Payment shall be on a unit price basis in accordance with the values submitted on the bid form. Contractor will submit monthly invoices for progress payments. A tenpercent (10%) retainage will be held out on each billing until all work is completed in accordance with the contract. Submitted invoices shall bear resemblance and Contain the information shown on the sample invoice form contained herein as exhibit m. The owner, upon approval of monthly progress, will certify invoices within five (5) Days for payment. Owner will pay certified billing within thirty (30) days to the contractor. Final payment will be made within thirty (30) days of approval of final Billing. Acceptance of completion on this project is based solely on the contractor achieving and maintaining the dewatering ditch(s) denoted on the drawings. Insurance and bond: during the performance of the work hereunder, contractor shall take out, carry and maintain, in insurance company or companies, and in policies of insurance acceptable to owner as specified in exhibit j of these bid documents. Each bid must include a bid bond equal to five percent (5%) of the amount of the bid. Bid Bonds of unsuccessful bidders will be returned. Each bid must be accompanied by a bid bond (exhibit d) payable to the owner for five Percent (5%) of the total amount of the bid. As soon as the bid prices have been compared, the owner will return the bonds of all except the three lowest responsible Bidders. When the contract is executed, the bonds of the two remaining unsuccessful bidders will be returned. The bid bond of the successful bidder will be retained until The payment bond (exhibit e) and performance bond (exhibit f) have been executed and approved, after which it will be returned. A certified check or cashiers check, Drawn on a bank that is a member of the federal reserve system, may be used in lieu of the bonds. Sureties companies executing bid, performance and payment bonds Required within the contract documents must appear on the treasury departments most current circular as a company holding a certificate of authority as acceptable sureties on federal bonds and as acceptable reinsurance companies (department circular 570, 2007 revision or any subsequent or newer revision thereof in effect prior to the date of the submission of a bid Hereunder). Such surety companies shall also be authorized to transact business in the state of texas. A performance bond and payment bond, each in the amount of one hundred percent The OWNER reserves the right to reject any or all BIDS and to waive formalities in BIDDING. In case of ambiguity or lack of clearness in stating the price in any BID, the OWNER reserves the right to consider the most advantageous BID thereof, or reject the BID.