Protecting Public Health and the Environment.

Frequently Asked Questions about Drinking Water in Idaho

About My Drinking Water

Where does my drinking water come from?

Approximately 1,946 public drinking water systems serve more than 1,364,608 people in Idaho. Approximately 95% of the state's drinking water comes from ground water. The remaining 5% is supplied through surface water such as streams, rivers, reservoirs, and springs.

How do I know if my drinking water is safe?

Overall, Idaho's drinking water is quite safe, although local contamination has been discovered in some of the state's ground water resources. The best source of specific information about your drinking water is your water supplier. Each year, community water systems in Idaho are required to prepare annual Consumer Confidence Reports (CCRs) for their customers informing them where their drinking water comes from and what is in it. (A community water system is a public water system that serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents, such as a municipality, subdivision, mobile home park, apartment complex, or nursing home.) Contact your water supplier to get a copy.

DEQ posts real-time water quality data for all public water systems on the PWS Switchboard. Go to the “Sample Results” button in the “Tool/Data” column, select the public water system, and select sample results of interest. A summary of sample results and overall water quality at each system is also included in the CCR referenced above.

For additional information, contact EPA's Safe Drinking Water Hotline at 1-800-426-4791 or to find out about drinking water and ground water programs authorized under the Safe Drinking Water Act.

How will I know if my water is not safe to drink?

Public notification is a state and federal requirement intended to ensure that consumers will always know if there is a problem with their drinking water. Public water systems must notify the people who drink their water if the level of a contaminant in the water exceeds Idaho's drinking water regulations, if a waterborne disease outbreak or any other situation occurs that may pose a risk to public health, and if the water system fails to test its water as required. These notices immediately alert consumers (within 24 hours or sooner) if there is a serious problem with their drinking water (e.g., a boil water emergency). For less serious problems (e.g., a missed water sampling test), water suppliers must notify consumers in a timely manner—depending on the violation—anywhere from 3 to 12 months.

The notice will describe any precautions you need to take, such as using only bottled water or boiling your water. If a public notice is published and distributed regarding your drinking water, carefully read and follow the instructions.

What does MCL refer to?

In general terms, maximum contaminant level (MCL) is the maximum amount of a contaminant that is allowed in drinking water to ensure that the water is safe for people to drink. Water meeting the MCL standards is considered safe to drink, although some people, such as those with severely compromised immune systems, children, and the elderly, may have special needs.

What are the two general methods for disinfecting small quantities of water?

Emergency or short-term treatment of drinking water may be required when the water supply to your home is interrupted due to natural disasters, accidents, or other causes. Small quantities of water can be effectively disinfected through two general methods.

  1. Boiling: Vigorously boil water for 1 minute. The flat taste of boiled water can be improved by pouring it back and forth from one container to another (called aeration), by allowing it to stand for a few hours, or by adding a small pinch of salt for each quart of water boiled. 
  2. Chemical treatment: When boiling is not practical, chemical disinfection should be used. The two chemicals commonly used are chlorine and iodine. If applied with care, certain chemicals will make most water free from harmful or pathogenic organisms.

What is a Boil Water Advisory?

A boil water advisory, issued by the owner or operator of a public water system or by DEQ, notifies water system users that the water may be contaminated and to boil the water prior to using it for drinking or cooking until further notice. The advisory will also give the reason for its issuance and which corrective actions are being taken. The most common drinking water emergency is contamination by disease-causing germs. Boiling your water for 1 minute will kill these germs.

How can I get my drinking water tested?

Public water systems routinely monitor for commonly found contaminants, so the chance that your water is contaminated is very low. If you think you have a problem with your water, contact your local water system right away to discuss any concerns. If the system owner or operator is unavailable, contact your nearest DEQ regional office.

If your home is served by a community water system, get a copy of your annual water quality report (CCR) before you pay to test your water. This report will tell you which contaminants, if any, have been found in your drinking water and at what levels. You are always free to conduct additional sampling for your residence; however, in most cases this is not necessary.

Without knowing what to look for, the cost of testing drinking water on a hit or miss basis can be very high. Depending on how many contaminants you test for, a water test can cost from $15 to hundreds of dollars. If you tested for all possible contaminants, testing costs could reach into the thousands of dollars.

Is there a generic drinking water test for everything?

No. Each possible contaminant must be evaluated individually.

Does Idaho or EPA perform testing for water systems or individual homeowners?

No, but the Idaho Bureau of Laboratories maintains a directory of laboratories certified to test your drinking water. Link to Drinking Water Laboratory Certificates here.

My water looks and smells awful, but my water supplier says its is safe to drink. How is that possible?

Sometimes water may look or smell bad and still be safe. Even when water meets EPA standards, you may still object to its taste, smell, or appearance. Your water is tested regularly for bacteriological content. Compounds such as iron, manganese, and other sediments may give your water the appearance of being dirty without affecting its microbiological quality. If you think you have a problem with your water, contact your local water system right away to discuss any concerns. If the system owner or operator is unavailable, contact your nearest DEQ regional office.

My water smells like chlorine. What do I do?

Each individual water system regulates its own use of chlorine to disinfect water.  If you dislike the taste or smell of chlorine in your water, make the water more palatable by exposing it to the air for a few hours or by pouring it several times from one clean container to another.

What could cause my tap water to have a rusty color?

Fire hydrant flushing and water main repairs can disturb sediments in water mains, resulting in red- or brown-colored tap water. If you detect red or discolored water, turn on a single COLD water tap for a few minutes to flush any sediment out of your pipes. While red or discolored water is not a health concern, it can stain laundry. 

If my water is blue-green, what does that mean?

Blue-green water could be an indicator of high copper levels. To discuss the problem, first contact your water supplier. After talking to your supplier, you may also want to contact your DEQ regional office for more information.

How do I know if there is lead in my drinking water?

Lead is found almost everywhere: in food, paint, dust, soils, air, and drinking water. Lead is rarely in drinking water when it leaves the treatment plant. Instead, it leaches into the water from some plumbing in buildings and homes (e.g., new plumbing fixtures) and especially from older structures that still have lead pipes. Children and pregnant women are most susceptible to health risks from lead in drinking water.

Bottled Water

Is bottled water safer than tap water?

Bottled water is not necessarily safer than your tap water, although it is almost always significantly more expensive. EPA sets standards for tap water provided by public water systems; the Food and Drug Administration sets bottled water standards based on EPA's tap water standards.

Bottled water and tap water are both safe to drink if they meet these standards, although people with severely compromised immune systems and children may have special needs. Some bottled water is treated more than tap water, while some is treated less or not treated at all. Bottled water costs much more than tap water on a per gallon basis. Bottled water is valuable in emergency situations (such as loss of pressure and floods), and high quality bottled water may be a desirable option for people with weakened immune systems. Consumers who choose to purchase bottled water should carefully read its label to understand what they are buying (e.g., determine the water source and treatment method).

Private Wells

Do I need to have my private well tested?

Private wells should be tested annually for nitrate and coliform bacteria to detect contamination problems early. Although testing is not required, it can be a reasonably prudent step to take to protect your family. Check with your public health district to learn more about well water quality in your area and which contaminants you are more likely to find and need to test for.

If you have your own well, you are responsible for ensuring that your water is safe to drink. In short, protecting your drinking water comes down to frequent testing and adequate wellhead protection. You can protect your water supply by carefully managing activities near the wellhead. For example, do not store hazardous chemicals near the wellhead; avoid mixing or using pesticides, fertilizers, herbicides, fuels, and other pollutants near the well; determine how close your septic tank is to the water well; and install a well cap or sanitary seal to prevent unauthorized use of, or entry into, the well.

How do I arrange to have my private well tested?

Your public health district and DEQ regional office are good sources of information about testing and protecting your well. Have your water tested and analyzed by a certified laboratory. The certified laboratories will furnish you with the testing bottles and instructions for taking water samples. Set up a routine testing schedule. Laboratories conducting tests for nitrate and bacteria samples will typically charge between $10 and $20 to complete. You may want to test for these more frequently and for other contaminants, such as radon or pesticides, if you suspect a problem. Testing for other contaminants will be more expensive. For example, testing for pesticides or organic chemicals may cost from several hundred dollars to several thousand dollars.

Home Treatment Units

Do I need a home treatment unit?

Most people served by a public water system do not need to treat their drinking water at home to make it safe. If you have a private water supply, it is your responsibility to test your drinking water and to ensure that it is safe. Your test results may help determine if you need a home treatment unit.

A home water treatment unit may improve the taste of water, or provide an extra margin of safety for people more vulnerable to the effects of waterborne illness (people with severely compromised immune systems and children that may have special needs).  

Consumers who choose to purchase a home water treatment unit should shop around first. Carefully read the product information to understand what you are buying before purchasing. No single unit takes out every kind of drinking water contaminant; you must decide which type best meets your needs. Once purchased, follow the instructions provided by the manufacturer for operation and maintenance, and change the filter on a regular basis.




Staff Contacts

Drinking Water Program Manager
Jerri Henry
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0471

Related Pages

Private Wells