American Water Works Company Inc

Evaluation of Disclosure Controls and Procedures

American Water maintains disclosure controls and procedures that are designed to ensure that information required to be disclosed in its reports filed or submitted under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to management, including the Chief Executive Officer and the Chief Financial Officer, to allow timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objective.

The Company’s management, including the Chief Executive Officer and the Chief Financial Officer, conducted an evaluation of the effectiveness of its disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act) as of March 31, 2025.

Based on that evaluation, the Chief Executive Officer and the Chief Financial Officer have concluded that, as of March 31, 2025, the Company’s disclosure controls and procedures were effective at a reasonable level of assurance.

Changes in Internal Control over Financial Reporting

The Company concluded that there have been no changes in internal control over financial reporting that occurred during the three months ended March 31, 2025, that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.