Prior to the SDWA there were few national enforceable requirements for drinking water. In 1914 the U.S. Public Health Service (PHS) published a set of drinking water standards, pursuant to existing federal authority to regulate interstate commerce, and in response to the 1893 "Interstate Quarantine Act." As such the standards were directly applicable only to interstate common carriers such as railroads. For local drinking water utilities, these standards were basically recommendations and not enforceable requirements. However, many municipal utlities began to voluntarily adopt the standards.