Beach Testing & Water Quality

We test beaches for E. coli bacteria, using Environmental Protection Agency standards. The most common germs found in water are bacteria, viruses, or parasites from human or animal feces. These germs can make you sick. 

Testing for all the germs in the water is time consuming and expensive. We test for E. coli because it is the best indicator if there are other germs in the water that can make you sick. 

We begin testing water at public beaches before Memorial Day, and stop testing around Labor Day.  

We test beaches weekly, unless we get a result that is above the safety standard. If that happens, we increase testing at impacted beaches until they reach safe levels again.

• We will close a beach when our monitoring shows that the level of E. coli  bacteria is very high, or when algae scum is found. Algae scum happens when algae forms layers or “mats” on the surface of the water (the water may look bubbly and/or frothy). Algae scum means it’s more likely there are high levels of harmful algae toxins in the water.

• In some situations, we will post a water quality advisory instead of closing a beach. We post an advisory if our monitoring shows elevated levels of E. coli bacteria and there is an increased risk of illness or if monitoring suggests there’s a greater risk of harmful algae toxins in the water, but an algae scum isn’t present. We also post an advisory if we see visual signs that a harmful algae bloom may happen soon.

• Closures and advisories stay in effect until bacteria/algae levels return to lower levels. We test all closed beaches daily until bacteria or algae toxin levels drop to an acceptable level.

• We post daily updates on our social media pages and on this webpage when a beach is closed. Note: If a beach is closed on a Friday, it will remain closed throughout the weekend. We do not test beach samples on weekends.

Beach closure: We close a beach when our monitoring shows that the level of E. coli bacteria is very high, or when we find an algae scum, which means there’s a greater risk of harmful algae toxins in the water and air. 

Water quality advisory: Posted when our monitoring suggests that there’s a greater risk of harmful algae toxins, but an algae scum isn’t present on the water. 

• Remember that water conditions can change quickly. Water quality signs posted at the beach may not always reflect real-time conditions.
• If you see signs of a harmful algae bloom at any Oneida County public beach, please call us at 715-369-6111.

Water quality advisory: We post an advisory if our monitoring shows elevated levels of E. coli bacteria and there is an increased risk of illness.

During a beach closure, the beach is closed for ALL water recreation activities. Stay out of the water.

• If you see a harmful algae bloom, avoid the beach area to prevent breathing in toxins from air near the beach.
• Do not boat, kayak, or water ski in water with a harmful algae bloom.
• Do not let children play with scum layers, even from the shore.
• Do not let pets or other animals swim in or drink water with a harmful algae bloom.

During a water quality advisory, we recommend that you stay out of the water – don’t swim in, boat in, touch, or swallow the water.

If you do choose to use the water: try to find an area where algae are not present, shower after swimming, don’t ingest the water, and wash your hands before eating.

• Many factors can influence water quality, including:
  • Recent weather conditions, like wind or rain
  • Time of day
  • Birds and wildlife at the beach
  • Number of people at the beach
  • Physical characteristics of the beach
• Conditions can significantly vary hour-to-hour and day-to-day.
• We don’t recommend swimming right after a heavy rainfall because bacteria levels in the water may be high.
• Before swimming, ALWAYS take an overall look at the water. Conditions can change quickly, and test results and/or signs posted at the beach may not always reflect real-time water quality. You can’t always see or smell when water conditions are poor.

When environmental conditions are right, the algae population can grow quickly and produce a “bloom.” A bloom is a sudden, rapid increase in algae cells in an area of water.

If there is little wind, warm water, sunlight, and plentiful nutrients (especially phosphorus), there is a higher chance that a bloom will appear. Warm weather and heavy rain that washes agricultural and residential fertilizers (which contain phosphorus) into the water can also jump-start a bloom.

In Wisconsin, blooms typically happen between mid-June and mid-September. Wisconsin lakes and rivers can become cloudy with rapidly reproducing algae.

Not all of them. There are many species of algae found in Wisconsin lakes and rivers, but only certain species can produce the dangerous algae toxins (or make enough toxins) to make people and pets sick. Larger algae blooms are more likely to have higher levels of toxins.

When you see an algae bloom, avoid those areas of the water. It is impossible to tell if an algae bloom is toxic just by looking. The safest thing to do is to treat every bloom as if it could be dangerous.

Check out this fact sheet about telling the difference between harmful and non-harmful algae: https://www.dhs.wisconsin.gov/publications/p01888.pdf

• An active bloom may look like “pea soup”, or green or blue paint. It may have a scum layer or puffy blobs floating on the surface.
• Harmful blooms are most often blue-green in color, but can also be reddish-purple or brown. The water may also appear murky.
• Harmful algae will follow sunlight and nutrients by floating to the surface. There it can form thick scum layers or mats, and the surface may look bubbly or frothy. Algae scums can be pushed to different locations by wind or tide.
• Check out this fact sheet:  https://www.dhs.wisconsin.gov/publications/p01888.pdf

• Don’t swim or wade through algae scums.
• Don’t let dogs drink lake water during an algae bloom.
• Don’t let dogs eat algae scum or lick it off their fur.
• Wash your dog off with clean water immediately if they swim or wade in water during an algae bloom.
• Don’t boat, water ski, or jet ski through algae blooms.
• Don’t fish in any part of the lake where you can see algae scum.
• Always shower off with soap and water after swimming in a lake.
• Call us at 715-369-6111 if you see signs of a harmful algae bloom at any Oneida County public beach.

• Potential health effects include irritation of the skin, eyes, nose, throat and/or respiratory tract.
• Swallowing water with harmful algae blooms or toxins can cause nausea, diarrhea, and vomiting.
• Swallowing contaminated water with toxins has also been associated with negative effects on the liver and nervous system.

• If you, your child, or your pet are experiencing symptoms that you think are related to exposure to harmful algae, call your doctor or the Wisconsin Poison Center (800-222-1222) right away.
• Also report the illness by calling the Wisconsin Department of Health Services Harmful Algal Blooms Program (1-608-266-1120) or by completing this online survey.

• Animals are not necessarily more sensitive to harmful algae bloom toxins than humans. However, many animals, including dogs and cattle, enjoy being in the water – even if there is a smelly, green scum layer floating on top.
• When a harmful algae bloom is happening, animals may consume large amounts of harmful algae if they drink the water. If those harmful algae happen to be producing toxin(s), the animals can become very ill or die.
• Harmful algae toxin poisoning symptoms can range from lethargy and loss of appetite to seizures, vomiting, and convulsions. Dogs may be more likely to get harmful algae poisoning because scum can attach to their coats and can be swallowed during self-cleaning.
• If your pet has symptoms like seizures, vomiting, or diarrhea after contact with surface water, call your veterinarian right away.

YES. Children may be at greater risk than adults for two reasons:

• Children love to play in the water, and may swallow the water because they’re thirsty, or accidentally while swimming.
• Children weigh less, and a smaller quantity of algae toxin(s) can cause negative symptoms.

Swallowing beach water with high levels of bacteria is most likely to cause flu-like symptoms, including diarrhea, nausea, fever and abdominal cramping.

Coming into contact with water that has elevated bacteria levels may cause swimmer’s itch. Swimmer’s itch can cause tingling, burning, or itching of the skin, small reddish pimples, or small blisters. Symptoms typically start a few days after exposure and may persist for several days to weeks. The length and severity of symptoms can vary.

We recommend not to swim until an open wound, or recent tattoo or piercing is completely healed to avoid an infection.

• Evidence so far suggests that eating the muscle tissue, known as the fillet, of a fish caught before, during, or after a harmful algae bloom poses low risk to human health. However, consuming the fish whole, including it’s organs, could be harmful to health. This is because cyanotoxins are more likely to build up in internal organs such as the liver and kidneys, and not the fillet. To date, there have been no known reports of people getting sick from eating fish caught during a freshwater bloom, however, more research is needed to better understand the risk to human health, especially for long-term consumption of fish impacted by harmful algae. Currently, there are no state health-based guidelines for consuming fish from water affected by a harmful algae bloom. 
• If you decide to catch and eat fish from bloom-affected water, follow these tips:
  • Avoid touching bloom-affected water. If your skin is exposed, wash it off with clean water.
  • Remove the internal organs and fat since these are the parts of the fish that are most likely to build up toxins. Be cautious not to cut into the organs. 
  • Thoroughly rinse the fillet with clean water before cooking or freezing to remove any excess contaminants.
• Avoid fishing in water with an algae bloom to prevent having to handle fish and fishing gear that contain harmful algae.
• For more information about safe fishing practices and fish consumption, visit  https://www.dhs.wisconsin.gov/publications/p03625.pdf.

Eating fish and other seafood is beneficial for your health. However, due to the potential for contamination, it is important that you eat fish in recommended amounts.

The Health Department does not test fish for any contaminants, but fish are occasionally tested by state agencies. Find more information on the Department of Natural Resources website and the Department of Health Services website.

Yes. We monitor for harmful algae (also called cyanobacteria) using safety guidelines set by the World Health Organization.

If conditions are right, harmful algae can “bloom” in lakes and other bodies of fresh water. These blooms can be toxic to people, children, and animals.

A water quality advisory or closure sign may be posted up to two days after a harmful algae bloom disappears, since toxins may still remain in the water and can make people (especially children) and pets sick.

If you see a harmful algae bloom, call us at 715-369-6111 to report it.