Form: 10-K

Annual report [Section 13 and 15(d), not S-K Item 405]

February 18, 2026

Exhibit 21.1

Subsidiaries of Select Water Solutions, Inc.

Entity

  ​ ​ ​

State of Formation

1960 Well Services, LLC

Ohio

Affirm Oilfield Services, LLC

Texas

Badlands Power Fuels, LLC

Delaware

Badlands Power Fuels, LLC

North Dakota

Big Spring Recycling System, LLC

Delaware

Blackjack Mineral Investments, LLC

Texas

Bobcat North Lima, LLC

Ohio

Breakwater Energy Partners, LLC

Texas

Breakwater Energy Services, LLC

Texas

Breakwater Midstream, LLC

Texas

Buckhorn Disposal ND, LLC

Delaware

Buckhorn Energy Oaks Disposal Services, LLC

Delaware

Clearwater Five, LLC

Ohio

Clearwater Solutions, LLC

Ohio

Clearwater Three, LLC

Ohio

Complete Energy Services, Inc.

Delaware

Crescent Companies, LLC

Delaware

Dishon Disposal, LLC

North Dakota

EnerMAX Services G.P. ULC

Alberta

EnerMAX Services Holdings, LLC

Delaware

EnerMAX Services Limited Partnership

Alberta

EnerMAX Services (U.S.) Inc.

Delaware

EWS #1 DJ Basin LLC

Delaware

EWS #8 DJ Basin LLC

Delaware

Guard Drilling Mud Disposal, LLC

Delaware

Heckmann Water Resources (CVR), Inc.

Delaware

Heckmann Water Resources (CVR), LLC

Delaware

Heckmann Water Resources, LLC

Delaware

Ideal Oilfield Disposal, LLC

North Dakota

Landtech Enterprises, L.L.C.

North Dakota

Mallard Midstream, LLC

Delaware

Navy Holdings, Inc.

Delaware

Navy Holdco, LLC

Delaware

New Heckmann Water Resources Corporation

Delaware

Nuverra Ohio Disposal LLC

Delaware

Nuverra Total Solutions, LLC

Delaware

Oaks’ Disposal Services, LLC

Montana

Peak Rentals, LLC

 

Texas

Quail Run Services, LLC

Texas

Rockwater Energy Solutions North Dakota, Inc.

Delaware

Rockwater Energy Solutions Water Management, LLC

Delaware

Rockwater Production Testing Ltd.

Alberta

Rockwater West TX, LLC

Delaware

Select Agua Libre Midstream, LLC

Delaware

Select Chemistry, LLC

 

Delaware

Select Energy Services, LLC

Texas

Select Energy Solutions (RW), Inc.

Delaware

Select Water Reuse, LLC

Delaware

Select Water Solutions, LLC

 

Delaware

SES Holdings, LLC

 

Delaware

SES Intermediate Holdings, LLC

Delaware

SES Sub A, LLC

Delaware

SES Sub B, LLC

Delaware


SES Sub C, LLC

Delaware

SWS ND, Inc.

Delaware

Trinity Acquisition, LLC

Delaware

Trinity Environmental Brokerage, L.L.C.

Delaware

Trinity Environmental Management, LLC

Delaware

Trinity Environmental Services I, L.L.C.

Delaware

Trinity Environmental SWD I, L.L.C.

Delaware