Stormwater Management Frequently Asked Questions

Download Stormwater Management FAQ’s

Click Here to view an informational brochure produced by the EPA entitled After the Storm, A Citizen’s Guide to Understanding Stormwater.

What is Stormwater runoff?

Stormwater is the non-infiltrated runoff water that accumulates and flows through gutters, ditches, and storm drains during runoff producing events. Typically, the more rainfall we get the less likely that the rainwater will be absorbed into the soils resulting in more stormwater reaching our storm drains, ditches, streams, lakes and reservoirs.

Where are storm drains?

For the most part, storm drains are located within the limits of the streets. Water typically flows across the land onto the road and gutters and into stormwater inlets which are part of the storm sewer system. In the more rural areas, stormwater is conveyed along roadside ditches.

What is the difference between a storm sewer and a sanitary sewer?

The storm sewer system takes stormwater runoff from parking lots, roads, and ditches and transports it into creeks, rivers, and lakes. Whatever goes into the stormwater drainage system is what goes into our waterways, untreated. Sanitary sewers take household water and waste from toilets, sinks and showers, and transport it to a wastewater treatment facility. There, the water is treated and then discharged back into a creek, stream, river, or lake.

Does this stormwater get treated at the wastewater plant?

No, stormwater collected in the storm sewer system drains untreated into the nearest natural water source. The water that sheds from your roof, lawn, driveway, and the streets carries the fertilizers from your yard or the oil and debris from your driveway and discharges these pollutants into the surrounding streams, rivers, or lakes.

What kind of pollution is in stormwater runoff?

The pollution depends on where and what the rainfall runoff is draining from. Nearly all runoff contains silt and soil as a result of erosion. Runoff from agricultural lands and our lawns often contain fertilizer and herbicides. Runoff from streets and highways may contain oil and grease plus heavy metals such as lead from gasoline exhaust emissions and selenium from tires.

What about Bacteria?

Another pollutant which gets into the stormwater is bacteria. Bacteria originates from illicit sanitary sewer connections or overflows and pet or wild animal waste. The City has a program to eliminate illicit sanitary sewer connections and overflows. Picking up pet waste and properly disposing of it also will help reduce bacteria in stormwater.

Is blowing lawn clippings down the storm drain or placing them in the wetland area behind my house a bad thing? Don’t they work like mulch or compost?

Yard waste is harmful to our waterways because it contains natural fertilizers like Nitrogen and Phosphorous, which can create algal blooms down-stream. Fish kills are a common result of excessive fertilizers and organic matter in our waterways. In addition, yard waste can clog up the storm drainage system, increasing an area’s chance of flooding and water damage to properties.

Your grass clippings are useful to your lawn if used properly. Using a mulching mower, mowing often, and mowing your grass to about 3.5” will promote a healthy lawn. More importantly, the taller grass will help to keep the clippings in place during decomposition helping to prevent it from washing into the storm drains and natural watercourses during rain events.

What is a BMP?

BMP is short for “best management practice.” A Best Management Practice or BMP is any schedule of activities, physical structure or facility, maintenance procedure, or other management activity intended to prevent or reduce the discharge of pollutants to our waterways. BMP’s can be either an activity, such as limiting the use of fertilizers, or a structure, such as a detention pond. BMP’s are used to counteract the impacts of development on our natural environment.

What can I do to help prevent stormwater pollution?

If you own a car, maintain it so it does not leak oil or other fluids. Be sure to wash it on the grass or at a car wash so the dirt and soap does not flow down the driveway and into the nearest storm drain.

If you own a yard, do not over fertilize your grass. Never apply fertilizers or pesticides before a heavy rain. If fertilizer falls onto driveways or sidewalks, sweep it up instead of hosing it away. Mulch leaves and grass clippings, do not sweep them into the storm drain. Turn your gutter downspouts away from hard surfaces, seed bare spots in your yard to avoid erosion and consider building a rain garden in low-lying areas of your lawn.

If you have a septic system, maintain it properly by having it pumped every three to five years. If it is an older system, be sure it can still handle the volume placed on it today. Never put chemicals down septic systems, they can harm the system and seep into the groundwater.

Pet owners should pick up after their pets and dispose of pet waste in the garbage. Keep lawn and household chemicals tightly sealed and in a place where rain cannot reach them. Dispose of old or unwanted chemicals at household hazardous waste collection sites or events.

Visit our pollution prevent page for more helpful tips, and remember, only rain down the storm drain!