What contaminants can be present in well water?
Naturally occurring contaminants, like arsenic and radon, and contaminants introduced by people can be present in well water.
Contaminants introduced by people result from land use, stormwater overflow, and other events happening near your well. These may include:
- Pesticides
- Chemicals
- Harmful bacteria
Contaminants vary by location. All wells, despite a neighbor's lack of contaminants or varying well depth, should be routinely monitored to ensure your and your family's good health.
In Oregon, routine testing for the following is recommended:
If selling property in Oregon, these tests are required by law. Visit the Well User Resource Toolkit for more information about common well water contaminants in Oregon.
Can these contaminants make me and others sick?
The short answer to this question is yes. While it may depend on the toxicity of a chemical, its concentration, and the duration of exposure, well water contaminants can lead to short and or long term health effects. The Centers for Disease Control and Prevention (CDC) have identified the following to be the most common outbreaks in domestic well systems:
- Hepatitis A (liver disease usually spread by ingesting fecal matter)
- Giardia intestinalis (diarrheal disease caused by feces contamination)
- Campylobacter (infectious disease caused by bacteria)
- E. coli (bacteria caused disease)
- Shigella (infectious disease caused by a group of bacteria)
- Salmonella (infectious disease caused by a group of bacteria)
- Cryptosporidium (diarrheal disease caused by parasite)
- Arsenic and Nitrate poisoning (cancer and other symptoms)
- NEW! Harmful Algae Blooms English / Spanish (produce toxins, and when ingested can cause negative health effects)
While everyone in your household may not be affected, it is important to know that certain people can experience serious impacts. These groups include children, pregnant people, elderly community members, and individuals with compromised immune systems. To learn more about other contaminants and their health effects, visit Drinking Water Services' list of chemicals.
More information
Visit the Domestic Well Safety Program webpages for more information including details on: