If you or someone in your family has consumed water that might have had high levels of cyanotoxins and you are feeling sick, please talk to your doctor. The Centers for Disease Control and Prevention (CDC) is collecting information about illnesses related to these toxins. To report an illness caused by cyanotoxins in people or animals, please contact your state or local health department.

The Health Advisory levels for microcystins and cylindrospermopsin for concentrations where we do not expect any health problems after drinking the water for 10 days. Since it can be hard to know how long harmful algae toxins will be high, the U.S. Environmental Protection Agency (U.S. EPA) suggests that water systems start taking action as soon as they confirm these high levels with more tests. Also, because it takes time to process these tests, it may take several days to confirm if the water has toxin levels above the Health Advisories after a bloom or cyanotoxins are found. Therefore, the U.S. EPA advises starting response actions as soon as possible.

Reducing nutrient pollution, like too much nitrogen and phosphorus, is important for lowering cyanotoxins in drinking water sources. Extra nutrients can come from farms, factories, cities, and even the air. You can help reduce nutrients in water by using phosphate-free detergents, properly disposing of pet waste, using fertilizers only when needed and in the right amounts and volunteering to protect local watersheds. For more ways to help, visit https://www.epa.gov/nutrientpollution/what-you-can-do.

The U.S. Environmental Protection Agency (EPA) created 10-Day Health Advisories for the cyanotoxins microcystins and cylindrospermopsin (see Table 1). There are two separate Health Advisories: one for infants and children under six years old and one for adults and children six years and older. These advisories are based on the latest science and focus on exposure over a 10-day period. For more information, visit https://www.epa.gov/nutrient-policy-data/drinking-water-health-advisory-documents.

The U.S. Environmental Protection Agency (EPA) creates Health Advisories for unregulated contaminants to help states and water systems handle local issues, emergencies and spills. These advisories are not federal laws or enforceable limits. They show the contaminant levels at or below levels that are unlikely to harm human health over a certain period of time. The EPA may update these advisories as new information becomes available.

Harmful Algal Blooms that produce cyanotoxins can happen in water used for drinking. If these toxins are not removed during water treatment, they can be harmful to people if found in tap water above certain levels. Algal blooms can also cause taste and smell issues in drinking water, like an earthy or musty odor. However, these smells and tastes are not harmful to your health.

Drinking water with elevated levels of cyanotoxins can be harmful if used in dialysis treatment. The U.S. Environmental Protection Agency (EPA) advises dialysis centers and people using dialysis at home to use a different water source if their current water is contaminated with high levels of cyanotoxins. Talk to your local health department or your doctor for guidance.