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What is Stormwater Pollution
What Causes Stormwater Pollution?
Effects of Stormwater Pollution
What You Can Do

What is Stormwater Pollution?

Storm water runoff is one of the leading causes of pollution in our surface waters. In fields and forests, most rain is absorbed by the soil or is taken up by plants and trees. Rainwater that flows overland is called storm water runoff. However, developed urban areas contain many impervious surfaces like roofs, parking lots and streets. This increase in impervious coverage can cause both water quantity and quality problems. The added impervious coverage prevents rain from infiltrating into the ground and concentrates the runoff so that most of the water rapidly runs off the property and into storm drain systems, creeks or the ocean in unnaturally large amounts.

Storm water can quickly become polluted by picking up chemicals, fertilizers, soil, and litter while traveling overland. Even small amounts of pollutants that accumulate on roads, parking lots, and sidewalks can be transported into nearby streams, rivers, wetlands, and the ocean potentially causing water quality problems. Storm water pollution is non‐point source pollution, meaning the sources are varied and spread out. Identifying sources of storm water pollution and keeping them off impervious surfaces or allowing them to be absorbed into plants or the pervious ground (away from storm drains or roadside ditches) is the best and most economical way to keep storm water clean.

What Causes Stormwater Pollution?

Many of our daily activities contribute to storm water pollution. Storm drains are designed to carry clean rainwater into our waterways. They should not be used for a dumping ground for waste liquids and materials. Pollutants get into our streams and coastal water because people have allowed their wastes, contaminated water and rubbish to enter the storm water drains. These drains might be right outside your front gate, in your own backyard or on your farm. Many everyday activities can pollute storm water systems if you don’t keep pollutants away from storm drains.

Activities That Cause Pollution if they Reach Storm Drains:

  • Washing cars
  • Over‐watering lawns
  • Washing out paint brushes
  • Oil or gas leaks from vehicles
  • Unsafe disposal of chemicals, detergents, fertilizers, grease, pesticides
  • Leaking or failing septic systems
  • Hosing or sweeping soils and plant debris into the gutter
  • Illegal cross‐connections of downspouts to the sanitary sewer system

Effects of Stormwater Pollution

Storm water pollution may affect your health when:

  • Drinking water from streams that have received polluted storm water
  • Bacteria and toxins can even enter your body through water activities, such as swimming along posted beaches, especially just after rain
  • Eating contaminated fish from such streams or bay

Storm water pollution affects the environment when:

  • Toxic substances, such as vehicle wastes and paint, poison streams and waterways. Poisoned waterways are unsafe for swimming and  drinking and affect aquatic life
  • Plant material, sewage, and some chemicals starve water of oxygen, choking aquatic and marine life
  • Large amounts of unsightly litter from storm water often ends up in waterways and on our beaches
  • Heavy metals from storm water can accumulate in the tissue of fish and seafood and cause poisoning
  • Bacteria and viruses from untreated human and animal wastes are allowed to drain into natural waterways that can make them unsafe for swimming and drinking
  • Sediments from water blasting, concreting, and earth working operations can affect water clarity and harm aquatic life

What You Can Do

Only clean rainwater should enter our storm drains and creeks. Here is what you can do to help keep contaminates out of the water:

  • Make sure that any contaminated water from your house doesn’t enter the storm drains or local creek or that any of your downspouts are connected to your sanitary sewer
  • Wash your car on the lawn so that soapy water and dirt don’t enter the storm water drains, and wash your water‐based paintbrush at the inside sink or on the lawn or garden
  • Clean up any spills or dirt around the home by soaking up the mess or sweeping it. Don’t just wash it down the storm water drain
  • Store chemicals in a safe place
  • Don’t pour unwanted paint, oil or any other substance down the storm water drain. Dispose of them responsibly through the County’s Household Hazardous Waste division (HHW). Visit HHW page for more information or contact them at 831‐454‐2606.
  • Check your vehicle for leaks and recycle used motor oil and antifreeze
  • Use porous pavement or pavers instead of concrete or asphalt if possible
  • Use fertilizers sparingly
  • Maintain and fix your septic system as necessary


Flood Control & Stormwater

701 Santa Cruz, Room 410
Santa Cruz, CA 95060
(831) 454‐2160

8:00 a.m. to 12:00 p.m.
1:00 p.m. to 5:00 p.m.

Email Public Works

Kent Edler
Assistant Director
Special Services

Mark Strudley
Senior Civil Engineer
Flood Control

Rachel Fatoohi
Senior Civil Engineer