Frequently Asked Questions About Stormwater Runoff and Polluted Runoff

What is stormwater and polluted runoff?

Stormwater runoff is much like it sounds: The water that results from storms and runs off into other areas rather than getting absorbed into the ground. The runoff can come from either rain or melted snow and ice. Less developed areas tend to see less stormwater runoff than highly developed and urban areas because there’s more ground for the water to soak into before running off. When stormwater doesn’t get absorbed by the ground, it tends to flow into creeks and streams.

Polluted runoff is contaminated stormwater that reaches water sources. When natural landscapes are disturbed by new developments, buildings, roads, parking lots, and sidewalks, water from storms no longer has as much ground to absorb it. Instead, stormwater runs off rooftops, down hills, and along sidewalks and roads, picking up just about every pollutant in its path, like litter, oil, and chemicals, before it heads to creeks and streams. Sediment from construction zones and eroded soil from farms and gardens can get carried by stormwater and pollute a body of water and form hazardous sediment at the bottom.

Where does most stormwater runoff eventually end up?

Most stormwater runs into small bodies of water, like creeks and streams, although it will likely head to whatever water source is close by. Eventually, that water will travel to other larger bodies of water, like river, lakes, or oceans. Stormwater runoff can also pool in yards that don’t have slopes for the water to flow from, leading to flooding in and around homes, businesses, sidewalks, and roads. When stormwater picks up dirt, debris, clay, and eroded soil, the mixture can enter bodies of water and form sediment, along with decomposed animals and plants, which eventually pollutes the water.

What causes stormwater runoff to become polluted?

Stormwater runoff becomes polluted when it picks up pollutants, like weed killers, pesticides, and fertilizers. Stormwater can also erode soil and dirt. The polluted runoff can potentially harm the bodies of water it ends up in, along with the animals and plant life living there.

A common source of polluted stormwater runoff is hazardous chemicals in the ground, like fertilizer and pesticides we use around our home. Littering, pet waste and vehicle fluid leaks are other common sources of polluted stormwater runoff. However, seemingly innocent things you might not think are harmful to the environment, like soil, weeds, plant food, and plants themselves, can also contaminate stormwater when it encounters them and pulls them along into nearby water sources. Decomposed plants and animals, farm soil, clay, and dirt are some of the most harmful sources of pollution because they form sediment that settles at the bottom of a body of water and disrupts the natural habitat. If you’ve seen a stream turn cloudy, it’s likely the result of sediment.

Does stormwater pollution only affect small bodies of water, like streams?

Pollution is a widespread issue that has a snowball effect on everything in its path. Water pollution doesn’t just affect a body of water and the plants and organisms that live there; it also affects the larger bodies of water those streams and creeks flow into and anyone, or anything, which depends on it for water and food. Polluted water can kill the fish we eat. Sediment, especially, can cause water to become so contaminated that it’s unsafe to swim in or drink, which not only poses a hazard to businesses and residents that rely on the water, but also to the plants and animals who depend on that water source.

It seems like I’ve heard more about stormwater and stormwater pollution in recent years than in the past. Why is that?

Although stormwater runoff is something that has affected various areas for generations, it’s become more commonly talked about in recent years, mostly because several states have put laws in place to oversee stormwater management. Now, management isn’t something for some well-intentioned home and business owners to do; it’s something that’s required by law.

Laws vary by state and may vary by areas within a state. You can usually check with your county’s offices to learn more about the regulations for your area.

The Clean Water Act, which was put into law in 1972, has also increased public awareness of water pollution and the steps necessary to prevent it. The Act sets water quality standards, regulates point pollution sources, and allows the Environmental Protection Agency (EPA) to inspect storm sewer systems, factories, and construction sites to ensure that they’re using proper management systems.

More research has also helped us better understand sediment and its effects on water quality. Soil erodes a little more every time stormwater runs through it if proper erosion management strategies aren’t implemented. Forestry and agricultural practices can also disturb soil by loosening it when planting or harvesting, making it easier for soil to move with wind and weather into nearby bodies of water. Soil particles form sediment that lays in creeks, rivers, and streams, often creating cloudy, murky water that doesn’t receive enough sunlight to allow a flourishing habitat for the plants and animals that live there.

How is nonpoint source pollution different than point source pollution?

Photo by U.S. Government Accountability Office for Public Domain

You might hear polluted stormwater being referred to as nonpoint source pollution, also known as NSP, which is just another term referring to polluted stormwater runoff that damages bodies of water. NSP is a generalized term to cover water pollution that can come from a wide range of sources, meaning that it’s unlikely that we can pinpoint where or how the water became polluted.

When we can pinpoint a source, like factories and farms, then we refer to that pollution as point source pollution. Salt, construction site sediment, soil, agricultural waste, fertilizer, pesticides, and food grease from restaurants can all cause nonpoint source pollution. The EPA notes that nonpoint source pollution is a leading cause of water quality problems in the United States, while sediment remains the most common pollutant in many bodies of water.

Stormwater Prevention and Effective Management

Why is it important to manage stormwater properly?

Polluted stormwater runoff can affect virtually any location that doesn’t have an effective management system in place. Urban developments are especially at risk for water pollution caused by polluted stormwater runoff because there’s less ground to absorb water. However, rural areas are far from being in the clear; when more ground with loose soil is available, it’s easier for erosion to occur, leading to hazardous sediment collection in nearby bodies of water. When water sources become contaminated by polluted runoff, their natural ecosystems and our drinking water can suffer.

Wildlife and plants that exist in local water sources might not be able to survive if polluted water continuously makes its way into their home. Toxins from sediment, chemicals, and waste that stormwater runoff picks up along its path can quickly damage the ecosystem on which these living creatures depend for survival.

If your home or business uses water that comes from lakes, streams, or rivers rather than a well system, then your water supply might be affected by polluted stormwater runoff. Although the water that comes from these sources and into your home is treated before it reaches you, water treatment facilities must do more to treat polluted water than non-polluted water. For you, this likely means higher costs for bringing water to your home or business.

Stormwater runoff, when not managed properly, can also damage physical structures, like homes, roads, and schools. When water doesn’t have enough ground to absorb it, it will instead flow to its nearest sources, resulting in erosion and flooding.

How can stormwater be managed effectively in any area it poses a problem?

Stormwater runoff can be managed in various ways depending on the area and how runoff tends to take form in the area. Residential developments, for example, might warrant a different management system than an agricultural area. Construction sites also will require a much different form of management to prevent sediment from moving into runoff from storms.

One of the ways stormwater management professionals control runoff near and around homes is through adding hardscaping elements to yard and helpful landscaping touches. For example, a dry pond can hold stormwater runoff temporarily until it’s able to drain into the ground and surrounding plants. Stone walls can help guide water from runoff to prevent erosion and flooding. Or, strategically placed rain gardens can help absorb excess water from storms using native plants and shrubs. A professional landscaper can also suggest ways to keep your soil in place to control erosion during storms that leads to sediment buildup.

Paved areas can sometimes be made with porous materials to allow water to drain more effectively, and you might find storm drains nestled along sidewalks and roads to prevent flooding and erosion.

For farms and construction sites, the best stormwater management practices are often found in the prevention of their number one pollution source: Sediment. Agricultural practices have many erosion prevention techniques they can use, like strategic row arrangements to boost drainage and sediment basins that catch sediment from stormwater runoff. Construction sites – large or small – can implement helpful tactics to reduce pollution from sediment, like using only gravel driveways for construction vehicles to prevent mud tracking on roadways and adding drainage structures to the site before work begins.

How does a rain garden help reduce runoff?

Source: Bioretention system, or rain garden, in Portland, US by EmilyBlueGreen licensed under CC BY-SA 3.0

A rain garden can not only look beautiful in your yard, but it can also prevent stormwater from moving to bodies of water and polluting them. A rain garden usually sits on sloped areas where water from storms tends to travel downward into other areas of a lawn, into streets, or into nearby streams.

The rain garden’s primary purpose is to trap excess water that doesn’t go back into the ground. Then, the garden works to filter that water using the plants and soil contained in it. Most rain gardens contain plants you’d find in wetlands that have deep rooting systems to help absorb water. Think of it as a natural filtering process for stormwater that requires no chemicals to make the water safe again!

However, a rain garden is only designed to hold up to about an inch of water. After that water gets absorbed, extra stormwater will need a place to go. It’s crucial that your rain garden, therefore, also incorporates an erosion prevention strategy. You’ll often see rain gardens surrounded by mulch or compost to keep soil in place and allow for extra water absorption.

Are sewers and storm drains the same thing?

Storm drains and sewers are words often used interchangeably, but they are not the same thing. A storm drain usually is constructed as part of a curb to catch excess water runoff from roads to prevent flooding. The storm drain is part of a drainage system that carries that water, untreated, to a nearby source of water.

A sewer, on the other hand, carries sewage from homes and businesses that comes from kitchens, bathrooms, or washing machines. Some water in the sewage system might also come from rain and melting snow that drains through manhole covers. The sewage carried through a sewer system does get treated at a treatment facility to limit water pollution as much as possible.

What is a catch basin and how does it help manage stormwater?

Source: Storm sewer and catch basin by Imprezzive1 licensed for Public Domain

A catch basin is another name for a storm drain, or the opening near curbs that allows excess stormwater to drain before it floods roads and yards. Although a catch basin doesn’t help in preventing stormwater pollution, it does help to prevent roads, sidewalks, and structures from flooding by catching a significant amount of water during storms. Since a lot of stormwater will run into the catch basin instead of through yards and along roads, it is less likely to have as many contaminants in it as stormwater from areas without effective management systems. Catch basins can also reduce soil erosion by catching fast-moving water running down slopes and hills.

How does a stormwater runoff system store water to slow down runoff?

When we talk about a stormwater runoff system, we typically refer to ponds designed to hold water – permanently or temporarily – until it can be filtered. Storm drains are a necessary part of a storm management system, but they don’t store any runoff.

Stormwater ponds can be either dry or wet. A wet pond, as its name suggests, always holds water. It catches runoff from yards, roads, roofs, and other structures to keep it from running haphazardly in other areas and then filters the water over time. A dry pond usually resembles a grassy area you’d see in wetlands and is designed only to hold excess stormwater temporarily to prevent areas from flooding.

A rain garden can also catch some water from runoff as the plants within it absorb the water and the nutrients that they need from it, naturally filtering it before the rest goes into the ground.

Each of these elements works to store water in different ways until the ground is able to absorb it, essentially slowing down the path of stormwater that has nowhere to go but into nearby bodies of water.

My yard keeps flooding after storms. How do I stop stormwater runoff in my lawn?

There are a few ways you can control stormwater runoff on your lawn. A professional landscaper trained in stormwater management can help you find the best methods of management for the layout and slope of your yard.

A few ways stormwater can be managed in a yard to prevent flooding that can damage gardens, homes, and more, include:

  • Rain gardens, particularly on slopes where water rushes down into other parts of the yard, sidewalks, or roads
  • A drain system that catches water runoff and treats it underneath the ground
  • Hardscaping elements designed to strategically re-route the water and reduce erosion, like stone walls and permeable walkways
  • Dry or wet ponds to catch and hold water runoff
  • Use mulch or compost in your garden to help prevent soil erosion

How do I fix bad drainage in my yard or garden?

If your yard seems to be holding a lot of water after storms, then you may need the help of a professional to inspect the issue and determine a better way to drain your yard. In most cases, the combination of a draining system and landscaping and hardscaping elements, like mulching loose soil, planting a rain garden, and creating permeable surfaces, can help direct water into the ground or on a strategic path rather than allow it to pool on your lawn.

Your Contribution to Stormwater Management

Why do I see a stormwater management fee on my utility bill?

You might notice on your utility bill a stormwater fee. Not every municipality has one, but if yours does, you’ll see it listed on your statement like you would a sewer fee. The stormwater fee is in place by some municipalities to cover the cost of stormwater management as regulated by the EPA. The fee makes all residents in an area equally responsible for sharing the costs of implementing and maintaining effective stormwater management solutions.

How does this fee benefit me?

It can be alarming to see an extra charge on your bill, but the stormwater management fee is there for a useful purpose. When everyone shares in the cost of stormwater management, the result is an overall more effective system that keeps homes and businesses free from flooding and reduces the risk of water pollution.

Treating water after the fact is much more expensive than it is to put prevention strategies in place. Rather than spending extra money in taxes needed by your municipality to cover the costs of reversing the effects of polluted waters, like contaminated drinking waters and flooded roads, you can contribute toward stormwater management with a utility fee spread throughout the year.

How can I personally help to prevent stormwater pollution?

Source: Photo by U.S. Environmental Protection Agency for Public Domain

Preventing polluted stormwater runoff happens when practical measurements are put in place by towns and cities and their citizens. Stormwater management is something everyone – from state officials down to each individual citizen – should be knowledgeable about and work toward. Understanding what can pollute stormwater is the first step toward preventing pollution. Then, taking small – but crucial – steps to change some habits can have positive effects on stormwater management.

Some of the best ways you can prevent pollution in stormwater runoff are:

  • Landscaping and hardscaping your yard in a way that promotes stormwater management and reduces erosion
  • Limiting the use of fertilizers, pesticides, and herbicides
  • Taking proper measurements to dispose of hazardous chemicals and waste
  • Cleaning up pet waste
  • Sticking to an auto maintenance routine to prevent leaks of oil and fluids
  • Using household cleaners that are safe for the environment
  • Clean up grass clippings after mowing using a broom or bag instead of the hose
  • Sweeping dirt and debris off sidewalks and driveways
  • Dispose of cigarettes and chewing tobacco properly
  • Wash your car at a car wash or on a permeable surface, like gravel

It’s also important to notify your local officials if you notice that storm drains are clogged or not functioning properly, flooding, erosion, or anything else that seems out of place with stormwater management. The quicker the right people are notified, the faster a stormwater management issue can get corrected.

What can my neighborhood and town do to prevent stormwater pollution?

Proper stormwater management takes a commitment from everyone. You could have every effective management tool in place around your home to control polluted runoff, but if your neighbors don’t, then nearby waters will still suffer.

If you don’t believe your town is doing enough to prevent sediment buildup and pollution from stormwater, then you can always voice your concerns to your city officials. You might even write a petition asking for crucial changes to your town’s ordinances and get signatures from other citizens. Be sure to attend town meetings designed for citizens like you to ask questions and discuss issues.

How can I learn more about stormwater management and water pollution?

The number one tool you can have when it comes to stormwater management is education. The Environmental Protection Agency is an excellent resource to stay up to date with stormwater management and water quality control, but your local officials might also have information that’s highly relevant to your area. You can always check your local government website or visit department offices to learn more.

Many people go day-to-day without thinking much about their contribution to pollution. While some hazards, like car fluid leaks and pesticides, are obvious, other hazards, like soil erosion, might not be. The EPA lists several chemicals that pollute our waters, but it names sediment as the most common water pollutant. Unfortunately, this leading cause of water pollution is often overlooked by many yet is easy to spot when a stream becomes cloudy.

Understanding how improper stormwater management, flooding, chemicals, erosion, and the many other sources of pollution work together to negatively affect our bodies of water is the first step to raising water quality for all living creatures.