Pesticides and Stormwater | City of Davis, CA

The State of California has regulations in place to protect water quality in our waterways. These regulations focus on managing pesticide use to prevent harm to aquatic life in our streams and rivers. Such aquatic organisms include fish, reptiles, amphibians, crayfish, mussels, mollusks and crustaceans.

Any chemicals used in our yard and gardens can be washed off directly into streams and rivers. It is best to use less toxic pesticides or other means of controlling unwanted pests, rather than harmful pesticides.

More information about how pesticides are affecting water quality

flying-waterfowl

More information on how pesticides get into our streams and rivers

This webpage provides information about pesticides, less toxic alternatives to control pests and integrated pest management for residents and businesses. Small changes made around your home or business—something as simple as not spraying a pesticide on a windy day or addressing a pest issue without using pesticides—can make a big difference to our local water quality.

What are Pesticides?

Pesticides, which include insecticides and herbicides, are used to control unwanted bugs and plants (“pests”) such as ants, spiders, wasps, mice, rats, weeds or other unwanted organisms. Although efficient, even when used correctly, these chemicals can cause harm to human health or have negative consequences within the environment. It is important to consider less toxic or other alternatives and always follow label instructions when pesticide applications are needed.
pesticide-banner
Always read the label of the pesticide you are thinking about purchasing and select the pesticide carefully. Ensure that it is appropriate for the pest and determine where you will use it.

Learn more about how to read a pesticide label

EPA website: Pesticide Labeling Q & A

In California, pesticides are regulated by the Department of Pesticide Regulation (DPR) as well as by the United States Environmental Protection Agency (USEPA). To learn more about why pesticides can be harmful and how they are regulated, visit the following websites:

Pyrethroid Pesticides in Waterways

Although there are many different types of pesticides, one group of pesticides called pyrethroids are of particular concern because they are found in our local waterways. Pyrethroid pesticides are primarily used for ants, cockroaches and other insects. These pesticides take a long time to break down into less harmful components once they are in the environment, which means that they can cause unintended harm to many other types of beneficial insects (e.g., bees, ladybugs) and aquatic life.

Products that contain pyrethroids typically have active ingredients that end with the letters “-thrin.” When reading the pesticide label, look to see if any of the active ingredients include the following pyrethroids:

Permethrin
Bifenthrin
Cyfluthrin
Beta-cyfluthrin
Cypermethrin
Deltamethrin
Lambda-cyhalothrin
Tralomethrin
Esfenvalerate (an exception to the “-thrin” rule)

If a pyrethroid is an active ingredient, consider other ways that you might address the pest, such as other less toxic pesticides or controls that do not require the use of that pesticide.

Learn more about Pesticides and Water Quality

Less toxic pesticide management

Choosing a Less-Toxic Pesticide

There are many different ways to choose the "least toxic" way to manage pests, and the abundance of choices can be confusing. To make this simpler, the City of Davis partners with Our Water – Our World to educate and raise awareness among both retailers and consumers so that they can make informed decisions about what types of products are available for sale (retailers) and what products are most effective, least harmful, and ultimately purchased (consumers). Point-of-purchase displays often include materials such as shelf edging or tags and display stands with fact sheets, banners, and other educational materials.

Next time you visit your local gardening and home supply retailer, look for displays and educational materials about pesticides and which controls are best for each type of pest that you may encounter. Find stores near you that participate in the OWOW program.

Pesticides and Gardening

Unwanted insects in your lawn, garden or home can be a source of frustration and may damage the plants that you are trying to grow and maintain. Some pests may also transmit disease. In order to effectively prevent or remove these pests, it is important to understand what is attracting them, how they are entering the home or garden and what control is best for that specific pest. Approaching pests in this manner will save money, have a longer-lasting effect on the pest and protect the environment.

The next time you need to address a pest in your home or garden, follow the steps below.

1. Identify if the Bug is Good or Bad

Check if the bug you are seeing is a beneficial insect that eats the “bad” bugs and pollinates your plants.

The 10 Most Wanted Bugs in Your Garden
How to Identify Common Beneficial Insects

2. Identify What Controls are Best for Your Pest

Our Water Our World and the UC Integrated Pest Management Program have detailed information that can help you determine the best method to control your pest.

English: Ants | En Español: Hormigas
English: Aphids | En Español: Áfidos o pulgones
English: Bed Bugs | En Español: Chinches
English: Cockroaches | En Español: Cucarachas
English: Fleas | En Español: Pulgas
English: Moles, Voles, Gophers | En Español: Tuzas
English: Mosquitoes | En Español: Mosquitos
English: Rats and Mice | En Español: Ratas y Ratones
English: Snails and Slugs | En Español: Caracoles y babosas
English: Spiders | En Español: Arañas
English: Yellow Jackets | En Español: Avispas chaqueta amarilla

3. Consider Non or Less Toxic Alternatives

First, try to control pests with less toxic methods, such as traps, mulch, insecticidal soap or beneficial insects like ladybugs. To learn more about less toxic pest management methods and products, visit the OWOW partnership or University of California.

4. If You Must Use Pesticides – Follow These Best Practices

Read labels and apply pesticides using recommended amounts and application methods.
Use the least amount of chemical needed. Remember, more is not always better.
Avoid application when it is windy or before it rains.
Don’t overwater the area immediately after pesticide application. Excess water will carry the chemicals straight to the storm drain system and then to the local streams and rivers.
Take care not to spill the product, and don’t rinse spills into the street. If a spill occurs, absorb it with sawdust or kitty litter, sweep the absorbent material into a paper bag, and take absorbent material to your local hazardous waste collection facility.

UC Davis IPM website: Pesticides: Safe and Effective Use in the Home and Landscape

Disposing of Pesticides

Hiring Pest Control and Landscape Professionals

When dealing with unwanted pests around your home or business, you may want to hire a pest control service to take care of the problem for you. Pest control professionals have access to different products, specialized training and other equipment that may be needed in order to manage a serious infestation or problem.

Pest management professionals can learn more about integrated pest management approaches and available training by visiting the UC IPM Program for structural pest management or landscape pest management.

spraying By following these steps, you can support pest control companies that understand and implement integrated pest management and less toxic approaches.

Do some research about the pest you have and how it can be controlled.
Ensure the pest control operator has a license issued by the California State Structural Pest Control Board and any other registrations, certifications, or insurance required. To verify the license for a pest control operator, visit the Department for Consumer Affairs.
Hire a pest control operator who is certified as using integrated pest management practices, applies effective non-chemical strategies first and knows how to effectively manage pests.

Our Water Our World: Hiring a Pest Control Company
UC Davis IPM: Hiring a Pest Control Company

Several certification groups can also be helpful in finding a pest control company:

Eco Wise Certified
Green Shield Certified
Green Pro Certified

Landscape Design and Irrigation Management to Prevent Pesticide Runoff

Proper design and management of the landscaping around our homes and businesses can help prevent pesticide runoff from these areas into local waterbodies. Here’s some resources that may help:

gravel CA Dept of Water Resources: Water Efficient Landscaping
SaveOurWater: Conserve Water Rain or Shine
UC Seasonal Landscape IPM Checklist

Slow the flow by following the University of California’s Statewide Integrated Pest Management Program recommendations for pesticide-smart landscape design:

Help water soak into the ground.
- Use stones, pavers, gravel, mulch or other materials that allow water to soak into the ground in areas where you don’t have plants.
- Aerate your soil and use organic material, like compost, and consider using perforated drainage lines to reduce areas of water pooling in your landscaping.
Create landscape features to collect runoff water.
- Consider using trees, rain gardens, terrace walls, rain barrels or swales (long, shallow, grassy depressions) to hold water within the landscaped area and allow it to soak into the ground rather than draining directly to our surface waterbodies.
- Consider using river-friendly gardening approaches such as selecting appropriate plants, minimizing the use of chemical pesticides and creating "hydrozones" by grouping plants according to water needs. Learn more about how to make your yard river-friendly on the Lodi Watershed Friendly Landscaping website or by following these River-Friendly Landscape Guidelines.
Install and properly operate irrigation systems and equipment.
- Make sure your irrigation equipment is working properly by regularly inspecting it and consider installing a “smart” irrigation controller to reduce overwatering.

Helpful Links

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