((a)) ** Submission; contractual nature of approval by Administrator; agreement on eligible costs; single grant**

((1)) Each applicant for a grant shall submit to the Administrator for his approval, plans, specifications, and estimates for each proposed project for the construction of treatment works for which a grant is applied for under from funds allotted to the State under and which otherwise meets the requirements of this chapter. The Administrator shall act upon such plans, specifications, and estimates as soon as practicable after the same have been submitted, and his approval of any such plans, specifications, and estimates shall be deemed a contractual obligation of the United States for the payment of its proportional contribution to such project.

((2))

((A)) ** .—** Before taking final action on any plans, specifications, and estimates submitted under this subsection after the 60th day following , the Administrator shall enter into a written agreement with the applicant which establishes and specifies which items of the proposed project are eligible for Federal payments under this section. The Administrator may not later modify such eligibility determinations unless they are found to have been made in violation of applicable Federal statutes and regulations.

((B)) ** .—** Eligibility determinations under this paragraph shall not preclude the Administrator from auditing a project pursuant to , or other authority, or from withholding or recovering Federal funds for costs which are found to be unreasonable, unsupported by adequate documentation, or otherwise unallowable under applicable Federal cost principles, or which are incurred on a project which fails to meet the design specifications or effluent limitations contained in the grant agreement and permit pursuant to for such project.

((3)) In the case of a treatment works that has an estimated total cost of $8,000,000 or less (as determined by the Administrator), and the population of the applicant municipality is twenty-five thousand or less (according to the most recent United States census), upon completion of an approved facility plan, a single grant may be awarded for the combined Federal share of the cost of preparing construction plans and specifications, and the building and erection of the treatment works.

((b)) ** Periodic payments** The Administrator shall, from time to time as the work progresses, make payments to the recipient of a grant for costs of construction incurred on a project. These payments shall at no time exceed the Federal share of the cost of construction incurred to the date of the voucher covering such payment plus the Federal share of the value of the materials which have been stockpiled in the vicinity of such construction in conformity to plans and specifications for the project.

((c)) ** Final payments** After completion of a project and approval of the final voucher by the Administrator, he shall pay out of the appropriate sums the unpaid balance of the Federal share payable on account of such project.

((d)) ** Projects eligible** Nothing in this chapter shall be construed to require, or to authorize the Administrator to require, that grants under this chapter for construction of treatment works be made only for projects which are operable units usable for sewage collection, transportation, storage, waste treatment, or for similar purposes without additional construction.

((e)) ** Technical and legal assistance in administration and enforcement of contracts; intervention in civil actions** At the request of a grantee under this subchapter, the Administrator is authorized to provide technical and legal assistance in the administration and enforcement of any contract in connection with treatment works assisted under this subchapter, and to intervene in any civil action involving the enforcement of such a contract.

((f)) ** Design/build projects**

((1)) ** Agreement** Consistent with State law, an applicant who proposes to construct waste water treatment works may enter into an agreement with the Administrator under this subsection providing for the preparation of construction plans and specifications and the erection of such treatment works, in lieu of proceeding under the other provisions of this section.

((2)) ** Limitation on projects** Agreements under this subsection shall be limited to projects under an approved facility plan which projects are—

((A)) treatment works that have an estimated total cost of $8,000,000 or less; and

((B)) any of the following types of waste water treatment systems: aerated lagoons, trickling filters, stabilization ponds, land application systems, sand filters, and subsurface disposal systems.

((3)) ** Required terms** An agreement entered into under this subsection shall—

((A)) set forth an amount agreed to as the maximum Federal contribution to the project, based upon a competitively bid document of basic design data and applicable standard construction specifications and a determination of the federally eligible costs of the project at the applicable Federal share under ;

((B)) set forth dates for the start and completion of construction of the treatment works by the applicant and a schedule of payments of the Federal contribution to the project;

((C)) contain assurances by the applicant that (i) engineering and management assistance will be provided to manage the project; (ii) the proposed treatment works will be an operable unit and will meet all the requirements of this subchapter; and (iii) not later than 1 year after the date specified as the date of completion of construction of the treatment works, the treatment works will be operating so as to meet the requirements of any applicable permit for such treatment works under ;

((D)) require the applicant to obtain a bond from the contractor in an amount determined necessary by the Administrator to protect the Federal interest in the project; and

((E)) contain such other terms and conditions as are necessary to assure compliance with this subchapter (except as provided in paragraph (4) of this subsection).

((4)) ** Limitation on application** Subsections (a), (b), and (c) of this section shall not apply to grants made pursuant to this subsection.

((5)) ** Reservation to assure compliance** The Administrator shall reserve a portion of the grant to assure contract compliance until final project approval as defined by the Administrator. If the amount agreed to under paragraph (3)(A) exceeds the cost of designing and constructing the treatment works, the Administrator shall reallot the amount of the excess to the State in which such treatment works are located for the fiscal year in which such audit is completed.

((6)) ** Limitation on obligations** The Administrator shall not obligate more than 20 percent of the amount allotted to a State for a fiscal year under for grants pursuant to this subsection.section 1285 of this title

((7)) ** Allowance** The Administrator shall determine an allowance for facilities planning for projects constructed under this subsection in accordance with section 1281() of this title.l

((8)) ** Limitation on Federal contributions** In no event shall the Federal contribution for the cost of preparing construction plans and specifications and the building and erection of treatment works pursuant to this subsection exceed the amount agreed upon under paragraph (3).

((9)) ** Recovery action** In any case in which the recipient of a grant made pursuant to this subsection does not comply with the terms of the agreement entered into under paragraph (3), the Administrator is authorized to take such action as may be necessary to recover the amount of the Federal contribution to the project.

((10)) ** Prevention of double benefits** A recipient of a grant made pursuant to this subsection shall not be eligible for any other grants under this subchapter for the same project.