Accretion in real estate is the slow, natural buildup of soil, sand, or silt along a shoreline or riverbank, and the new ground belongs to whoever owns the adjacent property. The U.S. Supreme Court has called this right “an inherent and essential attribute of the original property,” rooted in the idea that waterfront owners bear the risk of losing ground to erosion and deserve the upside when nature adds to it instead.1Library of Congress. County of St. Clair v. Lovingston, 90 U.S. 46 (1874) The basic rule is simple. The exceptions, which involve navigable waterways, sudden events, and construction nearby, are where things get complicated.
How the Land Forms
Water currents carry sediment and drop it along banks and shores. Over months and years, these deposits (collectively called alluvion) solidify into usable ground that attaches to the existing shoreline and extends it outward.
For the gain to count as accretion under the law, two conditions have to be met. The process has to be natural: rivers shifting course, tides moving sand, currents dropping silt along a bend, with no one engineering the result. And the change has to be gradual and imperceptible as it happens. You won’t watch the land grow. You’ll notice over time that the shoreline has crept outward. The Supreme Court has defined accretion in exactly these terms, as a slow, natural, and imperceptible addition of land to a bank or shore.2Justia. Nebraska v. Iowa, 143 U.S. 359 (1892)
Who Owns the New Land
Accreted land belongs to the owner of the adjacent upland parcel. The rule applies to riparian owners (property along rivers and streams) and to littoral owners (property along lakes, seas, or oceans). The Supreme Court held in 1967 that a landowner whose property borders navigable water “acquires a right to any natural and gradual accretion formed along the shore,” and that this right traces back to the original grant of the land.3Justia. Hughes v. Washington, 389 U.S. 290 (1967)
The reasoning is a mix of fairness and practicality. Waterfront owners live with the risk that erosion will eat their property, and courts treat the possibility of gaining accreted land as the other side of that bargain. In the Supreme Court’s words, “the owner takes the chances of injury and of benefit arising from the situation of the property. If there be a gradual loss, he must bear it; if a gradual gain, it is his.”1Library of Congress. County of St. Clair v. Lovingston, 90 U.S. 46 (1874) There is also a straightforward problem the rule prevents: if accreted land went to someone else, a strip of third-party ground would eventually separate the original owner from the water and destroy the waterfront access that makes the property valuable.
You don’t pay anyone for accreted land. There is no fee to the government and no buyout from neighbors. The gain comes with the title to the adjacent parcel. One caveat matters: if your deed sets a fixed boundary that does not follow the water, such as a survey marker at specific coordinates rather than a reference to the river’s edge, you may not have an automatic claim to ground that forms beyond that line.
When the Water Is Navigable
Ownership gets more complicated when the adjacent water is legally navigable. Under the Submerged Lands Act, states own the land beneath navigable waters up to the ordinary high water mark on non-tidal rivers and up to the mean high tide line on tidal waters.4Office of the Law Revision Counsel. 43 USC 1301 – Definitions The state holds title to the submerged bed; the private owner holds the upland above the water mark.
When accretion pushes the shoreline out, that boundary moves with it. The upland owner gains the newly dry ground, and the state’s ownership shifts to the submerged area further out. The public trust doctrine then sets the outer limit of what you own. States hold navigable waterways and their beds in trust for the public, and courts have broadly held that these sovereign lands cannot pass into private ownership. Your title runs to the current water’s edge, not beneath it. If the water later returns and resubmerges your accreted ground, the state’s claim to the submerged area reasserts itself.
On non-navigable streams and lakes, the balance tilts toward private owners. The upland owner typically holds title to the center of a non-navigable stream or the bed of a non-navigable lake, so accretion on these waters raises fewer sovereignty questions.
Accretion vs. Avulsion
The line between accretion and avulsion is one of the most consequential in property law, because the two trigger opposite ownership rules.
Avulsion happens when water suddenly and visibly moves a chunk of land. A flood tears away a section of riverbank. A storm reshapes a shoreline overnight. When that occurs, the original property boundaries do not move. The line stays where it was before the event, even if the water itself has shifted somewhere new. The Supreme Court put it plainly: avulsion “works no change of boundary,” and the line remains in the center of the old channel even if no water flows there anymore.2Justia. Nebraska v. Iowa, 143 U.S. 359 (1892)
Accretion is the mirror image. Because the land builds up imperceptibly, the boundary moves with the water’s edge, and the adjacent owner gains (or loses, through erosion) ground automatically. The practical consequence: if a river jumps its banks in a storm and exposes new ground, that is avulsion, and whoever owned the submerged land still owns it. If the same river gradually deposits sediment over a decade, that is accretion, and the adjacent landowner picks up the new ground.
Reliction: Land Gained From Receding Water
Accretion is not the only way waterfront property grows. Reliction occurs when a body of water gradually and permanently recedes, exposing dry land that was previously submerged. A lake that shrinks over decades, or a river channel that imperceptibly shifts away from one bank, leaves behind relicted land.
The ownership rules match accretion. Land exposed through reliction belongs to the adjacent owner, as long as the recession was gradual. Federal law lists reliction alongside accretion as a process that modifies the boundary of lands beneath navigable waters.4Office of the Law Revision Counsel. 43 USC 1301 – Definitions Courts sometimes group the two together under the accretion umbrella.
Artificial Buildup Is a Different Problem
Not all land buildup qualifies. If you dump rocks or soil into a river or bay to extend your lot, you don’t own the result. That is encroachment on sovereign submerged lands, and most jurisdictions deny ownership claims to ground created this way. It is sometimes called the landfill rule.
The gray area is indirect artificial accretion, where land builds up naturally but only because an upstream dam, a neighbor’s jetty, or a government construction project altered the flow. Some courts have applied accretion principles and awarded the land to the upland owner. Others have held that the state or the party who caused the change retains a claim. If your shoreline has grown because of nearby construction rather than purely natural forces, get a legal opinion before relying on the extra acreage.
What You Can Actually Do With Accreted Land
Owning the land does not mean you can build on it freely. Ground that forms at the water’s edge frequently qualifies as wetland, and federal law restricts what you can do with wetlands.
Section 404 of the Clean Water Act requires a permit before anyone discharges dredged or fill material into waters of the United States, wetlands included.5Office of the Law Revision Counsel. 33 USC 1344 – Permits for Dredged or Fill Material If your accreted land contains wetland areas, and much of it will, you need a Section 404 permit from the Army Corps of Engineers before placing fill, grading, or building structures. The requirement reaches activities as ordinary as putting a driveway across a wet area or grading a foundation pad.6U.S. EPA. Permit Program under CWA Section 404 Converting wetlands to a non-wetland use, such as clearing for a house site, specifically requires a permit if it would impair the flow or reduce the reach of the waters. State and local rules often add setbacks, buffer zones, and flood-zone restrictions on top. Check with the Corps of Engineers and your local planning department before you plan anything.
Making the Ownership Stick on Paper
Accreted land is yours by operation of law, but your deed probably doesn’t mention it, the county assessor’s records don’t reflect it, and a title company may hesitate to insure it. A few practical steps prevent problems later.
Get a Current Survey
A professional boundary survey is the starting point. The surveyor locates the current ordinary high water mark or mean high tide line, compares it against historical survey data, and calculates the acreage gained. That documentation feeds everything else, including tax assessments, title insurance, permit applications, and any future sale. Waterfront surveys cost more than standard boundary work because establishing a shifting water boundary requires reviewing historical records.
Quiet Title If Anyone Disputes
If a neighbor, a government entity, or a cautious title company challenges your claim, a quiet title action resolves the question. The lawsuit asks a court to determine ownership of real property when competing claims exist. If you prevail, the court issues a judgment confirming your title, and no further challenges can be brought on the same grounds. You carry the burden of proving the land formed through gradual, natural accretion rather than avulsion or artificial fill.
Record the New Description
Even without a dispute, recording an updated survey or new legal description with the county recorder creates a public record of your expanded boundaries. This matters most at sale or refinance, because a buyer’s title company searches public records and an updated filing makes the accreted area part of the insurable title. Without it, a title company may exclude the accreted portion from coverage, which can complicate or kill a sale.
What Happens to Your Property Taxes
More land usually means a higher tax bill. County assessors periodically review parcel data, and an updated survey showing additional acreage can trigger a reassessment. The accreted ground is valued based on what it is: buildable waterfront commands more than marshy wetland that can’t be developed. Wetland or flood-zone restrictions may limit the tax impact, but the added square footage alone can still push the assessment up.
Timing varies. Some owners go years before the assessor catches up, especially if no survey has been recorded. Others see an adjustment after a refinance or sale triggers a new appraisal. Either way, the tax obligation follows ownership. If the land is yours, it belongs on your tax rolls whether or not you have formalized the boundary change.