United States securities and exchange commission logo September 1, 2021 John D. Schmitz Chief Executive Officer Select Energy Services, Inc. 1233 W. Loop South, Suite 1400 Houston, TX 77027 Re: Select Energy Services, Inc. Registration Statement on Form S-1 Filed August 26, 2021 File No. 333-259083 Dear Mr. Schmitz: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Liz Packebusch, Staff Attorney, at (202) 551-8749 with any questions. Sincerely, Division of Corporation Finance Office of Energy & Transportation cc: Stephen M. Gill