Lake Powell is one of the largest man-made reservoirs in the U.S.A. With 96 side canyons, nearly 2,000 miles of shoreline, high summer temperatures, and fluctuating reservoir levels, its waters experience a wide range of water quality conditions.
A number of conditions can cause potential water quality issues, including elevated Escherichia coli (E. coli) counts, on Lake Powell, at Lees Ferry, and on Colorado River tributaries. These include:
High visitation at beaches, at popular houseboat sites, and at other frequently visited areas.
Rising reservoir waters that come in contact with previously deposited human waste, pet waste, and livestock manure.
Headwaters of the many canyons along the lake (that are experiencing snow melt, rainwater runoff, or intense monsoonal storms coming from the plateaus and mountains) can pick up E. coli from livestock and wildlife waste and transport it to the reservoir.
Frequently visited areas (Antelope Canyon, areas near Lone Rock, popular house boat and accessible shoreline beaches, etc.) where visitors fail to use portable toilets, wag bags or other approved waste disposal methods.
Illegal dumping of septic tanks from private houseboats and larger recreational boats with bathrooms. All rental houseboats are now outfitted to not allow illegal dumping.
Sandy areas and water frequently used by wildlife such as geese, gulls, ducks, ravens, herons, coyotes, rabbits, and desert bighorn sheep can harbor E.coli.
Slot canyons, water pockets, and beach areas with warm pools of water cut off from flowing water or the reservoir can be hotspots for E.coli from wildlife, visitors, or other sources. These are often areas where children prefer to play – help steer them away from these areas and ensure their hands are washed before they eat.
Anytime that you do recreational activities (swimming, water skiing, making sand castles, etc.) on the beaches or in the waters of Lake Powell you are strongly encouraged to follow basic hygiene practices:
Do not ingest the water
Wash your hands before eating and touching your eyes or mouth
Shower with soap after participating in any water activities
Wash your hands after handling fish, gathering up your water gear and toys, changing out of your swimming suit, etc.
Do not enter the water if you have open sores or cuts or if you are currently sick with diarrhea as one of your symptoms
Be On The Watch For Signs of Harmful Algal Blooms
With warm summer water temperatures and plentiful nutrients from monsoonal storms there is a possibility that conditions leading to Harmful Algal Blooms (HABs) may develop. HABs occur when normally occurring cyanobacteria in the water multiply quickly to form visible colonies or blooms. These blooms sometimes produce potent cyanotoxins that pose serious health risks to humans and animals. Stay out of the water and avoid any contact with water or scums if you see pale-green or pea-green scum on or in the water and suspect a waterbody is experiencing a harmful algal bloom.
Report potential harmful algal blooms to an NPS ranger, to the AIS staff inspecting boats at the boat ramp, or to NPS staff at the visitor centers. You can also call and leave a message at 928-608-6539 noting the canyon and/or location on the lake.
How to stay safe during HABs
Don’t swim in water that has an algal bloom.
Don’t boat, water ski, or jet-ski on scummy water. These activities can cause toxins to become airborne, increasing the likelihood you will inhale them.
Don’t let children play with scum in the water or along the shore.
Don’t let pets or livestock swim in or drink from scummy waters.
Always take a shower after coming into contact with any surface water whether or not an algal bloom appears to be present. Rinse/wash animals immediately if they swim in scummy water and don’t let them lick their fur.
Recreational Water Illnesses
Swimming pools, spas, lakes, reservoirs, rivers, slot canyon pools, and sandstone tanks full of water are all potential sources of recreational water illnesses. Recreational water illnesses typically affect a person's stomach and intestines, skin, or respiratory system. If you think you have a recreational water illness that needs medical attention, contact your health care provider.
Stomach and Intestinal Illness
Gastrointestinal illnesses affect a person's stomach and intestines, and can cause diarrhea, nausea, or vomiting. The following gastrointestinal illnesses have been associated with recreational water activities.
Crypto is one of the most common causes of water recreation diarrhea illness in the United States. The germ is found in people's stool. It's highly resistant to chlorine disinfection and can survive in a pool for as long as ten days. Swallowing contaminated water is how people are often infected. To help stop the spread of Crypto, people with diarrhea shouldn't go swimming. Giardia
Giardia is another common cause of diarrhea found in infected people's stool and beaver are a common carrier. It can take about 45 minutes for this germ to be killed by chlorine disinfection in pools. You shouldn't swim if you have diarrhea and you should always avoid swallowing water while swimming. Shigella
Shigella causes severe diarrhea, which is often bloody. It can be spread if an infected person with diarrhea swims or plays in areas such as beaches or inadequately disinfected pools. Having hand washing stations with soap near swimming areas helps keep the water from becoming contaminated. E. coli O157:H7
People can get an E. coli infection by swallowing lake water while swimming. Symptoms are similar to Shigella and include severe diarrhea and bloody stool. This infection can be life-threatening and cause permanent damage to the kidneys. Swimming at contaminated beaches are potential sources of infection. Norovirus
Noroviruses are very contagious and can spread through an infected person's stool or vomit. The illness often begins suddenly and usually includes nausea, vomiting, diarrhea, and stomach cramps. Chlorine disinfection helps kill this virus in pools, but lakes and beaches can be contaminated. Avoid swallowing water while swimming to help prevent infection.
Skin rashes, boils, allergic reactions to chemicals, and skin damage from the sun can occur when enjoying water recreation activities.
Hot Tub Rash - Pseudomonas dermatitis / Folliculitis
Hot Tub Rash or dermatitis is an infection that causes an itchy bumpy rash on the skin. The rash usually occurs within days of swimming in poorly maintained hot tubs or spas, but can also be spread by swimming in a contaminated pool or lake. Properly maintaining hot tubs and pools helps eliminate the germ that causes this rash.
Swimmer's Itch - Cercarial dermatitis
Swimmer's itch is a rash caused by an allergic reaction to parasites that typically infect some birds and mammals. The parasites come from infected snails which live in lakes, ponds, and oceans. People are not suitable hosts for the parasite's life cycle, so after burrowing into a swimmer's skin, the parasite soon dies. Reduce your risk by not swimming in area's known to have a swimmer's itch problem or where snails are commonly found, and showering or towel drying immediately after leaving the water.
Swimmer's Ear - Otitis externa
Swimmer's ear is an infection of the outer ear canal and can affect anyone, but is most common in children. Symptoms usually start a few days after swimming and include ear pain, itchiness, redness, swelling, and pus draining from the infected ear. It can be treated with antibiotic ear drops. Swimmer's ear is caused when water stays in the ear canal for long periods of time, allowing germs to grow and infect the skin. When swimming, try to keep ears dry.
Cyanobacteria – Harmful Algal Blooms
Cyanobacteria, or blue-green algae, are found in lakes, rivers, ponds, and seawater. Sometimes cyanobacteria is toxic and people can experience skin, eye, or ear irritation with contact. If toxic cyanobacteria is swallowed, it can cause stomach cramps, vomiting, diarrhea, sore throat, fever, headache, muscle and joint pain, or nerve and liver damage. Avoid swimming in or having contact with algal blooms. Don't let pets drink or swim in waters with algal blooms.
Some people can experience allergic reactions, such as skin redness and itching, to chemicals used in pools. The reactions commonly occur within an hour or two of being in the water. It's also possible that improper use of chemicals or a chemical release at a pool could expose people to skin or respiratory irritants.
Some water recreation illnesses can affect a person's breathing causing cold or flu-like symptoms, shortness of breath, cough, or a serious infection in the windpipe or lungs.
Legionnaire disease is a serious infection that creates life threatening pneumonia. Another less serious form of the infection is Pontiac fever, which has the same early symptoms of Legionnaire disease (body pain and weakness, headache, fever, chills, and cough) but isn't associated with pneumonia or death. The germ that causes the disease can be found in streams, ponds or in man-made structures such as fountains or spas. People are typically infected by breathing in contaminated water vapor or steam. Proper maintenance of pools and spas helps eliminate this germ.
Are you tired of seeing your fellow boaters dump their trash and human waste on beaches? Did you find graffiti carved on canyon walls or other damage to the landscape? Help us out on Lake Powell by being part of our neighborhood watch program.
If you see any resource damage or illegal activities, send an email to our Dispatch Center, who can process accordingly and notify law enforcement. If you can, include coordinates and/or photos with your report. Send to GLCA_Dispatch_Center@nps.gov.
This is an information only platform. In an emergency, call 911 or hail National Park Service on Marine Band 16.
Nothing is better on a hot summer day than a dip in the clear waters of Lake Powell.
Last updated: March 21, 2023
PO Box 1507
Receptionist available at Glen Canyon Headquarters from 7 am to 4 pm MST, Monday through Friday. The phone is not monitored when the building is closed. If you are having an emergency, call 911 or hail National Park Service on Marine Band 16.