Definition
Latin for "water." In civil law and old English law, *aqua* denotes water in its legal sense — as a subject of property rights, easements, and use entitlements. The term appears most often not in isolation but as the root of compound Latin phrases, each describing a legally significant category of water or water right.
Principal compound forms as used in the sources:
1. *Aqua currens* — Running water; water in motion through a defined channel.
2. *Aqua dulcis* (also *aqua frisca*) — Fresh water, as distinguished from tidal or salt water.
3. *Aqua fontanea* — Spring water; water arising from a natural spring.
4. *Aqua profluens* — Flowing or running water; used in Roman law to describe water in continuous natural motion.
5. *Aqua pluvia* — Rain water; water falling from the sky (*quae de caelo cadit*).
6. *Aqua quotidiana* — Daily water; water available for drawing at any time of year, without seasonal restriction.
7. *Aqua aestiva* — Summer water; water whose use was limited to the summer season under Roman law.
The maxim *aqua cedit solo* — water passes with the land — reflects the foundational civil law principle that a grant of land ordinarily carries with it the water rights appurtenant to it.
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Common Language
Modern common usage (Wiktionary): *Aqua* in everyday English refers to a color — a blue-green shade resembling turquoise — or, in scientific and pharmaceutical contexts, water as a compound (H₂O).
Historical common usage (Webster's 1913): Webster's treats *aqua* primarily as a pharmaceutical and chemical term: water used as a solvent or medium, as in *aqua regia* (the nitric/hydrochloric acid mixture) and *aqua ammoniæ*. The color meaning is not yet dominant.
The gap between common and legal meaning is total. In legal research contexts, *aqua* carries no color meaning and no pharmaceutical meaning. It is strictly a term of property and civil law, concerned with classification of water types and the allocation of rights in water — a category of analysis that has no overlap with the color swatch or chemistry bench.
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Recognized Forms
/SUBTYPES
The term functions primarily as a Latin root generating compound terms. The principal subtypes recognized in the historical dictionaries are those listed in the definition above: *aqua aestiva*, *aqua currens*, *aqua dulcis/frisca*, *aqua fontanea*, *aqua profluens*, *aqua pluvia*, and *aqua quotidiana*. Each has distinct legal significance relating to the nature, seasonality, source, or quality of water at issue in a given dispute or grant.
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Why It Matters in Research
**Compound terms are the real research targets.** Researchers encountering *aqua* alone in a legal source are almost certainly looking at a fragment — the meaningful content lies in the full compound phrase. Indexing and headword searches for *aqua* in isolation will surface the root but not the doctrine. Always search for the specific compound form relevant to the water-right question at hand.
**Roman law transmission.** Most *aqua* compounds derive directly from Justinian's Digest and Code. Sources citing Dig. 39.3 (on rain water and drainage), Dig. 43.20 (on water use and aqueducts), and Cod. 3.34 (on water disputes) are engaging Roman law directly. English and American courts occasionally cited these passages through the early common law treatise tradition — particularly through Bracton and Fleta — when resolving questions of riparian right, drainage obligation, and water servitude.
**The *aqua cedit solo* maxim.** Anderson's entry flags this as a live principle affecting grants and deeds: a conveyance of land carries water rights unless expressly reserved. Researchers working in property law, land grants, or water rights disputes should treat this maxim as a doctrinal anchor that bridges civil law sources and early American case law. Anderson cites *United States v. Ford* (the *Whiskey Cases*), 99 U.S. 599 (1878), and *Oliver v. Commonwealth*, 77 Va. 592 (1883), as examples of contexts where appurtenant rights language was litigated.
**Fresh vs. tidal water distinctions.** The *aqua dulcis/frisca* category had direct practical significance in early English and American law: different common law rules governed fresh water and tidal (salt) water, particularly regarding the public right of fishery, navigation, and the location of property boundaries. Sources using *aqua dulcis* or *aqua frisca* are signaling which regime applies.
**Seasonal water rights.** *Aqua aestiva* and *aqua quotidiana* reflect Roman servitude law distinctions that occasionally appeared in American irrigation and water-right disputes in arid Western states, where seasonal availability of water was economically critical. Researchers in Western water law should note that these Roman categories sometimes informed the conceptual vocabulary of early territorial and state court decisions.
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Historical Dictionary Support
The four source dictionaries converge on the basic definition — Latin for water, sometimes a watercourse — but differ in depth and utility.
Burrill's is the most comprehensive, citing Digest and Code passages directly and enumerating the compound forms with their source references. It is the most useful of the four for tracing a specific *aqua* compound back to its Roman law origin.
Black's (2nd ed.) organizes the compounds as subordinate headwords under the main entry, making it useful for quick identification of a term encountered in a text, though its Digest citations contain minor transcription irregularities common to the period.
Anderson's is the most practically oriented, focusing on the *aqua cedit solo* maxim and its application in American courts. It provides the only case law references in the set and is therefore the most useful for researchers working in American common law rather than civil law sources.
Black's (1st ed.) offers the minimal definition — water; sometimes a stream — without enumeration of compounds, making it least useful for this term specifically.
None of the four sources addresses modern water law statutory frameworks, which have largely superseded these common law and civil law categories in American jurisdictions.
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Jurisdictional Note
Civil law *aqua* terminology remains most relevant in Louisiana, where the civilian tradition directly informs water law doctrine. In common law states, the compound terms appear primarily in historical sources and early cases drawing on the treatise tradition. Western states with prior appropriation water law systems developed largely independently of these Roman categories, though traces of the civil law vocabulary appear in 19th-century territorial court opinions.
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