Faucet water, readily available in homes and communities, serves as a fundamental resource for drinking, cooking, and hygiene. This widespread access is possible because public water systems implement extensive processes to treat and purify water from various natural sources. These rigorous treatments are designed to ensure the water delivered to your tap is safe for consumption and meets established quality standards.
From Source to Tap
The water flowing from your faucet originates from either surface water or groundwater sources. Surface water includes large bodies like lakes, rivers, and reservoirs, which collect precipitation and runoff. Approximately 70% of the population in the United States receives water from surface sources.
Groundwater, on the other hand, is collected from underground aquifers and wells. These underground reservoirs are replenished by rain and surface water that filters through the ground. Once collected, this raw water is transported through a network of pipes to treatment facilities.
Making Water Safe to Drink
Water undergoes a series of purification steps at treatment plants to remove impurities. This multi-stage process typically begins with coagulation, where chemicals are added to the water to bind small particles together, causing them to clump into larger, heavier particles called flocs.
Following coagulation, the water enters a flocculation stage, involving gentle mixing to encourage these flocs to grow larger. Sedimentation then allows these heavier flocs to settle to the bottom of large basins. The clearer water on top is then moved through filtration systems, often consisting of layers of sand and gravel, which trap any remaining fine particles, turbidity, and algae. Disinfection, where chemical disinfectants like chlorine or chloramines are added to kill harmful microorganisms such as bacteria, viruses, and protozoa. This disinfectant residual also helps protect the water as it travels through distribution pipes to your tap.
Everyday Ingredients in Your Water
Beyond the intentional addition of disinfectants, faucet water naturally contains various substances that are generally harmless and can even contribute to its taste. Minerals like calcium, magnesium, and potassium are commonly present, influencing water hardness and flavor. These naturally occurring elements are picked up as water travels through soil and rock formations.
The disinfectants, primarily chlorine or chloramines, remain in the water at low, safe levels. Chlorine has been used for over a century to prevent waterborne diseases, effectively killing bacteria and viruses. Chloramines, a combination of chlorine and ammonia, are also used and offer longer-lasting disinfection as water moves through the distribution system.
Understanding Potential Contaminants
Despite rigorous treatment, various substances can sometimes be found in tap water, raising concerns about potential health impacts. Heavy metals like lead and copper can enter drinking water, often from the corrosion of aging pipes and plumbing fixtures. Lead service lines, solder used before 1986, and brass faucets are common sources of lead, which can be particularly harmful to children. Copper can also leach from pipes.
Microorganisms, such as certain bacteria, viruses, and protozoa like Cryptosporidium and Giardia, are typically removed during treatment. However, they could potentially enter the water supply if there are infrastructure failures or breaches in the distribution system. Chemical contaminants also pose a risk; nitrates, often from agricultural runoff, septic systems, or industrial waste, can be present, with high levels being a concern for infants. Pesticides, industrial chemicals, and trace amounts of pharmaceuticals can also find their way into water sources.
Disinfection byproducts (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), form when disinfectants react with naturally occurring organic matter in the water. While disinfection is necessary for public health, these byproducts can be a concern with long-term exposure. An emerging contaminant is microplastics, tiny plastic particles that can enter water sources from surface runoff, wastewater, and the breakdown of plastic waste. Their presence in drinking water is an area of increasing study.
Protecting Your Tap Water Quality
The U.S. Environmental Protection Agency (EPA) establishes national standards for drinking water quality under the Safe Drinking Water Act (SDWA). This federal law mandates that public water systems meet specific health-based standards for over 90 contaminants. States and local water suppliers are responsible for implementing and overseeing these standards.
Consumers can access important information about their local water quality through annual Consumer Confidence Reports (CCRs), which public water utilities are required to provide. These reports detail the water’s source, detected contaminants, and compliance with regulatory standards. For those with specific concerns or preferences, home water testing kits can provide insights into their tap water’s composition. Additionally, various home filtration methods, including pitcher filters, faucet-mounted filters, and whole-house systems, are available to further reduce certain contaminants or improve taste.