Pennsylvania’s tap water is generally safe to drink, especially for the approximately 80% of residents served by public water systems, which are subject to rigorous federal and state oversight. Water safety is not uniform across the Commonwealth, depending heavily on the specific source, the age of the local infrastructure, and whether the supply is public or private. While public systems operate under strict mandates, localized challenges exist, particularly concerning emerging contaminants and aging pipes. Understanding the safety of your water supply requires investigating the particular risks relevant to your area and water source.
Oversight and Standards for Public Water Systems
Public water systems in Pennsylvania are heavily regulated under the framework of the federal Safe Drinking Water Act (SDWA). The U.S. Environmental Protection Agency (EPA) sets national standards, known as Maximum Contaminant Levels (MCLs), for hundreds of substances. These regulations establish the baseline safety requirements that all public water utilities must meet.
The Pennsylvania Department of Environmental Protection (DEP) handles the state-level implementation and enforcement of these federal rules. The DEP’s Bureau of Safe Drinking Water manages the program, overseeing approximately 9,200 public water systems. This state authority, known as “primacy,” ensures that enforcement activities are tailored to Pennsylvania’s specific environmental conditions.
Public water utilities must perform routine and frequent testing for a wide range of contaminants, including microbiological, chemical, and radiological substances. The frequency of this mandatory testing is determined by the specific substance and the size of the population served. This comprehensive testing schedule provides assurance that the water being delivered meets all health-based standards before it reaches the consumer.
Key Contaminants Affecting Pennsylvania Water Sources
Despite robust regulatory oversight, Pennsylvania faces specific contamination issues due to its industrial history and geology. Lead contamination remains a persistent concern, originating primarily from older service lines and household plumbing, not the source water. Lead can leach into the water when it passes through pipes, fixtures, and solder, especially in homes built before 1986.
A widespread concern is contamination by Per- and Polyfluoroalkyl Substances (PFAS), often called “forever chemicals.” These synthetic chemicals are found near industrial sites, military bases (where they were used in firefighting foams), and landfills. The DEP has established state-specific Maximum Contaminant Levels for two common PFAS compounds, PFOA and PFOS.
Agricultural runoff represents another source of contamination, particularly in rural areas, leading to elevated levels of nitrates and pesticides. High nitrate levels pose a specific health risk to infants, potentially causing a condition called methemoglobinemia. These contaminants result from fertilizer and pesticide application on farmland, which then enters the water supply.
The Critical Distinction of Private Wells
Unlike public water systems, private wells serving individual households in Pennsylvania are not regulated by the EPA or the DEP. The approximately one million residents who rely on private wells are entirely responsible for their water quality, as no mandatory testing or treatment requirements are imposed.
Private wells face distinct, localized risks. Bacterial contamination, such as E. coli and total coliform bacteria, is frequently detected, indicating potential contamination from septic systems or surface runoff. Research has shown that a significant percentage of private wells do not meet at least one safe drinking water standard, often due to bacterial presence.
Other contaminants unique to private well water include volatile organic compounds (VOCs) and naturally occurring radon. VOCs can enter groundwater from nearby industrial activities or leaking underground storage tanks. Radon, a colorless, odorless radioactive gas, can dissolve into groundwater from the surrounding geology, posing a risk when released into the air during water use.
Understanding Your Water Quality Report and Mitigation Options
For residents on a public water system, the primary tool for investigating water quality is the Consumer Confidence Report (CCR). Utilities must deliver the CCR annually by July 1st. The report details the water source, the contaminants detected, and how the results compare to regulatory standards set by the EPA and DEP. Large utilities must also post their most current CCR on a publicly-accessible website.
If the CCR or concerns about a private well indicate a potential problem, third-party testing by a state-accredited laboratory is the next recommended step. Testing should be tailored to specific concerns, such as testing for bacteria annually for private wells or testing for lead in older homes. The DEP maintains a list of accredited labs that provide reliable, scientific analysis of a water sample.
Mitigation options depend on the contaminant but generally involve point-of-entry or point-of-use filtration systems. A carbon filter is effective for improving taste and odor, and removing chlorine and many VOCs. For serious contaminants like lead, nitrates, or PFAS, a reverse osmosis (RO) system or an NSF-certified granular activated carbon (GAC) filter installed at the tap is the most effective solution.