P.R. Laws tit. 12, § 745
Except in the cases of §§ 742 and 743 of this title, no one shall construct a building or bridge over a ditch or aqueduct belonging to another, nor take any water therefrom, nor utilize the products thereof or of its margins, nor the power of its current, without the express consent of the owner.
Nor may the owners of the estates crossed by a ditch, or aqueduct or along the boundaries of which it runs, allege any right of possession to the use of its channel or margins, unless it be based on titles of ownership carrying such right. If on account of its immemorial construction, or for any other cause, the width of the channel of an aqueduct should not be exactly determined, it shall be fixed in accordance with the provisions of § 737 of this title when there are not ancient remains or vestiges establishing it.
The provisions of municipal ordinances shall be observed with regard to irrigation communities as to the use of their currents and of their channels and margins.
History —Law of Waters, art 99.