Clean drinking water is essential for our health, whether it comes from a public water system or a private well. Having pristine lakes, rivers, and streams also supports our health. The Missouri Environmental Public Health Tracking (EPHT) Program provides data on water quality in Missouri.
Drinking Water
How is Drinking Water Tested?
Public water systems monitor public drinking water for contaminants, like chemicals and bacteria, on a regular basis. The Missouri Department of Natural Resources oversees public water systems to make sure our public water is safe to drink. The amount of a chemical in the water is compared to the highest amount allowed by the U. S. Environmental Protection Agency (also called the Maximum Contaminant Level or MCL).
Private well water testing is the responsibility of homeowners. If you have a private well, DHSS recommends you test it at least once each year; anytime the well is serviced; or if you notice a change in the look, smell or taste of your water. You can learn more about private well testing from the DHSS Private Drinking Water Program.
Drinking Water Data
The Missouri EPHT Program provides data on public and private drinking water in Missouri.
Search this query to find:
Annual mean concentrations of contaminants in public water systems
Quarterly mean concentrations of contaminants in public water systems
Annual maximum concentrations of contaminants in public water systems
Number of public water systems with chemical concentrations above or below the MCL, and population served by those water systems
Percent of public water systems with chemical concentrations above or below the MCL, and percent of population served by those water systems
Other Data Sources
Other data sources provide additional data on public and private drinking water.
Eating Healthy Fish
Catching and eating fish in Missouri is a healthy activity and provides a good source of protein. However, contaminants that might be in the water can build up in fish tissue and bones. DHSS and the Missouri Department of Conservation regularly test fish across the state for contaminants. DHSS reviews the test results, issues warnings, and publishes fish consumption recommendations in the Missouri Fish Advisory.
Harmful Algal Blooms in Lakes, Ponds and Streams
Algal blooms can sometimes be found in lakes, ponds, and slow-moving streams in Missouri, especially during warmer weather. These blooms are caused by the growth of tiny organisms called algae or cyanobacteria (also known as blue-green algae) in the water. Not all blooms are harmful, but some can produce toxins (poisons) that can make you and your animals sick soon after being in the water. Drinking water or eating fish or shellfish from water with an algal bloom might also make you or your animals sick.
Health Effects
Bloom toxins can quickly harm your health. Symptoms include:
- Headache
- Throwing up
- Muscle or stomach pain
- Diarrhea
- Skin rash or blister
- Eye, ear, nose, mouth, or lung irritation
- Severe symptoms, like trouble breathing or moving
Health Tips
Many types of algal blooms are toxic and can look very different depending on the algae causing them. You cannot tell if they are toxic just by looking. It is best to avoid blooms in lakes, ponds, and streams.
If you were in water with a bloom:
- Remove wet clothing and jewelry
- Wash with soap and water
- Talk to a doctor if symptoms happen or get worse
- Call 911 right away if symptoms are severe
Protect Pets and Livestock
Algal blooms can harm your animals’ health too. Don’t let your pets or livestock:
- Get into the water with a bloom
- Drink or graze in or near water with a bloom
- Lick their fur after being in the water with a bloom
- Eat algae mats, dead animals or dead fish found near a bloom
If your animal was in water with a bloom:
- Wash them off right away with clean water
- Watch them for symptoms
- Call a veterinarian or poison control center if they show symptoms
Report a Bloom
If you see a possible algal bloom in a lake, pond, or stream, use this reporting form to notify the Missouri HAB Response Team. This team includes staff from several Missouri agencies who will investigate and respond to the bloom. You can see where blooms have been reported on the Harmful Algal Bloom Reports Map.
Additional Resources
- CDC Environmental Public Health Tracking - Drinking Water
- CDC - Harmful Algal Bloom (HAB) Associated Illness
- Missouri Department of Natural Resources - Water
- Missouri Department of Natural Resources - Harmful Algal Blooms
- EPA – Water Topics
- USGS - Water Data for the Nation
- USGS - Water Use in the United States
- USGS - Water Quality Criteria
Algal Blooms
