Pages & Tools
Further regulatory reference links for NAICS code 221310:
- Sector 22 Directory Hub — List of related industries in the Utilities sector.
- SIC ↔ NAICS Crosswalk Tool — Look up mappings between legacy SIC codes and modern classifications.
- NAICS 221310 to SIC Crosswalk — Bidirectional mapping to legacy SIC codes (Water Supply and Irrigation Systems).
- SBA Size Standards Guide — Complete rules and averaging periods for small business classifications.
- Calculating Annual Receipts Guide — Detailed worked example of revenue calculation rules.
- IRS Principal Business Activity Guide — How NAICS codes map to corporate and entity tax filings.