Water Decontamination Frequently Asked Questions for Customers

These Frequently Asked Questions (FAQs) are intended to address commonly asked questions about water contamination from public water system (PWS) customers and to provide ways to stay informed throughout the remediation process of a water contamination incident.

Where does my drinking water comes from?

I buy my water from a water company – Your water will typically come from either surface water or groundwater. Your water utility prepares an annual report describing the source and quality of your drinking water, called a Consumer Confidence Report (CCR). You can find your water utility’s CCR by checking the utility’s website, calling the water utility and asking for an electronic or hard copy, or by using EPA’s Find Your Local CCR. EPA also provides a guide on Understanding Your Water Quality Report.

I have my own personal well or spring – Wells are not regulated by EPA. This FAQ document is focused on public water system customers. To find more information about the source of well water and associated regulations, contact your local health department or state department of environmental quality. Resources exist for homeowners regarding well water protection, such as EPA’s Protect your Home’s Water, EPA’s Private Drinking Water Wells, and CDC’s Disinfecting Wells After a Disaster.

What can I do to protect my drinking water?

EPA provides information on steps that can be taken by communities, citizen groups, and individuals to Help Protect Source Water from contamination. This includes staying educated about your source water and learning how to use and dispose of harmful materials properly.

You can also learn more about Pollution Prevention, which aims to reduce, eliminate, or prevent pollution at its source before it is created, thereby decreasing impacts to public health and the environment. EPA gives tips on What You Can Do about Pollution Prevention.

What is a contaminant?

The Safe Drinking Water Act broadly and indirectly defines a “contaminant” as anything other than water molecules. The presence of a contaminant does not necessarily indicate that the water poses a health risk. EPA sets regulations on both naturally-occuring and man-made contaminants that have been shown to pose a risk to human health and the environment.

Drinking water contaminants can include bacteria, pesticides, industrial chemicals, and chemicals found in gasoline. EPA provides general information on the Types of Drinking Water Contaminants and How EPA Regulates Drinking Water Contaminants.

How do contaminants get in drinking water?

EPA gives an overview of factors that can impact water quality, including point and nonpoint source pollution and water availability. Point source pollution refers to pollution that can be linked to a single location, such as an industrial plant, whereas nonpoint source pollution cannot be pinpointed to a specific location, such as stormwater runoff. Water availability refers to volume of water accessible for use and can be impacted by droughts, for example.

Water pollution can also occur through a water contamination incident, which involves an incident that may have significant and immediate impacts on water quality. Water contamination incidents come in many forms, ranging from extreme weather events to large accidental spills or intentional acts.

How will I know if my water is safe to drink?

Under the Safe Drinking Water Act’s Public Notification Rule (PN), drinking water utilities are required to notify their customers if there is a problem with their drinking water. These notices alert consumers if there is risk to public health. During a water contamination incident, your water company will announce if there are any precautionary actions you should take, if there are restrictions to water use, and advise when the water is safe to drink. Call your water company if you think your tap water is contaminated and your water system has not yet issued a drinking water advisory. If you would like to have your drinking water tested, EPA provides resources to find a laboratory certified by your state or territory for drinking water.

To find general source water quality information, you can use EPA’s How’s My Waterway tool, which was designed to provide the public with an easily accessible and understandable picture of water quality at a community, state, or national scale.

Are there different types of drinking water advisories?

Yes, there are different types of water advisories depending on the severity and scope of contamination that warn the public of short-term water quality issues with their drinking water. Different types of contaminants have varying properties that are used to determine what type of water advisory is necessary. There are three broad types of water advisories:  Boil Water Advisory, Do Not Drink Water Advisory, and Do Not Use Water Advisory.

• Boil Water – Use bottled water or drinking water only after letting the water boil for one minute (at elevations above 6,500 feet, boil for 3 minutes) and then letting it cool. The advisory may also include information on food and drink preparation, as well as hygiene practices.
• Do Not Drink Water – Use bottled water only. You should not use your drinking water in beverages or for cooking, and there may also be restrictions for bathing and dishwashing.
• Do Not Use Water – Use bottled water only. You should not use your drinking water for any reason.

Always follow the directions set by your water system during a water advisory. If you have questions about something that is not listed in the advisory, contact your water company and refer to CDC guidance on household activities you should and should not do during a Drinking Water Advisory. To learn more about bottled water, read EPA’s Bottled Water Fact Sheet.

When an advisory is lifted, can I immediately drink the water?

If the incident affected your drinking water system, the contaminant could enter your home plumbing if you have used any faucets or appliances during the period of contamination. You may be advised to flush water connected to your service line before using the water normally.

What is flushing, and how do I know if I need to flush the pipes inside my home?

Flushing involves opening valves and faucets and allowing water to flow to remove any residual standing water from interior pipes and/or outlets. Flushing times vary by the type of plumbing and outlets being cleared.

Your water system should tell you if, how, and to what extent you need to clean your water service line and any appliances that are connected to your water line. You may be instructed to flush water from your faucets and appliances after a drinking water advisory has been lifted and before returning to normal water usage. This helps clean the pipes in your building and brings more clean water into the water mains in your area.