Pollution Prevention

Pollution prevention is the least expensive category of stormwater practice a community can deploy, because it intercepts pollutants before they ever reach a pipe, pond, or filter. Every structural practice in a watershed — every pond, wetland, and bioretention cell — treats runoff after it has already picked up its load of nutrients, metals, hydrocarbons, sediment, chloride, and bacteria. Source control works one step earlier: it changes the everyday municipal operations, business practices, and household habits that put those pollutants on the pavement in the first place.

The fact sheets in this section cover the full source-control toolbox for a municipal stormwater program. They fall into three broad groups: practices a public-works department carries out directly (catch basin cleaning, street sweeping, storm drain maintenance, salt management), practices that target commercial and fleet operations (fueling, loading docks, spill response, vehicle maintenance), and practices that depend on resident behavior (car washing, lawn care, pet waste, septic care, used oil disposal). Each sheet describes the pollution pathway, the operative recommendations with real costs and frequencies where they are documented, implementation notes for program managers, and what the available monitoring data say about effectiveness. To translate the pollutant concentrations discussed throughout these pages into annual loads for a specific drainage area, use the Simple Method runoff calculator.

Municipal operations

Commercial and fleet operations

Residential behavior

How to use these fact sheets

Program managers assembling a stormwater plan rarely fund every practice at once. A defensible sequence starts with the municipal operations group — those practices run on equipment and budgets the public-works department already controls, and they demonstrate good faith under an MS4 permit. Commercial practices follow, typically attached to inspection programs and industrial permit requirements. Residential outreach comes last not because it matters least, but because behavior change takes the longest to show results and works best once the municipality can point to its own housekeeping as the example. Communities that monitor before and after implementation consistently find that no single source-control practice transforms water quality on its own; the value is cumulative, and the cost per pound of pollutant prevented is usually far below the cost per pound removed by structural treatment.