| 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). | | |
| *10.1 | | | | | | Form of American Water Works Company, Inc. 2017 Omnibus Equity Compensation Plan 2023 Restricted Stock Unit Grant. | | |
| *10.2 | | | | | | Form of American Water Works Company, Inc. 2017 Omnibus Equity Compensation Plan 2023 Restricted Stock Unit Grant (for CEO, CFO and COO). | | |
| *10.3 | | | | | | American Water Works Company, Inc. 2017 Omnibus Equity Compensation Plan 2023 Performance Stock Unit Grant Form A-1. | | |
| *10.4 | | | | | | American Water Works Company, Inc. 2017 Omnibus Equity Compensation Plan 2023 Performance Stock Unit Grant Form A-2 (for CEO, CFO and COO). | | |
| *10.5 | | | | | | American Water Works Company, Inc. 2017 Omnibus Equity Compensation Plan 2023 Performance Stock Unit Grant Form B-1. | | |
| *10.6 | | | | | | American Water Works Company, Inc. 2017 Omnibus Equity Compensation Plan 2023 Performance Stock Unit Grant Form B-2 (for CEO, CFO and COO). | | |
| *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). | | |