Federal flow control refers to the effort by the U.S. Congress to enact legislation overriding the Commerce Clause of the U.S. Constitition with regard to the transport of waste. Today the Commerce Clause prevents states from limiting the importation of garbage from high-exporting states like New York. However, the Commerce Clause does not prevent counties and other municipalities from requiring all local waste be managed in publicly owned facilities. This is local flow control. Localities thus have the power to bar private waste facilties from managing any local waste. This ensures local government will have the benefit of a dedicated waste stream that, through user fees, can finance public works like waste management.
Municipal flow control laws are authorized as a result of the U.S. Supreme Court United Haulers decision in April, 2007. Under the decision, while garbage is an article of interstate commerce, public waste management facilities are held to a more liberal standard than private facilities. Considering the traditional role municipalities play in providing waste management, a municipal law requiring all waste generated locally to be managed at publicly owned facilities results in "even-handed" discrimination against both in-state and out-of-state private business and will ordinarily be allowed.
The Supreme Court found there are compelling local safety interests in taking control of all local waste management. This is an important tool to fend off predatory lawsuits to force communities to host private landfills.