ADVANCED DRAINAGE SYSTEMS, INC.

Item 1.01 Entry Into a Material Definitive Agreement. On November 6, 2026, the Company entered into a Fifth Amendment to Credit Agreement and First Amendment to Guarantee and Collateral Agreement (the “Fifth Amendment”) which amends (i) the Company’s Credit Agreement dated as of July 31, 2019 (as amended by the First Amendment to Credit Agreement, dated as of September 24, 2019, the Second Amendment to Credit Agreement, dated as of May 26, 2022, the Third Amendment to Credit Agreement, dated as of November 26, 2025, the Fourth Amendment to Credit Agreement, dated as of February 27, 2026 and as further amended, restated, amended and restated, supplemented or otherwise modified prior to the date hereof the “Existing Credit Agreement”, and as amended by the Fifth Amendment, the “Credit Agreement”), and (ii) the Company’s Guarantee and Collateral Agreement, dated as of July 31, 2019 (the “Existing Guarantee and Collateral Agreement”). The Fifth Amendment was entered into by the Company and the subsidiary guarantors party thereto, Bank of America, N.A., as administrative agent under the Term Facility and PNC Bank, National Association, as administrative agent under the Revolving Facility and as administrative agent for the Secured Parties (as defined in the Credit Agreement) and the several financial institutions or entities party thereto as lenders. The obligations of the Company under the Credit Agreement are guaranteed by certain of the Company’s subsidiaries, including Infiltrator Water Technologies, LLC, StormTech LLC and Orenco, Inc. (the “Guarantors”) and the Guarantors secure the obligations thereunder by granting a first priority lien in substantially all of such Guarantor’s assets (subject to certain exceptions and limitations). Among other things, the Fifth Amendment (i) increased the aggregate revolving commitments under the Existing Credit Agreement by $300.0 million, resulting in total revolving commitments of $1.05 billion, through an incremental revolving commitment incurred pursuant to the Existing Credit Agreement, (ii) added provisions to permit supply chain financing and receivables financing arrangements, and (iii) amended certain related provisions of the Existing Guarantee and Collateral Agreement in connection with such supply chain financing and receivables financing arrangements. The Fifth Amendment includes customary representations, warranties, covenants and events of default. Capitalized terms used but not defined herein have the meaning given to such terms in the Credit Agreement. The foregoing description of the Fifth Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Fifth Amendment and the Credit Agreement, a copy of which is filed as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated herein by reference.