Definition
A civil law servitude granting one party the right to convey water across or through the land of another by means of pipes, channels, or conduits. The right attaches to the dominant estate and burdens the servient estate, obligating the servient landowner to permit the physical infrastructure of water conveyance — not merely the passage of water, but the maintenance of the conduits or pipes necessary to move it.
The term is Latin: aquae ductus translates literally as "leading of water" or "drawing of water." It appears in the Digest and the Institutes as one of the recognized praedial servitudes governing use of another's land for water-related purposes in Roman law.
Note on spelling: The term is correctly rendered AQUAE DUCTUS. The form "AQUZ DUCTUS" does not appear in legal sources and represents a typographical corruption of the Latin. Researchers encountering this form in indexes or digitized sources should treat it as a scanning or transcription error for AQUAE DUCTUS.
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Common Confusion
AQUAE DUCTUS is one of several related Roman water servitudes that researchers frequently conflate. AQUAE HAUSTUS is the right to draw water from another's land — the right to access and collect water at its source. ITER AD AQUAM (or ACTUS AD AQUAM) is the right to cross another's land to reach water. AQUAE DUCTUS is distinct in that it concerns active conveyance of water through infrastructure across the servient estate, not mere access or drawing rights. A researcher finding a reference to a "water servitude" in a civil law jurisdiction must identify which specific right is at issue, as the obligations imposed on the servient estate differ meaningfully among them.
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Why It Matters in Research
AQUAE DUCTUS is a term encountered primarily in three research contexts: (1) civil law property scholarship and treatises dealing with servitudes; (2) historical water rights litigation in jurisdictions with a civil law heritage, particularly Louisiana, and to some extent the water law traditions of the American West and Latin American jurisdictions; and (3) comparative law analysis contrasting Roman-derived servitude frameworks with common law easement doctrine.
Researchers working in common law sources should understand that AQUAE DUCTUS has no direct common law counterpart as a named category. English and American common law absorbed the functional equivalent under the general heading of easements — specifically easements for watercourses or pipeline easements — without retaining the Roman terminology. A researcher who encounters AQUAE DUCTUS in a 19th-century American treatise is almost certainly reading a civil law comparison or a Louisiana-specific source, not a term of art operative in common law courts.
In Louisiana, where the Civil Code preserves a civilian servitude framework, the functional concept survives in codified form even if the Latin label is not always used. Researchers working in Louisiana property law should cross-reference the Civil Code's servitude provisions alongside Roman sources.
The Digest citation (Dig. 8, 3, 1) and Institutes citation (Inst. 2, 3) in Black's are references to Justinian's Corpus Juris Civilis — real and verifiable primary sources. Researchers with access to translated editions of the Digest (such as the Mommsen-Krueger edition or the Watson translation) and the Institutes can consult these directly. Dig. 8, 3 is the title "De servitutibus praediorum rusticorum" (On the servitudes of rural estates), where aquae ductus is treated alongside other rural praedial servitudes.
One indexing trap: digitized versions of older legal dictionaries frequently corrupt Latin entries through optical character recognition errors. AQUAE DUCTUS may appear as "AQUZ DUCTUS," "AQUAE DUCTUZ," or similar in searchable databases. If a search on the corrupted form yields no results in a legal database, search instead on AQUAE DUCTUS or the component terms aquae and ductus.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) provides a concise and accurate entry, correctly identifying AQUAE DUCTUS as a civil law servitude for conveying water via pipes or conduits across another's estate and citing the relevant Digest and Institutes passages. The definition is faithful to the Roman source material.
What Black's does not provide — and what researchers should seek elsewhere — is any treatment of how this servitude operated in practice under Roman law: the rules governing the width of the right of way, the obligation to maintain conduits, or the relationship between aquae ductus and the other water servitudes. For that depth, civilian treatises and the annotated Digest are necessary. Domat's Civil Law and Pothier's works, available in 19th-century English translations, discuss the civil law servitude framework and provide more context than any entry-level legal dictionary.
No meaningful divergence exists among historical legal dictionaries on this term — it is a narrowly defined Roman law category that passed into modern legal reference sources essentially unchanged. The primary scholarly interest lies not in definitional dispute but in understanding its application in surviving civil law jurisdictions.
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Jurisdictional Note
AQUAE DUCTUS as a named legal category is operative primarily in civil law jurisdictions. Louisiana is the principal U.S. jurisdiction where the underlying concept retains direct doctrinal relevance. In common law jurisdictions, the functional equivalent is addressed through easement law without reference to the Roman term.
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