Form of Proxy

Share Issuance Proposal: Approval of the issuance by American Water Works Company, Inc. (American Water) of shares of American Water common stock, par value $0.01 per share, pursuant to the Agreement and Plan of Merger, dated as of October 26, 2025, by and among American Water, Alpha Merger Sub, Inc., and Essential Utilities, Inc., and as it may be amended, restated, or otherwise modified from time to time.

American Water Adjournment Proposal: If presented at the Special Meeting, approval of the adjournment or postponement of the Special Meeting from time to time, if necessary or appropriate, to solicit additional proxies in the event there are not sufficient votes at the time of the Special Meeting (or any adjournment or postponement thereof) to approve the share issuance proposal, or to ensure that any supplement or amendment to the accompanying Joint Proxy Statement/Prospectus is timely provided to shareholders of American Water.