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  • Robert T. Caccese, Esq., Staff Attorney

An Overview of Pennsylvania Water Law

Updated: Dec 16, 2022


Pennsylvania (PA) is a unique state with regard to water management and law. The state boasts over 86,000 miles of streams, borders Lake Erie, contains an abundance of surface lakes and ponds, and possesses a variety of groundwater aquifer types. Furthermore, Pennsylvania is home to a national forest, over two million acres of state forest land, and over one and a half million acres of public hunting grounds (state game lands), each containing important water resources. The state is comprised of six major watersheds, contains a variety of water users (commercial and private), and is susceptible to extreme precipitation events (floods and droughts) in light of a perceived stable, wet climate. Like states east of the 100th Meridian, Pennsylvania water law adheres to riparian doctrine, but distinguishes itself from other states through a lack of a statewide water permitting regime and presence of two interstate river basin commissions regulating 2/3 of the state. Likewise, a number of statutes regulate certain aspects of water management, such as pollution, energy exploration, and dam operations. Moreover, predictions of population increases, demands from natural gas exploration, a large presence of reservoirs, Chesapeake Bay water quality improvement mandates, and preserving aquatic species all pose additional considerations toward sustainably managing the state’s water resources into the future. Water quality and state water planning is the responsibility of the state Department of Environmental Protection. According to the 2010 USGS Water Use Report, Pennsylvania withdrew an average 8,130 million gallons of water per day. Of the total, public water supply accounted for 1,420 and thermoelectric power withdrew close to 5,390 million gallons per day. Aquaculture accounted for the third highest use averaging about 866 million gallons per day.

As a brief water law primer, the United States uses two legal systems for water regulation: prior appropriation doctrine in the western U.S. and riparian law in the east. Prior appropriation involves the actual diversion of water from a source to be put to use by an individual. The water system is beneficial in a number of ways. First and foremost, water uses must be put to “beneficial use”, a term that has been loosely defined by courts. Recognized beneficial uses include mining, irrigation, domestic (household uses), municipal (drinking water supply), and more recently, instream flow rights for fish or recreation purposes. Prior appropriation has positive attributes in the “first in line, first in right” theory of senior rights, the enforceability of water uses as property rights, and marketability reasons, such as trusts and exchanges (rights can be sold/bought). In addition, rights holders have certainty over the amount of water they may use and the place of use for the water. This is usually found in a paper right, similar to someone having a deed to a house. Tied to this right is a priority date, so those individuals with the earliest known dates (“senior holders”) secured to their water right have the most seniority to use water, even in times of drought.

By contrast, riparian doctrine is predominately used in the eastern U.S. and is based off the idea of a land owner abutting a water body to have a right to continued flow of water in the same quality and quantity. Water rights under riparian law are limited to “riparians”, meaning landowners abutting a water way. Riparian rights cannot be sold or severed, and are “attached” to the land. The right to a certain quality of water is recognized by courts in Pennsylvania. Riparians may exercise water rights at any time and new users who obtain a right are on equal footing with existing owners.

For this paper, research for PA water law comprised the following, but not limited to, sources:

- 4-PA Waters and Water Rights I-VIII (2017); 4-DE-RB Water and Water Rights I-VII (2017) - A Short Review of Pennsylvania Water Law, Pam Bishop, Asst. Counsel, PA DEP (2006) - A Quick Guide to Groundwater in Pennsylvania, Penn State Extension - Development of the Marcellus Shale-Water Resource Challenges, R. T. Weston, K&L Gates - 27 Pa.C.S.A. §3111-3120 (2003) (PA State Water Plan)

* For readability purposes, citations are not provided in the text.

* Disclaimer: This document is not legal advice nor a substitute for the legal advice of an attorney. In the event of a potential cause of action, please consult a lawyer for further guidance.*

Common Law Riparianism

Pennsylvania water law can be best described as various pieces of law interwoven together to manage water, but is not well designed for future demands and emergency situations. In addition, allocation of water is not quantified nor do sufficient databases exist to amend regulatory development based on the best science available. Sources of PA water law include common law, interstate compacts regulating some parts of the Commonwealth, and statutes targeting specific water topics. Both surface and groundwater are legally managed separately under riparian law, but the recent state water plan has recommended managing both conjunctively as science of hydrological connectivity continues to be advanced. Under the common law, PA water is classified in four ways: surface water, diffused surface water, groundwater in well-defined subterranean streams, and percolating groundwater.

Surface Water

Under common law origins with respect to riparianism, Pennsylvania defines surface water as “water in defined streams and lakes.” Separately, “diffused surface water” is mentioned as a classification of water for purposes of riparianism, but cases have not detailed any specific policy or regulatory framework for managing this classification, other than downstream users must accept the natural flow of drainage from upstream owners. Diffused surface water is best understood as runoff water over land as a result of extreme rain events. Riparian rights, with respect to surface water, attach to riparian land: land abutted by a defined waterbody. Another important note is a distinction between natural and artificial waterbodies. Rights attach automatically to a natural waterbody (underground streams and artesian basins included), but rights only attach to artificial waterbodies if they replace natural ones or if landowners adjoining an artificial reservoir agree to treat such a waterbody as if they are riparians. Likewise, questions of the “navigability” of a waterbody defines the scope of potential riparian rights for an abutting landowner such as wharfing out or leasing for mineral exploration. In Pennsylvania, ownership of the bed of a stream or lake affects whether the entire waterbody can be used or not. Non-navigable lakes only allow abutting landowners to use the water column above their portion of the lakebed, rather than the entire waterbody for navigable lakes. According to PA case law, a waterbody is “navigable” if it is susceptible of being used for commercial navigation. Furthermore, the PA Supreme Court has held that if a river is navigable to an extent, it is deemed navigable throughout its entire length. However, questions to how far a waterbody’s length applies under this reasoning and whether it is physically navigable remain questions state agencies disagree on. Moreover, acquisition of riparian land for eminent domain purposes by public service agencies or municipalities requires a permit from the state DEP.

Concerning water use, riparian rights are considered “usufructuary” in nature, meaning the right to use the water, not ownership of the water. Rights are not severable from the land to which they attach, but can be conveyed in the form of an easement to other parties. Questions remain as to the extent of a right conveyed. Furthermore, these types of rights do not expire, unlike water rights adhering to prior appropriation doctrine. In general, water must be put to use related to the overlying/abutting land it is taken from. For surface water use, Pennsylvania adheres to the doctrine of reasonable use, meaning “riparian owners are entitled to the natural flow of the water of a stream, undiminished in quantity and unimpaired in quality, subject to the reasonable use of the water by those similarly entitled, for the ordinary purposes of life.” See Clark v. Pennsylvania Railroad Co. Simply put, users share a waterway equally with others and cannot unreasonable interfere with other riparian rights. Domestic use (i.e. drinking, bathing, livestock, laundry) receives the highest priority of all uses and trumps all uses when a conflict among users occurs. Domestic uses of water may materially diminish the quantity and flow of a stream without penalty. All other uses such as irrigation, industrial, and municipal, are considered “extraordinary uses”, subject to a balancing test and case specific analysis when conflicts among users occur. Litigation remains the primary means to resolve issues among competing water users and navigability must be maintained on watercourses deemed navigable, trumping all uses except domestic purposes. Lastly, Pennsylvania courts do not allow any diversion of water resources from a riparian tract for use outside the tract.


Under common law riparian principles, percolating groundwater adheres to a standard of “reasonable use” that differs slightly from the rule for surface water withdrawals. A landowner may withdraw all groundwater beneath their land for beneficial uses that are lawful. Only malicious or negligent use causing foreseeable harm to a neighboring user warrants an actionable offense. Through this standard, a user may deplete the supply of neighboring lands, as long as the use is lawful and reasonable. Use is unquantified for most users and use for off-tract purposes is not allowed. Often, the user with the deepest well and biggest pump succeeds. Although Pennsylvania is one of two states without well-drilling standards (the other being Alaska), licenses are required for all well drillers. With respect to underground subterranean streams, case-law has not addressed this type of waterbody, as they are naturally rare.

Interstate River Basin Commissions

Pennsylvania is one of a few riparian states without a statewide water permitting agency. In its place, two River Basin Commissions regulate water withdrawals through permits to an extent, but not as detailed as other states’ permitting regimes. The Commissions are meant to be water-planning agencies, but serve as permitting agencies in PA because of the lack of a statewide water permit system. Pennsylvania is a signatory to the Delaware River Basin Compact and Susquehanna River Basin Compact, both creating the Delaware River Basin Commission and Susquehanna River Basin Commission. In addition to PA, NJ, DE, NY, and the federal government are parties to the Delaware Compact; while NY, MD, PA, and the federal government comprise the Susquehanna Compact. Together, both Commissions regulate about 2/3 of PA, while pure common law riparian principles still control the western third of PA.

Delaware River Basin Commission (DRBC)

Adopted in 1961, the Compact created the DRBC and delegated broad powers to the agency including planning, developing, conserving, regulating, allocating, and managing water resources within the Basin. About 15 million people rely on the basin for drinking water. The agency is authorized to approve all projects having a substantial effect on water within the Basin and assures approved projects comply with the comprehensive plan developed by the Commission for water management. The definition of “project” is broad and includes a wide range of activities. Of note, Congress has consented subordination for new federal projects in the Basin to the planning authority of the Commission. With regard to water withdrawals that require a permit, the DRBC must first designate an area as “protected.” A “protected area” is “an area where the demands upon the supply of water have developed or will develop to such a degree to create water shortages or conflict with the requirements of the comprehensive plan for the Basin.” Similarly, the DRBC has the power to declare a water supply emergency when it is determined that an immediate and actual shortage of available water exists. If the agency determines an area is protected or in an emergency, all water projects will require a permit. Projects resulting in surface or groundwater withdrawals of 100,000 gallons per day over a 30-day period average must submit a project proposal to the DRBC before commencing. If the project is approved (does not impair or conflict with comprehensive Basin plan or significantly affect flow), the applicant will receive a permit to withdraw water. Other projects warranting prior approval from the agency include impoundment of water, diversions of 100,000 gpd (gallons per day) into or outside the Basin, and construction/alteration of wastewater treatment plants involving at least 50,000 gpd. The exception to the 100,000 gpd rule is withdrawals located within the Southeastern Pennsylvania Groundwater Protected Area, where new or expanded well water projects involving an average withdrawal of more than 10,000 gpd during a 30-day period from a well or group of wells (system) are required to obtain a permit. Wells must be registered with the agency and permits may have additional conditions attached such as, withdrawal limits, pump testing, and hydrologic analysis prior to pumping groundwater.

With respect to natural gas development, the DRBC instituted a moratorium in 2010 banning such activities, including fracking, within the Basin boundaries. In present day, the moratorium remains in effect, with the agency moving towards a potential permanent injunction from such activities in the Basin.

Susquehanna River Basin Commission (SRBC)

Modeled after the Delaware River Basin Compact, the Susquehanna River Basin Compact was adopted in 1970 and created the SRBC. The powers of the agency are almost identical to those of the DRBC. SRBC requires project approval for all surface and groundwater withdrawals of at least a 100,000 gpd average in a 30 day period, and new or increased consumptive water use in excess of 20,000 gpd. Any project deemed to have a significant adverse impact upon the Basin’s water resources warrants prior approval. “Consumptive use” is defined broadly by the agency as meaning “loss of water transferred through a man-made conveyance system or any integral part thereof due to transpiration by vegetation, incorporation into products during their manufacture, evaporation, injection of water into subsurface storage formation, diversions from the basin, or any other process where water is not returned to the Basin undiminished in quantity.” Under rules from the agency, during periods of low flow, consumptive users must curtail their use or provide compensation for their use. Furthermore, all Marcellus Shale related activities (allowed in this Basin), regardless of water quantity used, are subject to Commission approval prior to any water withdrawals.

In 2002, the SRBC adopted guidance concerning “passby flows” (for aquatic species) and conservation releases of both surface and groundwater projects in the Basin. Passby flows mandate that while water is being withdrawn by a user, a specified amount must pass a certain point downstream of the user from the point of withdrawal. Particular passby flows are determined through an Instream Flow Studies publication by SRBC dating back to 1998. By contrast, conservation releases only involve surface projects and can be mandated during times of normal flow. Furthermore, the agency released a report in 2016 regarding cumulative water use and availability across the Basin in present day and into the future.

In general, the Basin Commissions are limited by their geographic jurisdiction and require permits for the biggest water users within each Basin. Although some regulation is better than Pennsylvania common law, the regulatory authority of the agencies is still limited compared to statewide permitting regimes in other eastern states.

Statutory Authority

Aside from the allocation policies of the two interstate basin commissions, a few important state statutes regulate pollution, dam operations, public water suppliers, and water planning within PA.

1939 Water Rights Act

This statute requires all public water suppliers to obtain a permit from the state Department of Environmental Protection before diverting or withdrawing surface waters for a service area.

With respect to public water supply, Pennsylvania’s Public Utility Commission (PUC) regulates public water systems (serving 25 or more customers year-round), including bottled water suppliers. The extent of regulation applies to service areas, and does not address the quality of water delivered. In the event a public water supplier chooses to discontinue service for an area, prior approval of the PUC is required. Public water supply systems are regulated under the state Safe Water Drinking Act with regard to water quality.

Dam Safety and Encroachment Act

The state DEP regulates all aspects of dam construction and management within PA. Before constructing, maintaining, abandoning, or enlarging a reservoir, a permit must be issued by the agency. “Water obstructions” as defined in the statute include dikes, bridges, culverts, walls, fill, piers, wharves, and embankments, and require a permit from the Department before any work can commence.

In addition to regulating reservoirs, the Act establishes guidelines for minimum releases and maintaining minimum flows in streams below reservoirs. Furthermore, the statute provides the regulatory framework for activities affecting wetland areas including filling in, draining, and inundating these areas. A permit is required from the agency for such activities.

Pennsylvania leads the country in dam removals, many of which are not used for flood control or drinking purposes. In 2016, the state removed ten dams.

Stormwater Management Act

Pennsylvania’s Stormwater Management Act (Act 167) is enforced at the county level and requires each county to adopt a management plan for each watershed within the county for surface water runoff during extreme rain events. In general, once a plan is created they are incorporated into the local zoning ordinance for a municipality. Because these plans are implemented at the local level, a general statewide template does not exist, and plans are highly variable from one county to the next.

The Clean Streams Act

Similar to the federal Clean Water Act, Pennsylvania’s Clean Streams Law contains many of the same provisions as the federal statute and serves as the primary mechanism for regulating the discharge of pollutants into the Commonwealth’s waters. Because the state statute is almost identical to the federal Act, EPA has delegated authority of enforcing the federal statute through Pennsylvania’s DEP via the Clean Streams Law. Many of the standards in Pennsylvania’s law exceed federal minimum standards with regard to regulating water pollution. The statute contains provisions addressing sediment management, erosion prevention, pollution standards, and agricultural operations with respect to runoff. Furthermore, the law gives DEP the power to issue permits for discharging pollutants, storm water permits, and require best management practices for non-point source discharges through best technology requirements and environmental methods.

Acid mine drainage is regulated under the statute and strict provisions allow DEP to closely enforce runoff from these sources into water bodies of the Commonwealth, whether intentional or not.

Water Resources Planning Act of 2002 (Act 220)

Pennsylvania’s Water Resources Planning Act mandates the Commonwealth to develop and adopt a statewide water plan, to be updated every five years. The statute splits the state into six regions (based on watershed boundaries), each tasked with developing their own regional plan for water resources management through a regional committee. Each regional plan is open to a public hearing and must be approved by an overall statewide committee, tasked with developing the statewide plan (incorporates regional plans). This law does not regulate water use; it is meant as a planning and policy guidance document. Water users withdrawing 10,000 or more gallons of water per day, public water suppliers, and hydropower facilities must register and report with the state DEP. Public water suppliers and hydropower facilities, regardless of the amount used, must provide metered use information to the agency. Likewise, water users of 50,000 gallons per day or more must also provide metered information to DEP.

The plan itself has three primary principles: collect and disseminate water resources data, manage water resources in an integrative way (conjunctive management of surface and groundwater), and develop policies encouraging technological advances to conserve water resources. With regard to data, DEP is scheduled to initiate their public database of this information in October 2017. The state plan must contain 16 different elements: varying from an inventory of surface and groundwater resources in each region to assessments of current and future withdrawal needs, flood plain and storm water management problems, and navigation needs. Also included are the identification of critical water planning areas. Critical water planning areas are areas of the Commonwealth where existing or future water demands exceeds the rate of recharge. For each of these areas a Critical Area Resource Plan (CARP) must be developed for all watersheds. Plans include alternatives to ensure a supply of water for current and future uses. Currently, the plan is being updated (last updated in 2009) to include the formation of statewide and regional planning committees and finalizing the CARPs first prepared in the 2009 plan.

Marcellus Shale Development

Beginning in 2008, Pennsylvania began exploring and extracting natural gas in the Marcellus Shale geologic formation spanning from the northcentral part of the state to the southwest. An important component of gas exploration and development is through use of hydraulic fracturing (“fracking”) whereby water is pushed underground at high pressures to fracture shale containing pockets of gas. The technique uses large amounts of water, about 4 million gallons per “frac”, but estimates can range from two to eight million gallons depending on site conditions. With regard to Pennsylvania water management and law, Marcellus development has raised some concerns about water withdrawal, water quality as a result of reinjecting wastewater into underground storage areas or above ground storage ponds, sediment and gravel road concerns from water trucks, and impacts on drinking water to name a few. The SRBC regulates all gas development within the boundaries of the basin and has enacted strict guidelines for energy developers with respect to water management and use. In addition, the agency released a report in 2016 concerning water use and natural gas development for the period of 2008-2013.

Pennsylvania’s Oil and Gas Act regulates aspects of water management, notably in instances where a gas company impacts public or private water supply systems through pollution as a result of energy development. In the event the activities of a company cause diminution in the quality of water, they must restore or replace the affected supply with an alternate source adequate in quantity or quality. This was the case concerning the town of Dimock, PA and Cabot Oil and Gas, whereby Cabot supplied alternate sources of water to area residents after methane became present in drinking water supplies. Cabot has not admitted guilt in the case, but agreed to supply water to residents.

Environmental Management and Instream Flows

Pennsylvania Environmental Rights Amendment

Article I Section 27 of the PA Constitution guarantees to its citizens clean air, pure water, and the preservation of the natural, scenic, historic, and aesthetic values of the environment for present and future generations. The Commonwealth has been delegated trustee of these resources and must maintain them for the benefit of the people. Until recently, the power and reach of this amendment has been unsettled in Pennsylvania courts through use of a narrow three-factor test established in the 1970s (Payne case) and another decision in 2012 theorizing the amendment had broader power than the three-part test (Robinson Twp. case). In June 2017, the PA Supreme Court ruled in Pennsylvania Environmental Defense Fund v. Commonwealth of Pennsylvania the amendment has broad powers and mandates certain actions from the Commonwealth in order to comply with the duties of trustee. The case stemmed from oil and gas royalties being transferred out of the Department of Conservation and Natural Resources Oil and Gas Fund to the General Fund to balance the state budget. As a result of the case, state agencies, such as DEP, must give increased scrutiny to permit application and projects affecting the environment. In addition, the decision binds the Commonwealth in certain ways the natural resources can be managed. Specifically, natural resources in the state must be managed primarily from the viewpoint for the public benefit. The future reach of this decision and the amendment remains to be seen, but the case has definitively broadened its power.

Chesapeake Bay

The EPA established the Chesapeake Bay Total Maximum Daily Load (the “Bay TMDL”) on December 29, 2010. Despite nearly 25 years of previous efforts and voluntary agreements between the Bay watershed states, insufficient progress resulted in continued poor water quality in the Bay and its local tributaries. The Bay TMDL includes comprehensive measures to drive restoration of the water quality in the Bay and is the largest ever developed by the EPA, covering a 64,000-square-mile watershed. The standard sets out the required reductions of nitrogen, phosphorus and sediment across the Bay states that are necessary to meet the Bay’s established water quality standards.

The Bay TMDL is unique in that it is made up of 92 smaller TMDLs for individual Chesapeake Bay tidal segments. These are all placed into the accountability framework of Watershed Implementation Plans (“WIPs”), which are prepared by the individual Bay states (Delaware, Maryland, New York, Pennsylvania, West Virginia and the District of Columbia). These WIPs outline the steps that these jurisdictions will take in order to meet their TMDL-mandated pollution reductions. Altogether, the Bay TMDL set watershed-wide limits of 185.9 million pounds of nitrogen, 12.5 million pounds of phosphorus and 6.45 billion pounds of sediment per year. This is roughly equivalent to a 25 percent reduction in nitrogen, 24 percent reduction in phosphorus and 20 percent reduction in sediment.

The Bay TMDL requires that all control measures necessary to fully restore the Bay and its tidal rivers are in place by 2025. It also calls for all of the practices necessary to achieve 60 percent of the overall nitrogen, phosphorus and sediment reductions to be in place by 2017.

Instream Flows

Pennsylvania does not have a statewide instream flow program; however, designated flow targets have been developed in select cases. The SRBC completed a study in 1998 regarding flow targets in Maryland and Pennsylvania for trout habitat. This study is the basis the agency uses in managing waterbodies within the basin boundaries. Other partners on the report include the state DEP, Fish and Boat Commission, and Army Corps of Engineers. In addition to the SRBC study, the Dam Safety and Encroachments Act establishes guidelines for minimum releases and maintaining minimum flows in streams below reservoirs. In addition to DEP and SRBC, the PA Fish and Boat Commission and DRBC both regulate flows for specified waterbodies within the Commonwealth.

Drought and Floods

According to a recent flood report from Penn State University, Bucknell University, and Florida Gulf Coast University, flooding is the most frequent and catastrophic natural disaster in Pennsylvania. According to the report, about 6.5% of PA residents reside in floodplains. Rising flood insurance rates and premiums have made it difficult for citizens within the Commonwealth to sell homes. Currently, PA does not have a comprehensive floodplain management program addressing flooding and storm water.

The Pennsylvania Emergency Management Agency (PEMA) is responsible for managing drought in the Commonwealth, through support of the state DEP. The Secretary of DEP assigns a Drought Coordinator who works closely with the Drought Task Force comprised of state, federal, and interstate agencies. DEP’s Office of Water Resource Planning is the lead entity for drought management and monitoring. Most water conservation measures are conducted at the county level. Both DEP and PEMA manage drought through a three-pronged approach. Drought can be classified as a Watch, Warning, or Emergency. Within each classification certain water users may be curtailed and a number of water conservation measures are implemented. In a drought emergency, each public water supplier is mandated to have a drought contingency plan with appropriate response actions. More information on drought management in the Commonwealth can be found at:

Water Market

Pennsylvania does not have a statewide water market.


Pennsylvania is a signatory to a number of interstate water compacts. As previously mentioned, the Commonwealth is a party to the Delaware River Basin Compact and Susquehanna River Basin Compact.

In addition to the two river basin agreements, PA is a party to the Great Lakes-St. Lawrence River Basin Water Resources Compact. The agreement includes the eight Great Lakes states and voluntary participation from two Canadian provinces. The agreement aims to consistently manage the waters of the Great Lakes, as well as, protect water quality in the lakes. Applying to both surface and groundwater sources, all diversions of waters within the Great Lakes Basin are prohibited (with a few exceptions) to areas outside the Basin boundaries, unless parties to the agreement agree to such a transfer.

About the Author

Bob Caccese is a Staff Attorney with Penn State Law, active in water law and policy, fisheries, and wildlife matters. He received his B.S. in Wildlife and Fisheries Science from Penn State University and J.D. from Penn State Law. He is a member of Trout Unlimited, the American Water Resources Association, and American Bar Association.

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