> Enrich.chat gives AI agents verified work emails and mobiles. To use it from an agent, read https://enrich.chat/agents.md . This is the Markdown version of https://enrich.chat/sic/1781/ # SIC code 1781: Water well drilling The companies classified under SIC 1781, where they are based, how big they are and how the code maps to NAICS. By Enrich.chat Editorial. Updated October 22, 2026. **Short answer:** SIC 1781 is the Standard Industrial Classification code for Water well drilling, in division C (Construction). The companies counted under it are mostly very small: 78% have 50 or fewer employees. ## What is SIC 1781? SIC 1781 is the Standard Industrial Classification code for Water well drilling. It sits in division C, Construction. The first two digits name the major group, and the last two narrow it to a single industry. Most of the companies counted also carry NAICS 237110 (91%). - 78% of the companies counted have 50 or fewer employees, and the middle one is in the 11 to 50 range. - The largest group is headquartered in the United States (91%). Within the US, California is the biggest state (17%). - Most were founded in the 2000s (27%), then the 2010s (24%). **Figure: How SIC 1781 is built.** The code 1781 split into its parts: major group 17, then industry group and industry. It sits in division C, Construction. *The four digits of SIC 1781.* ## Which companies are classified under SIC 1781? The biggest by headcount range include Scientific Drilling, Cascade Environmental, Aqua Drill International, Cyclone Drilling and Sdi Gas. Names link to a company profile where we have one. | Company | Headquarters | Employees | | --- | --- | --- | | Scientific Drilling | The Woodlands, TX | 1,001 to 5,000 | | Cascade Environmental | Bothell, WA | 1,001 to 5,000 | | Aqua Drill International | Dickinson, TX | 501 to 1,000 | | Cyclone Drilling | Gillette, WY | 501 to 1,000 | | Sdi Gas | Mt. Morris, PA | 501 to 1,000 | | Yellow Jacket Drilling Services | Phoenix, AZ | 201 to 500 | | Hydro Resources Holdings | Sugar Land, TX | 201 to 500 | | Citadel Drilling | Calgary, Canada | 51 to 200 | | Stellar Drilling Fluids | Houston, TX | 51 to 200 | | Crux Subsurface | Spokane Valley, WA | 51 to 200 | | H2o Incorporated | Lafayette, LA | 51 to 200 | | Holt Services | Edgewood, WA | 51 to 200 | | Baugrund Süd Gesellschaft Für Geothermie Mbh | Bad Wurzach, Germany | 51 to 200 | | Weisinger Incorporated | Conroe, TX | 51 to 200 | | Abc Liovin Drilling | Signal Hill, CA | 51 to 200 | | Centerline Drilling | Prineville, OR | 51 to 200 | | Envirolink | Raleigh, NC | 51 to 200 | | Legacy Drilling | Stillwater, OK | 51 to 200 | | Southwind Drilling | Ellinwood, KS | 51 to 200 | | Us Water Well | Fresno, CA | 51 to 200 | | Mg Servicos Manutencao Projetos E Obras | Camacari, Brazil | 51 to 200 | | Klear Bit Technologies | Bridgeport, TX | 11 to 50 | | Daystar Directional Drilling | Noblesville, IN | 11 to 50 | | Sinclair Well Products | Cerritos, CA | 11 to 50 | | Stewart Brothers Drilling | Milan, NM | 11 to 50 | The table shows the 25 biggest by headcount range, with ties broken by audience size. The charts and percentages below cover every company counted for this page, not just these 25, and companies with fewer than 11 employees are not counted. Headquarters is the location on each company's public profile. ## Where are SIC 1781 companies based? Within the United States, California (17%), Texas (16%) and Washington (9%) lead. **Figure: US headquarters of companies in SIC 1781, by state.** A tile map of the United States shaded by the share of counted US companies in SIC 1781 headquartered in each state. The largest are California 17%, Texas 16%, Washington 9%. *Share of counted US companies in SIC 1781 by headquarters state. The three largest states are outlined.* ## How big are the companies counted for SIC 1781? 78% of them have 50 or fewer employees, and the middle one is in the 11 to 50 range. Companies with fewer than 11 employees are not counted. **Figure: Size of companies in SIC 1781.** Seven columns for the share of counted companies in SIC 1781 in each employee range: 11 to 50 78%, 51 to 200 15%, 201 to 500 2%, 501 to 1,000 3%, 1,001 to 5,000 2%, 5,001 to 10,000 0%, 10,001+ 0%. *Share of counted companies in SIC 1781 in each employee range.* ## How SIC 1781 compares - 78% of companies in SIC 1781 have 50 or fewer employees, against 60% across all NAICS codes on this site. - Washington holds 9% of the US companies here, against 3% across all NAICS codes on this site. ## SIC 1781 and the NAICS system NAICS replaced SIC as the U.S. federal standard in 1997, but the two do not line up one to one. These are the NAICS codes seen most among the companies counted under SIC 1781. | Code | Title | Share of counted | | --- | --- | --- | | NAICS 237110 | Water and Sewer Line and Related Structures Construction | 91% | | [NAICS 238990](https://enrich.chat/naics/238990/) | All Other Specialty Trade Contractors | 3% | ## How do SIC 1781 companies describe themselves? A code is assigned by classification, and a company does not choose its own, so the label a company uses for itself can differ. The most common labels here are Construction (49%), Oil and Gas (23%) and Environmental Services (9%). **Figure: How companies in SIC 1781 describe themselves.** Bars for the share of counted companies in SIC 1781 that give each industry on their public profile: Construction 49%, Oil and Gas 23%, Environmental Services 9%, Utilities 8%, Civil Engineering 4%. *Share of counted companies in SIC 1781 by the industry they list on their public profile.* ## Where SIC codes come from SIC was created in the 1930s and is now historical: the U.S. government replaced it with NAICS in 1997. It is still widely used, and the SEC still assigns a SIC code to every company that files on EDGAR. The full list is in the [SIC manual](https://www.osha.gov/data/sic-manual) that OSHA hosts, and the Census Bureau's [guide to understanding NAICS](https://www.census.gov/programs-surveys/economic-census/year/2022/guidance/understanding-naics.html) explains how the two relate. ## How do you reach the people at SIC 1781 companies? The people to talk to are usually operations and procurement leaders. You can build the list in three prompts to your AI agent. ### 1. Count them (free) Counting who matches never uses credits. ```text Use www.enrich.chat to count the companies with SIC code 1781 (Water well drilling) ``` ### 2. Find the people (5 credits per person) Name the roles you sell to. Each person returned is 5 credits, and name, title and company are included. ```text Use www.enrich.chat to find the operations and procurement leaders at companies with SIC code 1781, with their titles ``` ### 3. Get their work emails (10 credits each) An email is 10 credits only when one is found. Every email comes with a status: verified, catch-all or unknown. ```text Use www.enrich.chat to find the work emails for these people and tell me which ones are verified ``` ## More to explore Other SIC codes in major group 17: [SIC 1794: Excavation contractor](https://enrich.chat/sic/1794/) ## Frequently asked questions ### What is SIC code 1781? SIC 1781 is the code for Water well drilling, in division C (Construction). ### What is the NAICS code for SIC 1781 (Water well drilling)? 91% of the companies counted carry NAICS 237110 (Water and Sewer Line and Related Structures Construction), but the two systems do not map one to one. ### Which companies are classified under SIC 1781? The biggest by headcount range include Scientific Drilling, Cascade Environmental, Aqua Drill International, Cyclone Drilling and Sdi Gas. The page lists 25 with links to their profiles where we have them. ### How big are the companies in SIC 1781? 78% have 50 or fewer employees, and the middle one is in the 11 to 50 range. Companies with fewer than 11 employees are not counted. ### Is SIC still used? Yes. The U.S. government replaced SIC with NAICS in 1997, but SIC codes are still common in business databases, and the SEC still uses them on EDGAR. ## Try this prompt Find the people at SIC 1781 companies ```text Use www.enrich.chat to find the operations and procurement leaders at companies with SIC code 1781, with titles and verified work emails ``` ## Related - [Companies using a technology](https://enrich.chat/companies-using/) - [SIC 1794](https://enrich.chat/sic/1794/) - [Tech stack lookup](https://enrich.chat/tools/tech-stack-lookup/)