Stormwater Division

Stormwater Runoff

Stormwater runoff is the water that flows off City sidewalks, streets, and other hard surfaces during rainstorms. The runoff is collected in ditches, culverts, catch basins, and storm sewers.

In areas with natural ground cover, only 10% of rainwater becomes runoff. The rest is absorbed or evaporates. In urban areas, up to 55% of rainfall can become storm water runoff.

A storm drain maintenance program is required to ensure that ditches, culverts, catch basins, and storm sewers are kept clean of sand, silt, and other debris that may plug the system.

How You Can Help....

  • Don't litter! This means you should never throw any trash on the ground. When it rains the litter washes into the storm drains and creates issues.
  • Keep your leaves and grass clippings out of the streets so that they do not end up washing into the storm drain inlets.
  • Lawns need less than an inch of water per week. If it rains an inch, do not water. Water that runs off yards can go to storm drains. 
  • Never dump anything down a storm drain inlet.
  • Wash your vehicles on your lawn or at a car wash facility instead of in your driveway or follow one of these environmentally friendly car washing methods.  

Reporting Discharges

To report a suspected illicit discharge in Sunnyside, call (509) 837-5206.

Learn More

To learn more about stormwater check out the Regional Stormwater Management Program.

Send Us Your Comments

If you would like to make comments on the City's Stormwater Management Program Plan please email us at