A beach advisory leaves it up to users as to whether they wish to risk going into the water. In the case of a beach closure, the state and/or local government decides that water conditions are unsafe for swimmers and other users.
How can beach-goers avoid the disappointment of arriving at their summer vacation destination only to find that authorities advise them not to swim there or that the beaches are closed altogether?
Unfortunately, there is no central database that provides information on beach closures and advisories in real time. The best way to find information on the current water quality of a particular beach is to plan ahead.
In some cases, warning signs will be posted to alert people of the potential risk of illness from contact with the water. Signs may be placed for short-term problems or more permanent ones, when, for example, repeated monitoring indicates ongoing contamination.
Common culprits leading to beach closures and advisories include excessive rainwater that carries pollution from storm drains (like motor oil, pet waste, pesticides, trash, and pathogens) to recreational waters; “red tides” and other harmful algal blooms; and sewage and chemical spills from known sources. It is generally wise to avoid swimming after heavy rains or if the water is an unusual color without first checking with local or state health authorities.
In the Gulf of Mexico, NOAA's Harmful Algal Bloom Operational Forecast System identifies potentially harmful blooms of the toxic alga Karenia brevis, where the blooms are, how big they are, and where they are likely to go. The toxins produced by the algae become airborne when waves break along the beach during a bloom, causing eye, throat, and nose irritation in most beach-goers, but more severe reactions in people with asthma and other respiratory issues.
Forecasts are distributed through conditions reports and bulletins. Conditions reports, which include forecasts of potential levels of respiratory irritation associated with blooms of the alga K. brevis in the near-term, are posted twice a week after confirmation of a HAB, and once weekly during the inactive HAB season. Additional bloom analysis is included in harmful algal bloom bulletins that are emailed to a subscriber list of state and local coastal resource managers, public health officials, and researchers. In many cases, NOAA's harmful algal bloom data contribute to authorities’ decision to post a beach closure or advisory.
The Beaches Environmental Assessment and Coastal Health (BEACH) Act addresses contaminants in coastal recreational waters. The BEACH Act set national water quality monitoring and reporting standards, creating uniformity throughout the nation that did not exist prior to its passage. States, tribes, territories, and local governments decide whether to close or reopen a beach, and are required to report the information to the U.S. Environmental Protection Agency.