[ULPIANUS libro quinquagensimo tertio ad edictum. ] §39.3.10.prSi autem plures sint eiusdem loci domini, unde aqua ducitur, omnium uoluntatem esse sequendam non ambigitur: iniquum enim uisum est uoluntatem unius ex modica forte portiuncula domini praeiudicium sociis facere. §39.3.10.1An tamen subsequi uoluntas possit, uideamus.
[ULPIANUS libro quinquagensimo tertio ad edictum.]\n\nBut if there are several owners of the same estate from which water is drawn, there is no doubt that the consent of all must be followed; for it has seemed unjust that the consent of a single owner, perhaps with a very small share, should prejudice his co-owners.\n\nLet us see, however, whether consent can be given subsequently.
et placet nihil interesse, utrum praecedat uoluntas aquae ductionem an subsequatur, quia et posteriorem uoluntatem praetor tueri debet. §39.3.10.2Si flumen nauigabile sit, non oportere praetorem concedere ductionem ex eo fieri Labeo ait, quae flumen minus nauigabile efficiat.
And it is accepted that it makes no difference whether the consent precedes the drawing of water or follows it, because the praetor ought to protect even subsequent consent.\n\nIf a river is navigable, Labeo says that the praetor ought not to permit a drawing of water to be made from it which would render the river less navigable.
idemque est et si per hoc aliud flumen fiat nauigabile.
And the same rule applies if another river should thereby be rendered non-navigable [or less navigable].