Tap water in the United States is generally considered safe for consumption due to a robust framework of regulations and treatment processes. This widespread safety results from continuous monitoring and adherence to established guidelines designed to protect public health. Understanding these systems provides clarity regarding water quality.
National Standards and Oversight
The Environmental Protection Agency (EPA) primarily oversees public drinking water safety in the U.S. The Safe Drinking Water Act (SDWA), passed by Congress in 1974, is the principal federal law ensuring safe drinking water for the public. This legislation grants the EPA authority to set national standards for drinking water quality.
The EPA establishes National Primary Drinking Water Regulations (NPDWRs) that set legally enforceable maximum contaminant levels (MCLs) for substances that may adversely affect public health. These regulations cover a wide range of contaminants, including microorganisms, chemicals, and radionuclides. Public water systems are required to regularly monitor their water for these contaminants. Over 92% of the population served by community water systems consistently receives drinking water that meets these health-based standards.
From Source to Tap
Water’s journey from its natural source to your tap involves a series of treatment processes designed to remove impurities and ensure safety. It typically originates from surface sources like rivers and lakes or from groundwater aquifers. Raw water is then transported to a treatment plant where it undergoes several stages of purification.
A common sequence of treatment steps includes coagulation, flocculation, sedimentation, filtration, and disinfection. Coagulation involves adding chemicals to clump suspended particles, forming larger masses called floc that settle during sedimentation. Filtration then removes remaining impurities by passing water through layers of materials like sand and charcoal.
The final step is disinfection, often achieved by adding chlorine or chloramine to eliminate any remaining harmful bacteria, viruses, and parasites. Disinfection also provides a residual effect, protecting the water from germs as it travels through the distribution system. This multi-stage process, combined with robust infrastructure, ensures the delivery of clean water.
How to Check Your Local Water Quality
Individuals can access information about their local tap water quality through annual Consumer Confidence Reports (CCRs), also known as Water Quality Reports. The EPA mandates that most community water systems provide these reports to customers annually by July 1. These reports are designed to be informative and transparent, helping consumers understand their drinking water quality.
A CCR typically details the source of the drinking water, such as rivers, lakes, or groundwater wells. It also includes a table listing any contaminants detected, their concentrations, and whether these levels meet federal and state safety standards. Key terms like Maximum Contaminant Level (MCL), the highest allowed, and Maximum Contaminant Level Goal (MCLG), a non-enforceable health goal, are defined to help interpret the data. The report will also indicate if any drinking water regulations were violated and explain corrective actions taken.
Most water suppliers publish their CCRs online, often accessible through their official websites. If you do not receive a copy in the mail, you can typically find it on your community’s website, by calling your local water department, or by using EPA’s online CCR search tool. Local health departments can also be a resource for alerts or further information regarding water quality in your area.
Common Concerns and Solutions
Even when tap water meets all safety standards, consumers may have concerns regarding its aesthetic qualities, such as taste, odor, or hardness. Chlorine, used for disinfection, can sometimes leave a noticeable taste and smell. Running cold water for a few minutes, chilling it, or using an activated carbon filter can help reduce chlorine taste and odor. Boiling water for about 15 minutes can also cause chlorine to evaporate.
Hard water, characterized by high levels of minerals like calcium and magnesium, is another common issue. While not a health concern, hard water can lead to mineral buildup in pipes and appliances and may have a metallic or chalky taste. Water softener systems can effectively reduce hardness by exchanging these minerals with sodium or potassium ions.
Lead contamination, while rarely originating from the source water itself, can enter tap water from older plumbing materials, such as lead pipes, fixtures, or solder, especially in homes built before 1986. The EPA has set a maximum contaminant level goal for lead at zero, emphasizing that no amount of lead is considered safe. Solutions include running cold water for a few minutes, especially if it has been stagnant, and using filters certified to remove lead. Point-of-use filters, like reverse osmosis systems or carbon filters, are effective at removing lead from drinking water.