One of the most important things a well owner can do is regularly test their water supply to assure the health and safety of your family.

While the Environmental Protection Agency (EPA) regulates and monitors many drinking water contaminants, some pesticides are not regulated. Since many of us use pesticides to maintain our lawns and gardens, these substances can over time, leach into the groundwater.

Living near an area that is known to use pesticides such as farms, golf courses, orchards or even larger residential areas such as apartments, can make your well more susceptible to contamination.


Pesticides are chemicals that are used in commercial, agricultural and residential applications to control pests and/or weeds. There are a few different types of pesticides, including:

INSECTICIDES: used to control insect infestations

NEOMOTICIDES: used to control worms

FUNGICIDES: used to control mold and mildew issues

HERBICIDES: used to control weeds in residential or agricultural areas.


Since many contaminated wells go undetected, little is known about the long-term effects of trace amounts of pesticide in well water. However, the health risks from pesticides depend on a number of factors, including:

  • Amount of contaminants entering the water
  • Type of chemical
  • How long the homeowner has been consuming the contaminant
  • The person’s overall health before the contamination occurred

The EPA notes there are over 50,000 products containing over 600 pesticides and chemicals on the market.

The World Health Organiation (WHO) also looked at the health effects from pesticides and found:

  • Chronic exposure to highly hazardous pesticides can result in effects on skin, eyes, nervous system, cardiovascular system, gastrointestinal tract, liver, kidneys, reproductive system, endocrine system and blood.
  • Children are more vulnerable to the effects of pesticides because of their smaller size and hence greater exposure (on a milligram per kilogram body weight basis), different metabolism and still developing internal organs.
  • Although the evidence is less clear, some highly hazardous pesticides may also affect the immune system, and some obsolete pesticides may cause cancer, including childhood cancer.


Just because pesticides are used nearby does not mean your well water is in danger. Most modern wells have safeguards to protect against contaminants entering the water supply. A well more shallow than 50 feet in depth, older than 30 years, is damaged in any way, and wells surrounded by sandy soil can be more susceptible to contamination.

Pesticides can enter the water supply through several processes, but the most common is through leaching, or the downward movement (infiltration) of contaminants.

Inadequate well casing or annular seal may also allow surface water or contaminated groundwater to seep along the outside of the casing and enter your well.

To a certain extent the soil can filter out pesticides over time before they reach the groundwater, but sometimes they do not break down easily and may remain in soil for years of even decades.


You should always extra caution when using pesticides and other chemicals around your home, especially when you have a well. Here are a few tips on minimizing the risk of contaminating your well, or even your neighbor’s water supply.

CONSIDER THE WEATHER & IRRIGATION: Don’t use pesticides right before an expected rainfall or when irrigation systems will be used.

MEASURE CAREFULLY: Accurately calculate the correct amount needed for your yard.

CALIBRATE THE SPRAYING DEVICE: Make sure the desired amount is being applied

MIX AND POUR CAREFULLY: Avoid spilling access chemicals onto the ground when filling containers. If possible, mix and load on a permanent or portable containment pad to avoid saturating the soil with pesticide.

STORE SAFELY: Be sure to store the pesticides in a safe location, and also dispose of the leftovers properly.


You should always test your well annually as part of routine well owner maintenance. However, if there is a specific event that makes you question the quality of the water, get a specific test that will detect chemicals in the water.

If you do find your well is contaminated, or even suspect it is, you should immediately switch to bottled water and limit your time in the shower.

Contact your certified well professionals at Bedford Well Drilling to arrange further testing.

Remember, your well’s health is YOUR responsibility. Make sure you test your well annually and limit use of pesticides and other chemicals around your home to keep your water supply safe and clean.