As winter fades and warmer weather settles across Pennsylvania, lawns green up, gardens return, and outdoor projects begin again. Spring showers and sudden summer thunderstorms are part of the season—but all that rainwater has to go somewhere.

What many homeowners do not realize is that the runoff from heavy rain can carry pollution directly into local streams, rivers, and lakes.

Understanding Stormwater Runoff

In forests and undeveloped areas, rainfall naturally soaks into the ground, where soil and plant roots help filter it. In developed neighborhoods, however, water hits hard surfaces such as rooftops, roads, sidewalks, and driveways. These “impervious surfaces” prevent rain from being absorbed naturally.

Instead, water rushes across pavement and into storm drains, collecting pollutants along the way.

In many Pennsylvania communities, storm drains discharge directly into nearby waterways without the same treatment process used for household wastewater. That means anything washed into the street may eventually end up in the creeks, rivers, and reservoirs our communities depend on.

Everyday Activities That Pollute Stormwater

Many common spring and summer routines can unintentionally contribute to water pollution.

Lawn Fertilizers and Weed Killers

Applying more fertilizer than your lawn can absorb allows excess nutrients to wash away during storms. This can contribute to harmful algal growth and lower oxygen levels in waterways, stressing fish and aquatic life.

Grass Clippings and Leaves

Blowing yard waste into the street may seem harmless, but it can clog storm drains and increase localized flooding. As organic debris decomposes in streams, it also reduces water quality.

Vehicle Washing and Fluid Leaks

Soap, oil, antifreeze, and other automotive fluids can be harmful to wildlife and aquatic ecosystems when washed into storm drains.

Pet Waste

Pet waste left on the ground can release bacteria and parasites into local waterways after rainfall, affecting recreational waters and public health.

Simple Ways to Reduce Stormwater Pollution

Protecting Pennsylvania’s waterways does not require major changes. Small actions at home can make a meaningful difference.

1. Mow Higher

Keeping grass around 3 to 4 inches tall encourages deeper root growth, helping soil absorb rainfall more effectively and slowing runoff.

2. Create a Rain Garden

Rain gardens are shallow landscaped areas filled with native plants that temporarily collect runoff from roofs or driveways. They help water soak into the ground naturally while filtering pollutants.

3. Use a Rain Barrel

Rain barrels connected to downspouts capture runoff before it reaches the street. The stored water can later be used for gardens and landscaping during dry weather.

4. Wash Cars Responsibly

Whenever possible, wash vehicles on gravel or grass rather than pavement so water can filter through the soil. Commercial car washes are another good option because many recycle or treat their wastewater.

5. Apply Fertilizer Carefully

Before applying fertilizer, consider testing your soil to determine whether it is actually needed. Avoid applying products before heavy rain, and sweep stray granules back onto the lawn instead of leaving them on pavement.

Protecting Pennsylvania’s Streams Starts at Home

Pennsylvania’s rivers and streams—from the Susquehanna to the Delaware and Allegheny—are valuable natural resources that support recreation, wildlife, and drinking water supplies.

By making smarter choices around our homes and yards during the rainy season, we can help reduce flooding, improve water quality, and preserve healthy waterways for future generations.

Because in the end, storm drains are meant for rainwater—not pollution.