Drinking water quality tells us if drinking water contains contaminants that may harm human health.
Some harmful contaminants can come from the natural environment, such as microbial contaminants in soil or metals in rocks. Other harmful contaminants come from human sources, such as fertilizers, pesticides, industrial and household wastes.

The Safe Drinking Water Act is the main federal law that protects drinking water quality in the United States. The U. S. Environmental Protection Agency (EPA) sets standards for drinking water quality to protect health, and the Colorado Safe Drinking Water Program enforces those standards. Private, individual household wells that serve fewer than 25 people are not regulated by the Safe Drinking Water Act. If you get your water from a private well you should have your water tested to make sure it is safe. You will need to pay for testing and maintaining your well.

We all use water every day. Not only do we drink water that comes out of the tap, but we also use it for cooking, cleaning and bathing. Contaminants in water can get into our bodies when we drink, eat or breathe in steam as we wash clothes or dishes or take a shower. Some contaminants can also be absorbed through our skin.

About 85% of Colorado residents get their drinking water from a community water system. Contamination of a single water system can expose many people to potentially harmful substances.

People exposed to contaminants in drinking water do not necessarily get sick. In fact, contaminants in water are usually not a health risk. But some contaminants can make people sick quickly. Others can become a health risk if people are exposed to them over many years.

The presence of contaminants in drinking water is not necessarily a health risk. It is reasonable to expect that all drinking water has small amounts of some contaminants in it. Even drinking water that has levels of contaminants above the drinking water standards set by the U.S. Environmental Protection Agency (EPA) does not necessarily mean that you will get sick. But some contaminants, such as bacteria or algae, can make us sick quickly. Others contaminants are generally only a health concern after years of exposure to levels above EPA health standards.

The health effects of any contaminant depend on:

• How much is in the water
• How a person is exposed to it (for example, through drinking or showering)
• How often and how long a person is exposed to the contaminated water
• If that person is particularly vulnerable (for example, children or someone who already has a health problem)

Some of the possible health effects of contaminated water include:

• Gastrointestinal illness: Nausea, vomiting and diarrhea can be caused by microorganisms in drinking water. Illness can begin soon after the person is exposed to the contaminated water
• Cancer: Some contaminants in drinking water, such as metals and solvents, can increase a person’s risk of getting cancer if the person is exposed to the contaminant over many years
• Other chronic conditions: Some contaminants can increase the risk of chronic conditions such as kidney disease, cardiovascular effects, or neurologic or developmental disorders

Several health effects have been associated with exposure to contaminants in drinking water in scientific studies. Some chemicals have been studied for many years and their effects on health are well understood. Others need more research to help us understand these connections better and see if these results are confirmed by additional studies.

Learn about health effects of arsenic ,disinfection byproducts ,nitrate.

To keep Colorado tap water safe to drink, sampling is required for public water systems. Compliance with safe drinking water regulations is enforced by the Colorado Safe Drinking Water Program. Water providers are required to inform the public if a problem is identified during sampling. When contaminants are discovered to be a public health risk, such as naturally occurring radionuclides, the Colorado Safe Drinking Water Program works with water treatment facilities to find a solution to the problem.

People who own private wells are responsible for sampling them to make sure the water is safe to drink. A variety of sampling kits are available from the Colorado Department of Public Health and Environment Laboratory Services Division.

Some people are more sensitive to environmental contaminants. These groups should be aware of ways to reduce the risk of exposure to contaminated water. Those most vulnerable groups are:

• Children
• Pregnant women
• Elderly people
• People with certain pre-existing health conditions
• People with poor nutrition

Protecting water sources, providing effective and reliable water treatment, maintaining water infrastructure and monitoring water quality are the main strategies used to make sure drinking water is safe. Drinking water treatment and contaminant standards are established and enforced by federal and state laws to protect people from contaminated drinking water.

There are things you can do to reduce your risk of being exposed to contaminated drinking water:

• Pay attention to information from your water provider. Certain contamination violations require that the water provider notify consumers in writing or even through television or radio messages if the health risk of the contamination is high.
• Read the Consumer Confidence Report that your water supplier sends you each year. It gives you information on your water source and if there were any violations of drinking water regulations during the year.
• If you get your drinking water from a private well, test your water regularly. A variety of test kits are available from the Colorado Department of Public Health and Environment Laboratory Services Division. You can learn more about drinking water from household wells in Colorado here.
• Help reduce water pollution by reducing the amount of pesticides and fertilizers you use and taking steps to keep pollutants away from storm drains.

EPA has more information on how you can help protect your drinking water.

Not necessarily. The Food and Drug Administration (FDA) sets bottled water standards based on the EPA’s standards for tap water. Both bottled water and tap water is safe to drink if it meets the standards.

You can learn more about the safety of bottled water from EPA. The Centers for Disease Control and Prevention (CDC) also has information about commercially bottled water and health.

While bottled water is very valuable in emergency situations, the cost per gallon of bottled water is much more expensive than tap water. Bottled water also raises environmental concerns due to the amount of energy and water used to produce, package, transport and dispose of plastic bottles. If you purchase bottled water please remember to discard the empty bottle in the nearest recycle bin.

How is data collected?
Public water systems are required to have their water tested periodically to make sure the water they provide meets health based standards. Water samples are sent to laboratories certified by EPA or the State. The results of these laboratory tests are then reported to the Colorado Safe Drinking Water Program. The Colorado Environmental Public Health Tracking program compiles drinking water quality statistics based on these reported test results. These statistics summarize the reported data.

How often is data collected?
How often a public water system tests its water depends on many things. Some of those variables are:

• How many people get water from that system
• The water sources the system uses
• Which contaminant is being tested for – different testing schedules are required for different types of contaminants.
• If the water system has failed to meet any drinking water regulation in the past

EPA’s website provides more information about how drinking water is tested. Your water provider sends you information about your tap water in a Consumer Confidence Report.