Okla. Stat. tit. 11 § 37-204
The public water distribution system shall consist only of the main lines of conveyance from the sources of supply, and the main lines for general distribution, including such other property as may be necessary in connection therewith for the proper maintenance and use of the water distribution system throughout the municipality.
The public distribution lines shall be established along the principal courses of distribution, or of supply, at such points, to such extent, of such dimensions and under such regulations as may be provided by the governing body; and these principal lines of distribution may be extensions or branches of lines already constructed or entirely new throughout as may be deemed expedient and necessary by the municipal governing body.
Okla. Stat. tit. 11, § 37-204