Accession is the right of an owner to everything that is produced by their property, or that is incorporated or attached to it, naturally or artificially. Along rivers, alluvion, the soil gradually and imperceptibly deposited by the current, belongs to the owner of the adjoining riverbank land. In avulsion, where a known portion of land is suddenly detached and carried to another's land by the force of a river, it still belongs to the original owner, who may remove it within the period the law allows. Accession also governs who owns what is built, planted, or sown on another's land.
Land is not always static. Rivers add soil, floods move earth, and people build on ground that turns out to be someone else’s. The Civil Code’s rules on accession decide who owns what nature or human effort adds to property.
What Accession Is
Accession is the right of the owner of a thing to everything it produces, or which is incorporated or attached to it, whether naturally or artificially. It flows from ownership: what your property generates or gains, you generally own. Accession comes in two broad forms — accession discreta (the fruits your property produces) and accession continua (what is joined or added to your property, by nature or by people).
Alluvion: Soil the River Gives
The classic natural accession is alluvion. To the owners of lands adjoining the banks of rivers belongs the accretion which they gradually receive from the effects of the current of the waters. This soil, deposited gradually and imperceptibly, becomes part of the riverbank owner’s land by operation of law. Two conditions matter: the deposit must be gradual and imperceptible, and it must be caused by the current of a river (not, say, by a lake or artificial means). Note that alluvion, though owned by the riparian owner, is not automatically registered — the owner may need to title it, and until then it can be subject to acquisition by others through prescription in limited situations.
Avulsion: Land the River Takes and Moves
Avulsion is the sudden counterpart. Whenever the current of a river segregates a known portion of land from one estate and transfers it to another (suddenly, not gradually), the land still belongs to the original owner. Unlike alluvion, the transferred portion does not become the other owner’s; the original owner may reclaim or remove it, but must do so within the period the law provides, or lose the right. The difference from alluvion is suddenness and identifiability: alluvion is imperceptible deposit (new owner); avulsion is a sudden, known chunk (original owner keeps it).
Building, Planting, and Sowing
Accession also resolves the frequent problem of building, planting, or sowing on land, especially another’s land:
- Whatever is built, planted, or sown on a parcel is generally presumed made by the owner and at their expense, unless the contrary is proven;
- Where a person builds, plants, or sows in good faith on another’s land, the landowner has options — to appropriate the improvement upon paying indemnity, or to require the builder to buy the land (or pay rent), under the good-faith rules; and
- A bad-faith builder loses what they built without indemnity, and may be liable for damages, while a landowner in bad faith has correspondingly reduced rights.
These rules connect to the doctrine of the builder in good faith, discussed in a separate commentary.
Practical Advice
- Riverbank owners: gradual accretion (alluvion) belongs to you — but title it, since it is not automatically registered.
- If a sudden flood moved a known part of your land to a neighbor (avulsion), you keep it — but act within the period to reclaim or remove it.
- If someone built on your land, or you built on another’s, the good-faith rules govern who pays whom — get advice before demolishing or paying.
Frequently Asked Questions
Who owns soil gradually deposited by a river on my land? You do. Alluvion, the accretion gradually and imperceptibly deposited by the current of a river on adjoining bank land, belongs to the riparian owner by operation of law, though it may need to be titled.
What if a flood suddenly moved a piece of my land to a neighbor? That is avulsion. The known portion still belongs to you, the original owner, and you may reclaim or remove it, but within the period the law provides, or you lose the right.
Who owns what is built on a piece of land? Whatever is built, planted, or sown is presumed made by the owner at their expense unless proven otherwise. If someone builds in good faith on another's land, the good-faith rules govern who pays whom.
What is the difference between alluvion and avulsion? Alluvion is imperceptible, gradual deposit that becomes the riparian owner's land. Avulsion is a sudden transfer of a known, identifiable portion, which remains the original owner's property.
This commentary is for general informational purposes only and does not constitute legal advice. For guidance specific to your situation, please consult a licensed attorney.
If a river changed your land or someone built on it, our firm can advise you on ownership under the rules of accession. You may reach us via Viber or WhatsApp, call us at 0995 433 5550, or send an email to vivasnobles@gmail.com. We look forward to hearing from you.