We are offering $aggregate principal amount of% Senior Notes due(the “Notes”). We will pay interest onthe Notes onandof each year, beginning, 2025. The Notes will mature on, We may redeem some or all of the Notes at any time at the applicable redemption price described in this prospectus supplement.We also have the right to redeem all of the Notes if, at any time, certain changes in law require us to make additional payments withrespect to taxes withheld from payments on the Notes. See “Description of Notes — Optional Redemption.” If a change of control triggering event as described in this prospectus supplement occurs, we will be required, subject to certainexceptions, to make an offer to each holder of Notes to purchase all or any part of that holder’s Notes for cash at a purchase priceequal to 101% of the principal amount of the Notes to be purchased, plus accrued and unpaid interest, if any, on those Notes to, butexcluding, the purchase date. See “Description of Notes — Change of Control Triggering Event.” The Notes will be our senior, unsecured obligations and will rank equally in right of payment with all of our existing and futuresenior, unsecured indebtedness and will rank senior in right of payment to any future indebtedness that we incur that is expresslysubordinated to the Notes. The Notes will be effectively subordinated to any future secured indebtedness that we incur to the extentof the value of the collateral securing such indebtedness. In addition, the Notes will be structurally subordinated to all existing and Investing in the Notes involves risks. You should read carefully the entire accompanying base prospectus and this prospectussupplement and the documents incorporated by reference herein and therein, including the section entitled “Risk Factors” beginning onpageS-8of this prospectus supplement. Neither the United States Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthese securities or determined if this prospectus supplement or the accompanying base prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. The Notes will be ready for delivery in book-entry form only through the facilities of The Depository Trust Company (“DTC”)for the accounts of its participants, including Euroclear Bank S.A./N.V., as operator of the Euroclear System, and ClearstreamBanking,société anonyme, on or about, 2025. BofA Securities Truist Securities This document is in two parts. The first part is this prospectus supplement, which describes the specificterms of this offering of Notes. The second part is the accompanying base prospectus, which gives moregeneral information, some of which may not apply to this offering of Notes. Generally, when we refer onlyto the “prospectus,” we are referring to both parts combined. If the information about the Notes offering It is important for you to read and consider all information contained in this prospectus supplement andthe accompanying base prospectus in making your investment decision. You should also read and considerthe information contained in the documents identified under the heading “Incorporation of Certain We have not, and the underwriters have not, authorized any dealer or other person to give any informationor to make any representation other than those contained or incorporated by reference in this prospectus supplement and the accompanying base prospectus. This prospectus supplement and the accompanying baseprospectus do not constitute an offer to sell or the solicitation of an offer to buy any securities other than theregistered securities to which they relate, nor does this prospectus supplement or the accompanying baseprospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to anyperson to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that Delivery of the Notes is expected to be made against payment for the Notes on, 2025, which will bethe fifth business day following the date hereof (this settlement cycle being referred to as “T+5”). UnderRule15c6-1 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), trades in the secondarymarket generally are required to settle in one business day, unless the parties to any such trade expressly agree Unless otherwise indicated or unless the context requires otherwise, all references in this prospectus to“we,” “us,” “our,” or the “Company” mean Waste Connections, Inc., a corporation under the laws ofOntario, Canada, and our consolidated subsidiaries, except where it is made clear that the terms mean Waste The reporting currency of the Company is the U.S. dollar. The Company’s consolidated Canadian dollarfinancial position is translated to U.S. dollars by applying the foreign currency exchange rate in effect at the Trademarks, Service Marks and Trade Names We own or have rights to various