Water, Air and Mineral Rights

The Scope of Real Property: Subsurface and Air Rights

Real property ownership is often described as a collection of distinct physical components: the surface of the land, the subsurface below, and the usable airspace above. However, real property ownership does not extend without limit to the center of the earth or outward to infinity. Instead, an owner's interest encompasses the land, subsurface, and usable airspace subject to applicable laws and any rights held by other parties. A fee simple absolute conveyance transfers the rights that the grantor actually owns, which may include surface, subsurface, and air rights, subject to prior severances, deed provisions, and governing law.

Subsurface rights involve underground resources such as minerals, oil, gas, and geothermal elements. An owner who holds subsurface rights may utilize or convey these underground assets. Importantly, subsurface rights can be severed and conveyed separately from the surface estate, resulting in two distinct property interests owned by different parties: a surface estate and a mineral estate. Unless restricted by contract or law, the party holding the mineral rights possesses an implied right of reasonable access to the surface to explore for and extract those minerals. To balance these competing interests, the law provides the surface owner with a right of subjacent support, which protects the surface against subsidence caused by underground mining or drilling, subject to applicable law and any valid agreements. Additionally, all landowners hold a right of lateral support, meaning their land is entitled to physical support on its sides from adjacent land in its natural state.

Mineral extraction is also shaped by common legal and contractual mechanisms. Under the rule of capture, a lawful well operator is generally permitted to keep all oil or gas produced from a well situated on their tract, even if those resources migrated through underground formations from neighboring land, subject to state conservation rules and correlative-rights regulations. Surface owners and mineral holders frequently interact through mineral leases, which grant a lessee the legal right to explore and extract minerals in exchange for royalties and sometimes rent or an initial bonus; the lessor granting this lease does not need to own the surface estate. In some jurisdictions, dormant mineral laws allow unused mineral interests to be extinguished or reunited with the surface owner once statutory conditions and procedures are satisfied. If a party holds a profit à prendre, they possess a nonpossessory interest granting the specific right to enter another person's land to remove natural resources, such as minerals, gravel, or timber.

Air rights encompass the authority to use, control, and develop the usable airspace above a parcel of land. Subject to applicable legal limits, these rights can be leased, sold, or encumbered separately from the land itself. For instance, in dense metropolitan areas, a property owner might sell the airspace above a commercial building to an adjacent developer. Air rights are subject to federal aviation law and the public right of transit through navigable airspace, but unusually low flights that substantially interfere with the use of land may give rise to a property owner's claim. Physical construction into the air may be limited by applicable zoning, building codes, and aviation rules, including height restrictions where they apply. Where authorized by local programs, an owner may participate in a transfer-of-development-rights program to move unused development potential from one parcel to another eligible site, though development rights are not necessarily identical to air rights. Property owners may also establish a solar easement, which is a legally recognized right protecting access to sunlight, with creation and enforcement governed by state and local laws.