Exhibit

We hereby consent to the incorporation by reference in this Registration Statement on Form S-3 of American Water Works Company, Inc. of our reportdated February 20, 2018 relating to the financial statements and the effectiveness of internal control over financial reporting, which appears in American Water Works Company, Inc.'s Annual Report on Form 10‑K for the year ended December 31, 2017. We also consent to the reference to us under the heading “Experts” in such Registration Statement.