NM EPHT Environmental Exposure Data: Drinking Water
People drink and use water every day. Therefore, the environmental health impacts of drinking water are important.
Drinking Water and Health
The majority of New Mexicans are provided high quality drinking water. About 90% of people in New Mexico get their water from a community water system. The U.S. Environmental Protection Agency (U.S. EPA) sets regulations for treating and monitoring drinking water delivered by community water systems. There are water quality standards and monitoring requirements for over 90 contaminants. About 10% of New Mexicans rely on smaller water supplies (mostly household wells) that are not regulated by the EPA or the state. Drinking water protection programs at the state and national levels play a critical role in ensuring high quality dinking water and protecting the public health.
On this Web site you will find information about the levels of five contaminants in drinking water: arsenic, nitrate, disinfection by-products, lead, and uranium. These contaminants were selected because they occur more frequently in drinking water al levels which may be of public health concern. The information focuses on community water supplies, as there are no data on water contaminants for private wells that are not regulated by the EPA or the state.
In New Mexico, the number of people served by a community water system varies from twenty-five to about half a million. Although community water systems in New Mexico provide among the highest quality drinking water in the world, some contaminants are present at low levels, and it is still possible that drinking water can become contaminated at higher levels.
Since people drink and use water every day, contaminants in drinking water may affect the health of many people. Since contamination in a single drinking water system can affect many people at once, drinking water quality is an important public health issue. People can be exposed to contaminants in drinking water not only by drinking the water, but also by eating foods prepared with the water, breathing water droplets or chemicals released from the water while showering or bathing, or by absorbing chemicals through their skin while bathing.
If a person is exposed to a high enough level of a contaminant, they become ill. Effects can be short-term (where people become sick immediately) and/or delayed (where people get sick after a long period of time). There are many types of health problems that can result from exposure to contaminants. The type and severity of the health problem depends on the specific contaminant, the level of the contaminant in the water and the person's individual susceptibility.
How can contaminants get into drinking water?
Drinking water can be contaminated by natural sources, like bedrock, or from man-made sources, like disinfection chemicals, agricultural run-off, or plumbing fixtures. Contamination can happen if there are new sources of contamination in the wells, reservoirs, lakes, or rivers that the water system uses, or if there are problems with the water treatment system.
This Web site includes information on the number of people drinking water by community water systems and contaminant levels over time, using data from state and EPA public drinking water programs.
Currently, we present summary statistics about community water systems within the state of New Mexico. This summary does not present data on whether or not individuals are actually being exposed to these contaminants or any health effects potentially resulting from drinking water contamination.
For more information on how contaminants may enter drinking water systems see the EPA Watershed Web site (http://www.epa.gov/owow/watershed/). For more information on drinking water exposure see the Centers for Disease Control and Prevention (CDC) Safe Water Web site (http://cfpub.epa.gov/safewater/sourcewater/) and the New Mexico Department of Health Environmental Health Epidemiology Bureau Web site (http://www.health.state.nm.us/eheb/). Or, call the Environmental Health Epidemiology Bureau Toll Free at 1-888-878-8992.
Who is at risk?
The risk of developing a specific disease depends on many factors such as:
- The specific contaminant, the level and potency of that contaminant.
- The way the contaminant enters the body (for example, drinking or showering).
- The person's individual susceptibility.
- Sensitive people, such as the elderly, children, pregnant women, and immune compromised, are more likely to suffer ill effects than the rest of the population.
The specific health risks associated with the contaminants presented on this Web site are discussed in detail on the following page, Drinking Water Contaminants.
Drinking Water Monitoring
Community water systems are required to provide drinking water that meets standards established under the Safe Drinking Water Act. The U.S. Environmental Protection Agency (EPA) sets drinking water standards for individual contaminants and groups of contaminants. Typically, water standards protect public health by limiting the levels of contaminants in drinking water. For public water systems, the federal government has established legally enforceable regulatory limits – National Primary Drinking Water Regulations (NPDWR) – for over 90 chemical and microbial contaminants in drinking water. These regulatory limits originate from the Safe Drinking Water Act and govern public water systems. New Mexico has adopted the federal standards. Users of private wells or other private water sources are solely responsible for monitoring and maintaining the quality of their water supply.
Public water suppliers are required to monitor the quality of the water they supply, and consumers must be notified if a primary standard is exceeded. There are two types of EPA standards:
- Primary drinking water standards (Maximum Contaminant Levels or MCL) are health-based and enforceable.
- Secondary drinking water standards (Secondary Maximum Contaminant Levels or SMCL) are based on aesthetics such as color, odor, and taste of the water. They are guidelines, not enforceable limits.
For more information on the Drinking Water Standards see the EPA Web site at http://www.epa.gov/safewater/standards.html.
Every year, community water suppliers send customers a "Consumer Confidence Report" that contains information about the quality of water. It includes information on where the water comes from, how it is treated, a list of the chemicals they test for, and the highest concentration of each chemical that they found in the past year. If you did not receive a "Consumer Confidence Report" you can obtain one by contacting your water supplier.
When a water system has a problem that might pose a risk to public health, they are required to notify their customers. The most common problems are contaminant levels that exceed health standards (water quality violation) or problems with the water treatment system (treatment technique violation). If it is a serious situation, they must notify the public within 24 hours; for less serious problems they must notify the public within 30 days. In some circumstances water systems must work with the state drinking water program to prevent a more serious problem, even if there has not been a violation.
For more information on public notifications of drinking water problems see http://www.epa.gov/safewater/publicnotification/pdfs/qrg_publicnotification.pdf
If your public 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 or the New Mexico Environment Department Drinking Water Bureau. See their Web site, http://www.nmenv.state.nm.us/dwb/, or call the Drinking Water Bureau Toll Free at 1-877-654-8720.
Drinking Water Contaminants: Arsenic (next page)