Exhibit 21.1

LIST OF SUBSIDIARIES

The following entities were subsidiaries of the Registrant as of May 14, 2026. Pursuant to Item 601(b)(21)(ii) of Regulation S-K, certain subsidiaries of the Registrant which, considered in the aggregate as a single subsidiary, would not have constituted a significant subsidiary (as defined in Rule 1-02(w) of Regulation S-X) have been omitted.

Name						Jurisdiction of Incorporation or Organization
ADS Ventures, Inc.						Delaware
StormTech LLC						Delaware
ADS Worldwide, Inc.						Delaware
ADS Europe Holding B.V.						Netherlands
ADS Europe B.V.						Netherlands
ADS Middle East FZE						United Arab Emirates
ADS International, Inc.						Delaware
ADS Mexicana, S.A. de C.V.(1)						Mexico
ADSM Centro América, S.A.						Costa Rica
CEDEIM Centro de Desarrollo, Educación e Investigación de México, S.A. de C.V.						Mexico
ADSI-1, LLC						Delaware
Teco S.r.l						Italy
Fish Water Products Sdn. Bhd.						Malaysia
ADSI-2, LLC						Delaware
Teco Irrigation USA, Inc.						California
Kimplas Piping Systems Private Limited(2)						India
Kimplas Limited						England and Wales
Hancor of Canada, Inc.						Canada
Tubos y Plásticos ADS Chile Limitada(3)						Chile
Tuberias Tigre-ADS Limitada(4)						Chile
Tigre-ADS Argentina S.R.L.(5)						Argentina
Tigre-ADS Colombia Limitada(5)						Colombia
Tigre-ADS Peru S.A.C.(5)						Peru
Tubos Tigre-ADS do Brasil Limitada(5)						Brazil
Tubos y Plásticos Tigre-ADS de Chile Limitada(5)						Chile
ADS Strategic Services LLC						Delaware
EQ Truepointe One, LLC(6)						Ohio
Green Line Polymers, LLC						Delaware
The Traylor Group, Inc.						Alabama
JET Polymer Recycling, LLC						Alabama
Infiltrator Water Technologies, LLC						Delaware
Delta Treatment Systems, LLC						Delaware
Ezflow GP, LLC						Delaware
Ezflow, L.P.(7)						Tennessee
Orenco Systems, Inc.						Oregon
Presby Environmental Holdings, LLC						Delaware
Presby Environmental, Inc.						New Hampshire
Presby Plastics, Inc.						New Hampshire
National Diversified Sales, Inc.						California

(1) Owned 51% by ADS Worldwide, Inc. and 49% by our joint venture partner.

(2) Owned 99.9999% by ADSI-1, LLC and nominal interests are held by ADSI-2, LLC.

(3) Owned 86.6354% by ADS Worldwide, Inc. and 13.3646% by ADS International, Inc.

(4) Owned 50% by Tubos y Plásticos ADS Chile Limitada and the remaining 50% by our joint venture partner.

(5) Nominal interests are held by Tuberias Tigre-ADS Limitada and our joint venture partner.

(6) Owned 62.69% by Advanced Drainage Systems, Inc.

(7) Owned 99.99% by Infiltrator Water Technologies, LLC and 0.01% by EZflow GP, LLC.

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