How is Urban Runoff Affecting Your Water Quality?

Urban and suburban areas contain buildings, homes, and other impervious (non-porous) surfaces, such as paved roads and parking lots, that do not allow stormwater to absorb into the ground thoroughly. 

Instead, we rely on built ‘gray’ infrastructure, like stormwater drains, which carries the water out of (sub)/urban areas and back into our waterways, such as rivers, streams, lakes, etc. where it often enters the waterways with excessive force. This increases bank erosion along our waterways which jeopardizes streamside vegetation and aquatic habitat.

“Did you know that because of impervious surfaces like pavement and rooftops, a typical city block generates more than 5 times more runoff than a woodland area of the same size?” (EPA, 2003).

In urban settings, where there is less natural ground cover to absorb and filter pollutants, they are carried more quickly to our waterways. A few examples of these contaminants include:

  • Excess pesticides and nutrients (nitrogen and phosphorus) from lawns/gardens
  • Litter
  • Oil, grease, or other toxic chemicals from motor vehicles
  • Viruses, bacteria, and nutrients from animal waste or failing septic systems
  • Sediment
  • Road salts
  • Heavy metals from roof shingles, motor vehicles, factories, construction sites, and other sources.

A stormwater outfall in Anne Arundel County dumping into South River

These pollutants can harm fish and other wildlife, disturb native plant species, contaminate our drinking water, as well as make recreational areas unsafe. Two forms of urban runoff exist; point source and nonpoint source pollution.

Point source includes any source that directly dumps pollution into our waterways, such as a specific pipe from a sewage treatment plant, factory, or a home. Nonpoint source pollution is harder to identify as it does not enter the waterways directly, it is carried into by rainfall or snowmelt. Typical sources of nonpoint pollution include precipitation, drainage, seepage, or runoff from farms, lawns, or pavements.

Simple ways you can you make a difference for clean water

Fortunately, there are simple actions we can take within our urban neighborhoods to reduce pollution before it enters our waterways. Implementing native vegetation in our communities (such as shrubs, trees, or other plants) aids in the absorption of excessive runoff and reduces pollution. Urban citizens should also be sure to check under motor vehicles for leaks of oil or other toxic fluids that may end up as a source of pollution in our waterways. Businesses and homeowners can sweep up debris instead of washing it ‘away’ with a hose, as the debris can clog stormwater drains which limit their functionality. For those who utilize a septic tank system, ensure that it is professionally inspected and pumped every three to five years to ensure that it is not seeping into our waterways.

By using nitrogen and phosphorus-intensive fertilizers sparingly at our homes and farms, we can reduce the amount of excess nutrients entering and polluting our waterways. This is beneficial because nutrient pollution promotes the growth of algae within our waterways, which as the algae decompose, can lead to hypoxic conditions (oxygen-depleted water), resulting in harm or death to aquatic life and contamination of our drinking water.

Mississippi River Carrying Sediment Creating Algal Bloom in the Gulf of Mexico. Image shot 2007. Source: NASA/Landsat/Phil Degginger / Alamy Stock Photo


Lend your voice! Further ways to support clean water

At 1 Mississippi, we advocate for expanding the use of natural (green) infrastructure. Examples of natural infrastructure include reconnecting floodplains and restoring wetlands and marshes (which have porous surfaces) which slow and store water and filter harmful pollutants from our waterways. In addition, natural infrastructure creates habitat, promoting the livelihood of wildlife, and creating recreational activities.

You can take immediate action to improve our water quality by signing our petitions below:

Expanding the use of natural infrastructure

Reducing nutrient pollution

Nutrient pollution in the Mississippi River Basin negatively impacts drinking water for over 20 million people and is fueling the annual Gulf of Mexico Hypoxic ‘Dead Zone’. Take action today!


-Kristen Mertz, 1 Mississippi IL/MO Regional Outreach Coordinator


Can the River count on you? Become a River Citizen today!




Become a

River Citizen

Yes! The River can count on me!

I am committed to protecting the Mississippi River and will take at least three actions to care for this valuable resource. Please keep me informed about actions I can take to protect the Mississippi River as a River Citizen:

Step 1

Become a River Citizen

Yes! The River can count on me!

I am committed to protecting the Mississippi River and will take at least three actions to care for this valuable resource. Please keep me informed about actions I can take to protect the Mississippi River as a River Citizen:


Step 2

Educate Yourself

One goal for 1 Mississippi is to educate the public on the urgent problems facing the River. We are supported by the Mississippi River Network, a group of organizations that are experts in various areas concerning the River. Each section below is intended to provide some basic knowledge about these important issues and links to experts who can provide more detailed information. 

Nutrient pollution

Importance of floodplains and wetlands

Farm bill conservation programs


Step 3

Take Action

There are many ways you can take action. We have a list of 10 actions you can take now, You can volunteer and you can check our action center in order to see what bigger projects we are working on. Here we give you the information you need to call your congressman or sign onto proposals. You can also check out our events calendar to see what events are happening in your area.

10 actions you can take now!

The Action Center

Events Calendar

River Citizens are people who want to clean up and protect America's greatest River. 

Share This