Stormwater - Top Tips

Washington State Department of Ecology

Stormwater Top Pollution Prevention Tips

Operational Best Management Practices (BMPs)

Train all employees in the importance of pollution prevention, spill response procedures, and environmentally acceptable material handling.
Maintain a clean and orderly work environment.
Store materials in proper, appropriately labeled containers.
Identify and label all chemical substances.
Keep materials to be recycled separate from other waste.
All stormwater management devices should be inspected regularly and maintained as necessary.
Stencil catchbasins with a "Dump No Waste" message.

Use of Oil/Water Separators

These BMPs must be regularly inspected and undergo preventative maintenance in order to work well.
Direct vehicle or equipment washwater away from separators. Soapy washwater can flush oil and grease out of the separator and into surface or ground water.
Never use the presence of an oil/water separator used as a rationale for poor housekeeping. Vehicles should be drained of fluids before they are stored long-term, and should be regularly checked for leaks. Fluids drained from vehicles should be separated and recycled whenever possible.

High Use Vehicle Areas

Stencil all stormdrains with a "Dump No Waste" message.
Install oil removal systems such as API or CP-type separators, catchbasin filters, media filters, or other BMPs. In this case, catchbasin filters (many kinds are available) are probably better for use than are oil/water separators.
Standard catchbasins have the ability to settle large particles out of stormwater but they cannot catch the smaller particles that carry the most pollutants. They should not be considered a BMP. You can add filters of many kinds easily and cheaply to catchbasins to make them more effective. Many of these filters also have the ability to trap oils discharged to catchbasins.

Vehicle and Equipment Washing

Where possible, vehicle and equipment washing should be done indoors, where contaminated washwater can be discharged to the sanitary sewer.

Landscaped Areas

Landscaped areas have the potential to contribute nutrients, pesticides and fecal coliform bacteria (through animal waste, fertilizer, and compost) to stormwater runoff. They can also collect litter, and poorly maintained areas may impede stormwater drainage.

On the plus side, landscaped areas can be used to spread out and reduce the volume and velocity of runoff, remove sediment, and function as multi-use areas (for example, temporary stormwater detention in recreational fields).

Use Integrated Pest Management (IPM) to determine when a pest infestation is serious enough to be dealt with by chemical or other means. Use the least toxic control method available to accomplish the task.
Only use well-rotted manure as fertilizer.
Keep stockpiles of bark or topsoil covered until use. Where possible, avoid the use of slick plastic fabrics to mulch around plants. Bark spread on this material tends to float off during storms and block drains and curb cuts.

Erosion and Sediment Control

Inspect all landscaped areas and stormwater control BMPs to make sure there is no erosion.
Check to see that discharge points are properly vegetated or riprapped to prevent erosion from undercutting these areas.
Clear away any unwanted vegetation and sediment accumulations on a regular basis to make sure that flow isn’t impeded. Backed-up runoff will always find an outlet, however it may not be the one that was designed for it!

Source Control

Source control BMPs are the only BMPs which are 100% effective. If a pollutant never gets into runoff, then it never has to be taken out. As a general rule, take the following steps:

Alter the pollutant source activity to prevent release.
Enclose, cover, or contain activities.
Provide containment for control of leaks and spills.
Discharge contaminated stormwater to a sanitary sewer or process water treatment.

Related information

Stormwater is a page from Water Quality that discusses prevention of polluted runoff.

Stormwater Management and Design Manuals offer guidance.