Drinking Water Regulations

The primary drinking water regulations are a set of legally enforceable standards established by the United States Environmental Protection Agency (EPA) under the Safe Drinking Water Act (SDWA). These regulations set maximum contaminant levels (MCLs) for various contaminants in public water systems, including microorganisms, disinfectants, disinfection byproducts, inorganic and organic chemicals, and radionuclides. The primary drinking water regulations aim to ensure that drinking water is safe for human consumption.

The primary drinking water regulations include the following:

1. Maximum Contaminant Level (MCL) Regulations: These regulations establish the maximum allowable level of various contaminants in drinking water, such as bacteria, viruses, and other microorganisms, disinfectants like chlorine and chloramine, disinfection byproducts like trihalomethanes, and organic and inorganic chemicals like lead, arsenic, and mercury.

2. Treatment Technique (TT) Regulations: These regulations require water systems to use specific treatment techniques to remove contaminants that are not subject to MCLs.

3. National Primary Drinking Water Regulations (NPDWRs): These regulations set the standards for drinking water quality and establish the MCLs and TT requirements for contaminants that may adversely affect public health including microorganisms, disinfectants, disinfection byproducts, inorganic and organic chemicals, and radionuclides. 

4. Surface Water Treatment Rule (SWTR): This rule requires public water systems that use surface water sources to disinfect their water supplies and control the levels of microbial contaminants.

5. Total Coliform Rule (TCR): This rule requires public water systems to monitor for the presence of total coliform bacteria in their water supplies, which can indicate the potential presence of harmful microorganisms.

6. Lead and Copper Rule (LCR): This rule requires public water systems to take actions to reduce lead and copper levels in drinking water, such as corrosion control and monitoring.

Overall, the primary drinking water regulations are intended to protect public health by ensuring that drinking water is safe and free from harmful contaminants.

To learn more about primary drinking water regulations, visit the EPA Primary Drinking Water Regulations Site.

In addition to the primary drinking water regulations, the United States Environmental Protection Agency (EPA) has also established secondary drinking water regulations under the Safe Drinking Water Act (SDWA). Unlike the primary regulations, the secondary regulations are not legally enforceable standards but instead provide guidance on non-health-related issues that can affect the taste, odor, and appearance of drinking water.

The secondary drinking water regulations address aesthetic factors, such as taste, odor, and color, and do not directly relate to the health effects of contaminants. These regulations establish recommended levels for contaminants that may affect the aesthetic quality of drinking water, including:

1. Aluminum: The recommended level for aluminum is 0.05 to 0.2 milligrams per liter (mg/L), as concentrations above this range can cause water to have a metallic taste.

2. Chloride: The recommended level for chloride is 250 mg/L, as higher concentrations can affect the taste of water and may cause corrosion in plumbing systems.

3. Color: The recommended level for color is 15 color units, as water with a high color value can have an unpleasant appearance and may indicate the presence of organic matter.

4. Copper: The recommended level for copper is 1.3 mg/L, as higher concentrations can cause blue-green stains on plumbing fixtures.

5. Iron: The recommended level for iron is 0.3 mg/L, as higher concentrations can cause water to have a metallic taste and can stain plumbing fixtures.

6. Manganese: The recommended level for manganese is 0.05 mg/L, as higher concentrations can cause water to have a bitter taste and can stain plumbing fixtures.

7. Sulfate: The recommended level for sulfate is 250 mg/L, as higher concentrations can cause water to have a laxative effect and can cause corrosion in plumbing systems.

Overall, the secondary drinking water regulations are intended to address non-health-related factors that can affect the aesthetic quality of drinking water. While these regulations are not legally enforceable, they provide guidance for water system operators to maintain the quality and appearance of drinking water.

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that have been widely used in various industrial and consumer products, such as non-stick cookware, stain-resistant fabrics, firefighting foams, and food packaging. PFAS are persistent and can accumulate in the environment, including in water sources, and have been detected in drinking water supplies across the United States.

Exposure to PFAS has been linked to adverse health effects, including developmental delays, decreased fertility, liver damage, immune system dysfunction, and some types of cancer. In response to these concerns, the United States Environmental Protection Agency (EPA) has established a health advisory level of 70 parts per trillion (ppt) for two types of PFAS chemicals, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), in drinking water.

Although the health advisory level is not a legally enforceable standard, the EPA recommends that public water systems take steps to reduce PFAS levels in drinking water supplies. Some states have also established their own regulations and guidance on PFAS in drinking water, and some have established lower standards than the EPA's advisory level.

Treatment technologies, such as granular activated carbon (GAC) and reverse osmosis, have been shown to be effective in removing PFAS from drinking water. The EPA recommends that water systems test for PFAS and take appropriate actions if levels are found to be above the health advisory level. The agency is also working to establish regulatory standards for PFAS in drinking water, which would establish legally enforceable limits for these contaminants.

Emerging contaminants are a group of chemicals or substances that are not currently regulated under existing federal or state drinking water regulations but may pose a potential risk to human health or the environment. Some of these emerging contaminants have been detected in drinking water supplies in various parts of the United States, raising concerns about their potential health effects.

Examples of emerging contaminants in drinking water include:

1. Pharmaceuticals and personal care products (PPCPs): These are chemicals found in medications, cosmetics, and other personal care products that are often not completely metabolized by the human body and can enter the environment through wastewater treatment plants. Examples of PPCPs include birth control pills, antibiotics, and fragrances.

2. Endocrine-disrupting chemicals (EDCs): These are chemicals that can interfere with the normal function of hormones in the body and may be associated with developmental, reproductive, and other health problems. Examples of EDCs include bisphenol A (BPA), phthalates, and nonylphenol.

3. Microplastics: These are small pieces of plastic that can come from a variety of sources, such as plastic bags, bottles, and microbeads in personal care products. Microplastics have been found in drinking water supplies around the world, but their potential health effects are not yet fully understood.

4. Cyanotoxins: These are toxins produced by certain types of algae that can form in surface water sources during warm weather conditions. Exposure to cyanotoxins can cause skin irritation, respiratory problems, and other health effects.

The presence of emerging contaminants in drinking water is a growing concern, and the United States Environmental Protection Agency (EPA) is actively researching and monitoring these substances to better understand their potential risks and establish appropriate regulatory standards.

The Unregulated Contaminant Monitoring Rule (UCMR) is a program established by the United States Environmental Protection Agency (EPA) to monitor the presence of unregulated contaminants in drinking water supplies. Unregulated contaminants are chemicals or substances that are not currently regulated under existing federal or state drinking water regulations, but may pose a potential risk to human health.

The UCMR requires public water systems to conduct monitoring for a specific list of unregulated contaminants every five years. The list of contaminants is updated regularly based on new information and emerging concerns. The UCMR program helps the EPA gather data on the occurrence of these contaminants in drinking water supplies, as well as their potential health effects, which can be used to inform future regulatory decisions.

The UCMR program has two monitoring cycles. The first cycle, UCMR1, was conducted from 2001-2005 and included monitoring for 25 unregulated contaminants. The second cycle, UCMR2, was conducted from 2008-2012 and included monitoring for 30 unregulated contaminants. The current cycle, UCMR3, was conducted from 2013-2015 and includes monitoring for 30 contaminants.

The UCMR program is an important tool for identifying potential risks to public health from unregulated contaminants in drinking water. The EPA uses the data collected through the UCMR program to determine if further regulatory action is necessary to protect public health.

Much of the UCMR data exists in public record. If you are curious about what's in your water, call your water provider or visit our resource page here.