Gardening and Pesticides


Growing a healthy and beautiful garden goes hand in hand with using stormwater-friendly gardening practices.  


How Pesticides Impact Our Waterways

Your first reaction to dealing with pests or weeds in the garden may be to spray pesticides. However, many commonly used pesticides contain chemicals that can be lethal to marine life, birds, and other life forms, even in very small quantities. When you spray pesticides in your garden, water from rain or irrigation can wash those pesticides into local waterways or groundwater, causing water pollution. 

Small changes made around your home —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 in our local water quality. You can learn more about the use of pesticides in and around your home by also visiting the San Joaquin Valley Stormwater Quality Partnership [coming soon].

Learn more about pesticides and water quality here.

New link coming soon: Check back soon for a link to the San Joaquin Stormwater Quality Partnership website with more information about Pyrethroids and pesticide pollution prevention.

Pyrethroid Pesticides in Waterways

Although there are many different types of pesticides, one group of pesticides called pyrethroids is of particular concern because they are being found in our local waterways. Pyrethroid pesticides are primarily used for ants, cockroaches, and other insects. However, these specific pesticide components take a long time to break down into less harmful components once they enter 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:

·        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 a pesticide.

Luckily, there are ways to manage pests and protect our waterways at the same time. Read on to learn about integrated pest management (IPM).

Luckily, there are ways to manage pests and protect our waterways at the same time. Read on to learn about integrated pest management (IPM).


Integrated Pest Management

Integrated Pest Management (IPM) emphasizes using the least toxic pest management approaches. This includes tailoring treatment to the symptoms of the specific pest issue. Less than 3% of the insects you encounter in the garden are pests, and many are actually beneficial, so it’s important to identify and only treat the pest that’s causing the problem.


IPM utilizes a variety of approaches that effectively address the pest problems at their source. These include:

  • Mechanical/Physical: Try handpicking, barriers, traps or caulking holes to prevent infestations.
  • Biological: Find out what natural predators or beneficial insects can help you control your pest problem. For example, ladybugs and praying mantises are beneficial bugs that eat harmful pests.
  • Chemical: If you do use chemicals, identify the source of the pest problem and opt for the least toxic solution first. Check out Our Water Our World’s guide to less-toxic pest products.
  • Cultural: Look at environmental factors that affect the pest and its ability to thrive and create conditions that are unfavorable for the pest. Check out Our Water Our World’s guides to dealing with specific pests including ants, yellow jackets, aphids, and more.


Visit the University of California IPM website to learn more about IPM, including pest-specific advice. 


Purchasing Pesticides When You Need Them

“Point-of-purchase” or “point-of-sale” campaigns are focused efforts 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 Our Water – Our World (OWOW) is an example of an established point-of-purchase program that is implemented in retail stores that sell pest control products in northern California.

TAKE ACTION! 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. You can also click here to find a list of stores that participate in the OWOW program



Hiring A Landscaper or Pest Control Operator

Integrated Pest Management might sound complex, but you don’t have to do it alone! There are many professional gardeners and landscapers who specialize in eco-friendly pest management and landscaping practices. 


When looking for a pest management professional, look for these certifications:

  • EcoWise Certified professionals work to address the root cause of your pest issue. They use their knowledge of how pests live, feed, reproduce and move to effectively solve pest problems.
  • Green Shield Certified is an independent, non-profit certification program that promotes effective, prevention-based pest control that minimizes the use of pesticides.
  • Green Pro Certified is offered by the National Pest Management Association (NPMA) and recognizes pest management companies committed to providing customers with reduced risk, comprehensive and effective pest control services.
  • Additionally, check out this tip sheet for finding an eco-friendly pest management professional.


If you’re looking for broader landscaping services, check out these resources for finding environmentally friendly landscaping professionals: 

  • The ReScape Qualified Professionals Directory lists landscapers throughout California who conserve water and soil, reduce waste, and prevent pollution.
  • QWEL Pros  have been trained in efficient irrigation principles and sustainable landscaping practices to use water efficiently and prevent runoff.


Safe Use And Disposal Of Pesticides

Again, spraying pesticides should only be used as a last resort. If you do choose pesticides, follow these tips for minimizing pollution:

  • Select the least toxic product. Consider using bait stations or insecticidal soaps and oils.
  • Spot-apply pesticides or chemicals only to the area that needs treatment.
  • Time the application of chemicals such that they will have time to take effect and be absorbed before water carries them into storm drains. Do not use pesticides if rain is forecast within 24 hours.
  • Conserve water by only watering as much as your plants need and no more. This will help prevent landscape irrigation from running off your yard and into the streets and the storm drain system. 
  • Read the label of the pesticide you are thinking about purchasing to ensure that it is appropriate for the pest you are targeting. Follow all instructions on the label. Click here for what to look for on a pesticide label or here for common questions and answers about pesticide labels.
  • Properly dispose of leftover and unused pesticides. Residents can drop off leftover pesticides for free at San Joaquin County's Permanent Household Hazardous Waste Consolidation Facility at 7850 R.A. Bridgeford Street, Stockton, CA 95206.

Safely clean up spilled pesticides by absorbing it with sawdust or kitty litter. Sweep the absorbent material into a paper bag and dispose of it at the  local hazardous waste collection facility.