Drinking water contaminants may be present in both regulated (all community water systems) and unregulated (some small water systems, private wells, streams and lakes) sources of drinking water. Strategies to avoid the accumulation of contaminants in drinking water include:
- Protecting water sources by limiting use and properly disposing of hazardous materials (such as pesticides or fertilizers, motor oil, leftover paints or paint cans, mothballs, flea collars, household cleaners, and medicines), and by volunteering to clean up a local beach, stream, or wetland
- Providing effective and reliable water treatment
- Monitoring drinking water quality & notifying consumers when levels of contaminants exceed regulatory limits, or maximum contaminant levels (MCL).
Regulated Drinking Water
Federal laws and regulations are in place at the state level to implement these strategies for community water systems (CWS). The majority of CWS in the US meet all health-based water quality standards. As a result, the risk of developing a disease from drinking water supplied by CWS is low. However, there are still areas where existing contaminant levels may pose some risks to the population.
When a CWS has a problem that might pose a risk to public health, the water system's management is required to notify their customers. If your water system has notified you that there has been a problem, you should carefully follow the advice given by the water system and the local public health officials. If you think there is a problem with your drinking water, you should call your water provider. For help in locating these agencies or for information on drinking water in general, call the US Environmental Protection Agency's (EPA) Safe Drinking Water Hotline: (800) 426-4791.
Unregulated Drinking Water
Small drinking water supplies not covered by the Safe Drinking Water Act (SDWA) and private domestic wells, which are virtually unregulated, may be more likely to have harmful contaminants. If you have your own private water supply, you are responsible for maintaining and testing it. If you are camping or hiking, it is important to bring potable water and/or water treatment equipment. Surface water sources such as streams and lakes are more likely to be contaminated with bacteria and viruses like Cryptosporidium, Giardia, and norovirus, as well as chemicals like nitrate.