Drinking Water Quality Standards in the United States

When you pour some cool tap water into a glass on a warm fall afternoon, enjoy a shower after a long day of work or throw a load of clothes in your washing machine, chances are that you are not thinking about the quality of your water. And that’s the goal. Teams of highly skilled water quality experts at your local water agency regularly test your water thousands of times per year to ensure that it is meeting some of the highest water quality standards in the world before it comes to your home.

Whether you live in New York or right here in California, the quality of your water is governed by the United States Environmental Protection Agency Safe Drinking Water Act, which requires all public water systems to notify customers annually regarding the quality of the water they receive. In addition, each state has stringent standards for water that each water agency must adhere to.


Here are four more reasons why tap water quality can be trusted

Reason #1: Tap water beats out bottled water when it comes to safety

In fact, tap water that comes to our home undergoes many more tests than bottled water. That is because of the national Safe Drinking Water Act, which requires water agencies to conduct extensive water quality testing by certified laboratories. Our drinking water is not only regulated by the national Safe Drinking Water Act but also is regulated by the State Water Resources Control Board – Division of Drinking Water (DDW). Conversely, bottled water does not need to meet these same rigorous standards, is often tested less frequently than tap water and the leaching of the plastic bottle the water comes in is not tested.

Reason #2: Water quality is transparently communicated

Each year before the water reaches your tap, it is tested and treated thousands of times to ensure that it meets or surpasses rigorous state and nationwide water-quality standards. These results are legally required to be shared annually with customers by mail or online. The reports for the prior year are available after July 1 and provide customers with detailed information on the quality of their drinking water, including how much lead and copper is in the water, special health concerns, public health goals and maximum contaminant levels.


Reason #3: Investments in water technology and treatment

Water agencies are constantly adopting the latest technology and treatment options to monitor the quality of your water. For instance, when it comes to groundwater Orange County Water District (OCWD) has become the first public agency laboratory to achieve state certification to analyze per- and polyfluoroalkyl substances (PFAS).

As technology for testing continues to improve, it allows water agencies to detect and treat for substances, such as PFAS, at a faster rate. “We continue to proactively monitor and protect our groundwater supply and look for ways to assist our regional producers with opportunities to provide some of the cleanest drinking water in the world,” said OCWD’s Executive Director of Water Quality & Technical Resources Jason Dadakis.

Reason #4: Water has Set Maximum Contaminant Levels and Public Health Goals

The EPA sets maximum contaminant levels (MCL) for drinking water to keep water safe. When contaminants in water exceed the MCL, this information must be reported to customers and the state. It is also noted in the annual Water Quality Report.

Public Health Goals, on the other hand, are set by the state and established based on extensive testing – even studying the impacts on people who have been exposed to certain contaminants. While these goals are instrumental in guiding drinking water laws and protecting human health, it is important to note they are not legal limits. A whole team of experts works together to determine Public Health Goals, including toxicologists, epidemiologists, physicians, biostatisticians and research scientists.

There are numerous tests our water goes through to ensure it meets in-depth water quality testing before making its way to our homes. For questions about your water agency’s water quality report, visit their website or contact them to receive a copy.