| Exhibit Number | | | | | | Exhibit Description | | |
| 3.1 | | | | | | Restated Certificate of Incorporation of American Water Works Company, Inc. (incorporated by reference to Exhibit 3.1 to American Water Works Company, Inc.’s Quarterly Report on Form 10-Q, File No. 001-34028, filed November 6, 2008). | | |
| 3.2 | | | | | | Amended and Restated Bylaws of American Water Works Company, Inc. (incorporated by reference to Exhibit 3.1 to the Company’s Current Report on Form 8-K, File No. 001-34028, filed December 8, 2022). | | |
| 4.1 | | | | | | Indenture, dated as of June 29, 2023, among American Water Capital Corp., American Water Works Company, Inc. and U.S. Bank Trust Company, National Association (incorporated by reference to Exhibit 4.1 to the Company’s Current Report on Form 8-K, File No. 001-34028, filed June 29, 2023). | | |
| *10.1 | | | | | | Extension Agreement, dated as of October 26, 2023, by and among American Water Works Company, Inc., American Water Capital Corp., each of the Lenders party thereto, and Wells Fargo Bank, National Association, as administrative agent. | | |
| *31.1 | | | | | | Certification of M. Susan Hardwick, President and Chief Executive Officer, pursuant to Section 302 of the Sarbanes-Oxley Act. | | |
| *31.2 | | | | | | Certification of John C. Griffith, Executive Vice President and Chief Financial Officer, pursuant to Section 302 of the Sarbanes-Oxley Act. | | |
| **32.1 | | | | | | Certification of M. Susan Hardwick, President and Chief Executive Officer, pursuant to Section 906 of the Sarbanes-Oxley Act. | | |
| **32.2 | | | | | | Certification of John C. Griffith, Executive Vice President and Chief Financial Officer, pursuant to Section 906 of the Sarbanes-Oxley Act. | | |
| 101.INS | | | | | | XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document. | | |
| 101.SCH | | | | | | Inline XBRL Taxonomy Extension Schema Document. | | |
| 101.CAL | | | | | | Inline XBRL Taxonomy Extension Calculation Linkbase Document. | | |
| 101.DEF | | | | | | Inline XBRL Taxonomy Extension Definition Linkbase Document. | | |
| 101.LAB | | | | | | Inline XBRL Taxonomy Extension Label Linkbase Document. | | |
| 101.PRE | | | | | | Inline XBRL Taxonomy Extension Presentation Linkbase Document. | | |
| 104 | | | | | | Cover Page Interactive Data File (formatted as Inline XBRL with applicable taxonomy extension information contained in Exhibits 101). | | |