21.2 Environmental Law, Water Rights, Oil & Gas

Key Takeaways

  • NALS lists environmental, water, and oil and gas as three separate areas of law under Part 4 Legal Knowledge.
  • CERCLA imposes strict, joint and several, and retroactive liability on four categories of potentially responsible parties, and the innocent landowner and bona fide prospective purchaser defenses require all appropriate inquiries such as a Phase I environmental site assessment.
  • NEPA is procedural: it compels federal agencies to study and disclose environmental effects of major federal actions, not to choose the least damaging alternative.
  • Eastern states generally follow riparian rights tied to land bordering a watercourse, while western states generally follow prior appropriation under which the first to put water to beneficial use has the senior right.
  • The mineral estate is dominant over the surface estate once severed, giving the mineral owner an implied right of reasonable surface use to extract the minerals.
Last updated: September 2026

21.2 Environmental Law, Water Rights, Oil & Gas

[!NOTE] NALS PP Exam Blueprint Focus: Environmental, water, and oil and gas each appear as separate entries among the twenty-five areas of law NALS lists under Part 4 Legal Knowledge. They are grouped here because they all allocate rights in natural resources and because a single real estate or energy transaction routinely touches all three.


Part One: Environmental Law

The Major Federal Statutes

StatuteWhat it does
National Environmental Policy Act (NEPA)Requires federal agencies to assess the environmental effects of major federal actions significantly affecting the human environment
Clean Air ActNational ambient air quality standards, state implementation plans, permitting for new and modified sources
Clean Water ActProhibits discharge of pollutants from a point source to waters of the United States without an NPDES permit; Section 404 governs dredge and fill in wetlands
Safe Drinking Water ActStandards for public water systems; underground injection control
Resource Conservation and Recovery Act (RCRA)Cradle-to-grave regulation of hazardous waste generation, transport, treatment, storage, and disposal, tracked by manifest
CERCLA (Superfund)Liability and cleanup for releases of hazardous substances at contaminated sites
Toxic Substances Control ActChemical inventory, testing, and restrictions
Endangered Species ActProhibits taking of listed species; consultation and incidental take permitting
FIFRAPesticide registration and labeling
Emergency Planning and Community Right-to-Know ActReporting of chemical inventories and toxic releases

[!TIP] NEPA is procedural, not substantive. It forces an agency to study and disclose environmental consequences and to consider alternatives. It does not require the agency to pick the environmentally preferable option. An agency that fully documents the harm and proceeds anyway has complied with NEPA. The process runs categorical exclusion, then environmental assessment leading either to a finding of no significant impact or to a full environmental impact statement.

CERCLA Liability

CERCLA liability is strict, joint and several, and retroactive — it reaches conduct that was entirely lawful when it occurred.

The four categories of potentially responsible parties

PRP categoryWho it captures
Current owner or operatorWhoever owns or operates the facility now, even if they contributed nothing to the contamination
Owner or operator at the time of disposalHistoric owners and operators during the disposal period
Arrangers (generators)Those who arranged for disposal or treatment of hazardous substances
TransportersThose who transported and selected the disposal site

The first category is what makes environmental due diligence indispensable in real estate practice: a purchaser who never spilled anything can become fully liable for a predecessor's contamination simply by taking title.

Defenses

The statutory defenses are narrow: an act of God, an act of war, and the third-party defense. Two derivative protections built on the third-party defense do the real work in transactions:

ProtectionRequirement
Innocent landownerAcquired the property without knowledge of contamination after conducting all appropriate inquiries before acquisition
Bona fide prospective purchaserAcquired with knowledge of contamination but performed all appropriate inquiries, disposed of nothing, and complies with continuing obligations including care and cooperation
Contiguous property ownerAdjacent owner contaminated by migration from a neighboring site, with comparable diligence and cooperation requirements

All appropriate inquiries is satisfied by a compliant Phase I environmental site assessment: records review, site reconnaissance, interviews, and a report identifying recognized environmental conditions. A Phase I involves no sampling; if it identifies recognized environmental conditions, a Phase II with sampling and laboratory analysis follows. A Phase I has a limited shelf life and must be updated to remain current for the protections.

Cleanup and cost recovery

EPA may perform the cleanup and recover costs, or compel PRPs to perform it. PRPs may sue each other for contribution to allocate costs by equitable factors, and settling parties obtain contribution protection. Brownfields programs and state voluntary cleanup programs offer liability relief in exchange for supervised remediation, and institutional controls such as deed restrictions and environmental covenants often accompany a completed cleanup.


Part Two: Water Rights

Surface Water: Two Systems

Riparian rightsPrior appropriation
WhereGenerally the eastern United States, where water is plentifulGenerally the western United States, where water is scarce
Who holds the rightOwners of land bordering the watercourseWhoever first put water to beneficial use, regardless of land location
Basis of priorityAll riparians share; use must be reasonable relative to other ripariansFirst in time, first in right — seniority governs
Effect of non-useRight generally persistsRight may be forfeited or abandoned for non-use
In shortageRiparians share the reductionSenior rights are satisfied in full before junior rights receive anything
TransferabilityTied to the riparian landOften transferable separately from land

Some states apply a hybrid system recognizing riparian rights established before a statutory date and appropriative rights thereafter.

The prior appropriation elements are intent to appropriate, diversion, and application to a beneficial use, with the priority date fixed at initiation. Modern statutes administer the system through permits and adjudicated decrees, and a call by a senior right holder in a dry year shuts off junior diverters entirely.

Federal reserved water rights attach to federal reservations such as tribal lands and national parks, with a priority date as of the reservation and no requirement of actual diversion.

Groundwater Doctrines

DoctrineRule
Absolute dominion (English rule)An overlying owner may pump without liability, subject to limited exceptions
Reasonable use (American rule)Pumping must be for a reasonable use, ordinarily on the overlying land
Correlative rightsOverlying owners share a common supply proportionally in times of shortage
Prior appropriationGroundwater is allocated by seniority like surface water

Many states now manage groundwater through permits, designated management areas, and pumping limits, and increasingly recognize the hydrologic connection between groundwater and surface flows.

Related Concepts

  • Diffused surface water — runoff not in a defined channel; states apply the common enemy rule, the civil law rule, or a reasonable use rule to drainage disputes.
  • Navigability determines public rights of use and the boundary of state title to submerged lands.
  • Accretion, reliction, avulsion, and erosion govern how boundaries move when a watercourse shifts.

Part Three: Oil & Gas

Severance and the Dominant Mineral Estate

Land ownership can be split into a surface estate and a mineral estate. Once severed, the two can be conveyed, taxed, and encumbered independently.

[!WARNING] The mineral estate is dominant. The mineral owner holds an implied right to make reasonable use of the surface as necessary to explore for and produce the minerals — access roads, well pads, pipelines — even over the surface owner's objection. Surface owners protect themselves through negotiated surface use agreements and, in some states, statutory accommodation doctrines requiring the operator to accommodate existing surface uses where reasonable alternatives exist.

The mineral estate comprises a bundle of rights: the right to develop, the right to lease (the executive right), the right to receive bonus payments, the right to receive delay rentals, and the right to receive royalty. Each can be conveyed separately, which is why title work in producing areas is intricate. A royalty interest is a non-cost-bearing share of production; a working interest bears the costs of drilling and operating.

The Rule of Capture and Correlative Rights

Under the rule of capture, an owner acquires title to the oil and gas produced from wells on that owner's land even if the hydrocarbons migrated from beneath a neighbor's tract. The rule drove wasteful competitive drilling, so states responded with correlative rights and conservation regulation: well spacing rules, allowable production limits, and prohibitions on waste, administered by a state conservation commission or oil and gas board.

The Oil and Gas Lease

An oil and gas lease is, in most producing states, a conveyance of an interest in real property rather than a simple lease.

ClauseFunction
Granting clauseConveys the right to explore, drill, and produce, and describes the leased premises
Habendum clauseSets the primary term, a fixed number of years, continuing into a secondary term for so long as oil or gas is produced in paying quantities
Royalty clauseThe lessor's cost-free share of production, historically one-eighth and frequently higher in modern leases
BonusA lump sum paid at signing
Delay rentalPayment to defer the obligation to drill during the primary term
Pooling clauseAuthorizes the lessee to combine the tract with others into a drilling unit
Shut-in royaltyMaintains the lease when a well capable of production is shut in for lack of a market
Force majeureExtends obligations during specified events beyond the lessee's control
Pugh clauseSevers undeveloped acreage or deeper formations from the held acreage at the end of the primary term

Courts also imply covenants into oil and gas leases, including duties to develop reasonably, to protect against drainage, and to market production.

Pooling and Unitization

Pooling combines small tracts into a single drilling unit satisfying spacing requirements, either voluntarily under a lease pooling clause or by compulsory or forced pooling ordered by the state regulator when an owner refuses to join. Unitization combines a whole field or reservoir for coordinated operation, typically for secondary recovery. Production anywhere in the unit is allocated to all tract owners by their proportionate share, which means production from a neighbor's tract can hold an owner's lease and generate royalty.

The Paralegal Workstream

TaskContent
Title runsheets and chainsTrace surface and mineral conveyances separately through the county records
Division ordersConfirm decimal interests before revenue is distributed
Lease abstractingExtract terms, expiration dates, and obligations into a lease database
Regulatory filingsPermits to drill, completion reports, spacing and pooling applications
Curative workAffidavits of heirship, corrective deeds, releases of expired leases
Environmental diligenceCoordinate Phase I assessments and regulatory database reviews on acquisitions
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CERCLA Liability and the Diligence That Defeats It
Test Your Knowledge

A company buys a former dry-cleaning site, performing no environmental investigation before closing. Groundwater contamination from solvents used by a prior owner in the 1970s is discovered two years later. What is the buyer's CERCLA exposure?

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Test Your Knowledge

In a western prior appropriation state, Rancher A has an 1889 water right and Farmer B has a 1974 right on the same stream. In a drought year the flow is sufficient to satisfy only about half the decreed rights. How is the water allocated?

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Test Your Knowledge

A landowner sells the surface of a 400-acre tract but reserves the entire mineral estate. The mineral owner later leases to an operator, who plans access roads and a well pad across pastureland the surface owner uses for grazing. What is the surface owner's position?

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