Path of Urban Runoff

Rain and excess water from homes and businesses¬†“known as urban runoff” flow into gutters, down storm drains and through pipelines directly to ponding basins, canals, creeks or rivers. In these basins and waterways, runoff percolates through soil and into groundwater.

Storm Drain System

The water that goes down storm drains travels directly to our ponding basins untreated. The water carries with it debris and pollutants that are picked up along the way as it flows through residential yards, sidewalks and streets. Not over-fertilizing lawns, not using pesticides excessively, not dumping pollutants in the gutter or down storm drains and being mindful of litter helps keep the storm drain system clean and working properly.

The sewer system should not be confused with the storm drain system. A separate underground network of pipes carries water from the inside of our homes and businesses to a treatment facility. Once the wastewater is cleaned, it is released to groundwater recharge ponds or irrigation canals to be used for saline-tolerant crops, such as alfalfa and cotton.

The Fresno Metropolitan Flood Control District has produced a video that details the storm drain system and how residents impact storm water quality. To request a free copy, call (559) 456-3292 or e-mail