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Idaho DEQ: Current Water Quality Health Advisories in Idaho

Idaho Dept. of Health and Welfare: Safe Water Resources

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2022 Impacts & Advisories for Ada, Elmore, Boise, and Valley Counties

No harmful algal bloom (HAB) advisories have been issued for water bodies in Ada, Boise, Elmore and Valley Counties at this time. Residents are encouraged to watch the above video from the Idaho Department of Environmental Quality (DEQ) to learn more about HABs and how to identify them.

It's important to know that surface water can still be unsafe for humans and animals even if an advisory is not in place. Not all algal blooms are harmful, but sampling conducted by DEQ is limited, so when it doubt, stay out.

To report a suspected HAB to DEQ, visit this link.

For a map of current statewide harmful algal blooms and related health advisories, click here.

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HARMFUL ALGAL BLOOMS (HABs): WHAT TO KNOW

Most of the year, Idaho's beautiful lakes, reservoirs and ponds are safe to enjoy. However, when water temperatures rise and the right type of nutrients are available, some bodies of water can produce Cyanobacteria which can produce harmful algal blooms (HABs). These blooms can pose health risks to humans, pets, livestock, and wildlife. 

In Idaho, only a fraction of all water bodies are monitored due to limited physical and monetary resources. The absence of an advisory is not an indication that a HAB or E. coli is not present at a water body. You are your own best advocate when ensuring your safety, and that of your family and pets. Be aware and "when in doubt, stay out."

What is a Harmful Algal Bloom?

Cyanobacteria occur naturally in the environment and are a vital part of the ecosystem. A harmful algal bloom occurs when excessive growth cyanobacteria exists, which has the potential to produce toxins. Abundant nutrients (phosphorus and nitrogen), sunny conditions, warm temperatures, and low-flow or low-water conditions can contribute to exponential growth resulting in algal blooms.

Appearance

Blooms can vary in appearance, sometimes looking like mats, foam, or surface scum — especially near the shoreline. Blooms can range in color from blue and bright green to brown and red. Some blooms produce a foul odor.

Blooms can occur at any time, but they most often occur in late summer or early fall. Often in association with a HAB, you may hear reference to cyanobacteria.

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IMPACTS TO HEALTH

Not all blooms are toxic, but when toxic harmful algal blooms do occur they present a health risk to humans, pets, and livestock. Exposure may occur from ingestion, skin contact, or inhalation. Exposure can result in a range of health effects from skin irritation and stomach upset or pain to neurotoxic effects and at very high levels, death.

The most common health effects are skin and eye irritation. Other more severe health effects can include:

Difficulty breathing
Stomach pain
Nausea
Vomiting
Diarrhea
Dizziness
Numbness and tingling in lips, fingers, and toes

Symptoms in humans and pets can occur within minutes of exposure but may take as long as 36 hours to develop depending on the particular toxin and its concentration (CDC 2016). Anyone with symptoms should seek medical attention.

Call your pet's veterinarian immeditely if your pet has been around an algal bloom and shows symptoms such as vomiting, staggering, drooling or convulsions.

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HEALTH ADVISORIES

When a harmful algal bloom is suspected, the Idaho Department of Environmental Quality (DEQ) will collect a water sample from the affected water body and send it to a lab for analysis. Health advisories are issued for a water body when the number of cells in the water is above a level recommended as unsafe for recreating.

When a health advisory is issued, is the entire water body unsafe for recreational use?

Algae blooms are known to be very patchy in nature. Higher densities may be present in areas not surveyed, particularly along shorelines. The density of a harmful algal bloom can change with wind direction and temperature. Regardless of whether a health advisory is in effect, recreational users should avoid contact with water whenever surface concentrations of cyanobacteria are evident or when the lake has scums with obvious green to blue-green appearance.

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PROTECT YOURSELF AND PETS

People and animals can be exposed to HABs by swallowing water and/or touching the water during recreational activities such as swimming, water skiing, and diving.

The following precautions are recommended when an advisory is in effect. However, whether or not a health advisory is in place, if the water looks questionable, the best advice is, when in doubt, stay out.

Avoid exposure to water experiencing a harmful algal bloom. Take extra precautions to ensure children, pets, and livestock are not exposed to the water.

Do not consume water with a harmful algal bloom. Neither boiling nor disinfecting removes the toxins from water.

If fish are known to have been exposed to a harmful algal bloom, only consume the fillet portion (remove the fat, organs, and skin). Wash hands after handling. The risk associated with consuming fish caught in waters with a harmful algal bloom is unknown. Toxins produced by a harmful algal bloom can accumulate in the organs of fish.

Symptoms can occur within an hour of exposure but may take as long as 36 hours to develop depending on the particular toxin and its concentration (CDC 2016). Anyone with symptoms should seek medical attention. If you experience mild irritation, rinse with clean water immediately.

If your pet comes in contact with a bloom, rinse them with clean, fresh water immediately. If severe symptoms occur, call a veterinarian immediately. In severe cases, animals may die within tens of minutes to hours after they have been exposed to harmful algal blooms. When harmful algal blooms decompose, they can also kill fish that live in the water.  

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How to Report Potential HABs

In Idaho, only a fraction of all water bodies are monitored due to limited physical and monetary resources. The absence of an advisory is not an indication that a HAB or E. coli is not present at a water body. You are your own best advocate when ensuring your safety, and that of your family and pets. Be aware and "when in doubt, stay out."

You can help report potentially harmful algal blooms in Idaho:
Idaho DEQ - Bloomwatch Reporting Site

Resources

Frequently Asked Questions on HABs
Idaho DEQ: Harmful Algal Blooms
Idaho Health & Welfare: FAQs About Harmful Algal Blooms
Protect Your Pets

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PAST HEALTH ADVISORIES

2021 Impacts & Advisories for Ada, Elmore, Boise, and Valley Counties

October 8, 2021: Health Advisory Lifted for Cascade Reservoir

Ada County, Idaho – Central District Health (CDH), in conjunction with the Idaho Department of Environmental Quality (DEQ), have lifted a public health advisory for Cascade Reservoir, located in the Valley County community. The advisory was issued on August 13, 2021 due to the presence of cyanobacteria, also known as a Harmful Algal Bloom (HAB). After regular monitoring, and water sample collection and testing, DEQ confirmed levels have returned to normal and toxin levels are below the safety threshold.| Read more

August 27, 2021: DEQ conducts additional sampling at Payette Lake

Valley County, Idaho – A second round of water quality sampling at Payette Lake confirmed normal levels of cyanobacteria consistent with high water quality. Final lab results are expected soon following a comprehensive analysis at a national lab that specializes in identifying cyanobacteria and their cyanotoxins. The Idaho Department of Environmental Quality will share that information with the public as soon as it’s available. DEQ collected samples at three Payette Lake locations, including the western edge of North Beach, a northwestern portion of the lake, and a section between Brown Park and Mile High Marina. | Read more

August 20, 2021: Additional water testing planned at Payette Lake in response to recent public reports

Valley County, Idaho – Central District Health (CDH) is sharing information about upcoming water sampling and testing planned for Payette Lake by the Idaho Department of Environmental Quality (DEQ). On Tuesday, August 17, 2021, DEQ collected water samples from Payette Lake as a follow up to public concern regarding a dog that became ill after it had spent time in the lake. Test results did not indicate the presence of the most common types of cyanobacteria found in Idaho surface water. However, additional information from veterinarians who treated the dog indicate the dog's symptoms likely align with neurotoxin exposure. Neurotoxins can be associated with surface water and cyanobacteria (or Harmful Algal Blooms, HABs), among other sources. New water samples will be collected by DEQ on Monday, August 23, 2021, and will be sent to an out-ofstate lab for additional testing to determine if different types of cyanobacteria or cyanotoxins than those most commonly seen in Idaho could be present in the lake. Once more information is known, it will be shared with the public. It is possible that lab results will be received by Wednesday, September 1, 2021.

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August 13, 2021: Central District Health issues public health advisory for Cascade Reservoir in Valley County due to Harmful Algal Bloom
Central District Health (CDH), in conjunction with the Idaho Department of Environmental Quality (DEQ), has issued a public health advisory, effective immediately, for Cascade Reservoir due to the presence of cyanobacteria, also known as a Harmful Algal Bloom (HAB). DEQ will continue conducting surveillance through satellite imagery, on-site observation, and will continue with weekly water sampling of Cascade Reservoir.People and animals can get sick if they swim, wade, or play in or near HAB-contaminated water, eat contaminated fish, shellfish, or use contaminated drinking water. | Read the Advisory

July 12, 2021: Swimmer's itch cases have recently been reported after people swam at the South end of Lake Cascade and at Horsethief Reservoir in Valley County. Swimmer's itch is an itchy rash that can occur after you go swimming our wading outdoors. Within minutes to days after swimming in contaminated water, you may feel tingling, burning or itching of the skin. It can be uncomfortable, but it usually clears up on its own in a few days. Learn more about swimmer's itch HERE.

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2020 Impacts & Advisories for Ada, Elmore, Boise, and Valley Counties

11/25/20: Health advisory lifted for Cascade Reservoir
Central District Health (CDH) and the Idaho Department of Environmental Quality (DEQ) have lifted a health advisory for Cascade Reservoir in Valley County. The advisory was issued on October 5, 2020, due to a harmful algal bloom (HAB). After regular monitoring, and water sample collection and testing, DEQ has confirmed that levels have returned to normal and toxin levels are below the safety threshold.

Read 11/25/20 Advisory Lifted Release | Read 10/5/20 Advisory Issued Release

10/29/20: Health advisory lifted for CJ Strike Reservoir
Central District Health (CDH), Southwest District Health (SWDH), and the Idaho Department of Environmental Quality (DEQ) have lifted a health advisory for CJ Strike Reservoir, which has access points in both Owyhee and Elmore Counties. The advisory was issued on September 18, 2020 due to a harmful algal bloom (HAB). After regular monitoring, and water sample collection and testing, DEQ confirmed levels have returned to normal and toxin levels are below the safety threshold.

Read 10/29/20 Advisory Lifted Release | Read 9/18/20 Advisory Issued Release

8/24/20: Health Advisory Lifted for Silver Lake in Boise
Central District Health (CDH) and the Idaho Department of Environmental Quality (DEQ) have lifted a health advisory for Silver Lake, located in Northwest Boise’s Lake Harbor community. The advisory was issued on April 29, 2020 due to a harmful algal bloom (HAB). After regular monitoring, and water sample collection and testing, DEQ confirmed levels have returned to normal and toxin levels are below the safety threshold. | Read More | 4/29/20: Health Advisory Issued for Silver Lake

6/29/20: Elmore County - Long Tom and Mountain Home Reservoirs are showing signs of potential Harmful Algal Blooms (HABs). As a reminder, HABs can sometimes look like mats, foam or surface scum and can range in color from blue and bright green to brown and red. They can make you and your pets sick, so when in doubt, stay out! Report suspected HABs at cyanos.org/bloomwatch/.

2019 Lifted Advisories

• 9/6/2019 - Health advisory issued for Lake Cascade in Valley County - Lifted on 11/4/2019
• 8/16/2019 - Health advisory issued for Little Camas Reservoir in Elmore County - Lifted on 11/26/2019
• 7/31/2019 - Health advisory issued for Mountain Home, Indian Creek and Blacks Creek Reservoirs - Lifted on 11/26/2019

2018 Lifted Advisories

• September 7, 2018: Lake Cascade (CDH Health Advisory)
  ** Health Advisory Lifted 10/16/2018
• September 25, 2018: Boise's Esther Simplot Ponds No. 1 and No. 2
  ** Re-opened 10/8/2018
• June 23, 2018: Little Camas Reservoir | Elmore County
  ** Advisory Lifted 9/20/2018 - Water has receded for the season
• July 25, 2018: Eagle Island State Park (CDH Health Advisory)
  ** Pond Re-Opened on 8/3/2018
• July 24, 2018: Horsethief Reservoir | Valley County
• ** Levels did not necessitate closure
  
• July 20, 2018: Esther Simplot Park, Pond 1 | Ada County
  ** Pond Re-Opened on 8/2/2018
• July 18, 2018: Eagle Island State Park - Parks News Release | Ada County
  ** Pond Re-Opened on 8/3/2018