Form: S-1

General form of registration statement for all companies including face-amount certificate companies

January 24, 2018


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Exhibit 21.1

Subsidiaries of Select Energy Services, Inc.

Entity   State of Formation
SES Holdings, LLC   Delaware
Select Energy Services, LLC   Delaware
Peak Oilfield Services, LLC   Texas
Affirm Oilfield Services, LLC   Texas
Rockwater Energy Solutions, LLC   Delaware
Benchmark Energy Products, LLC   Texas
Reef Services, LLC   Delaware
Rockwater West TX, LLC   Delaware
Crescent Companies, LLC   Oklahoma



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Subsidiaries of Select Energy Services, Inc.