Osceola Water Works Did Not Meet Treatment Requirements

Our water system rexcently violated two drinking water standards. Although this was not an emergency, as our customers, you have a right to know what happened, what you should do, and what we did to correct this situation.

We routinely monitor your water for turbidity (cloudiness). this tells us whether we are effectively filtering the water supply. Water samples for August shjowed that 37% of turbiditiy measurements were over 0.3 turbidity units – the standard is that no more than 5% of samples may exceed 0.3 turbidity units per month. The turbidity levels are relatively low. However, their persistence is a concern. Normal turbidity levels at our plant are below 0.3 turbidity units. Furthermore, a water sample taked 8/10/2020 showed levels of 1.9 turbidity units. This was avove the standard of 1 turbidity unit. Because of these high levels of turbidity, there is an increased chance that the water may contain disease-causing organisms.

What should I do?

  • You do not need to boil your water or take other actions. We do not know of any contamination, and none of our testing has shown disease-causing organisms in the drinking water.
  • People with severely compromised immune systems, infants, and some elderly may be at increased risk. These people should seek advice about drinking water from their health care providers. General guidelines on ways to lessen the risk of infection by midrobes are available from EPA’s Sage Drinking Water Hotline at 1(800)426-4791.

What does this mean?

Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for midrobial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites which can cause symptoms such as nausea, cramps, diarrhea, and associated headaches. These are not caused only by organisms in drinking water. If you experience any of these symptoms and they persist, you may want to seek medical advice.

What happened? What was done?

A problem occurred with the treatment process at the water lant due to a large blue green algae bloom that occurred in West Lake. West Lake is where the City of Osceola obtains source water for treatment and distribution of drinking water. Due to the algae bloom, increased turbidity levels were seen in each individual filter. In response to the algae bloom, Osceola Water Works worked with its chemeical supplier and the Iowa DNR to troubleshoot the event. Despite efforts, which include changing intake levels in West Lake, chemical feed additions, and adjustments to chemical doses, the exceedance of the combined filter effluent turbidity occurred. Levels reached 1.9 NTU on August 10, 2020. It appears that the source of the turbidity increase was also due to an increase of manganese in the source water. Osceola Water Works has adjusted its treatment processes and added sodium permanganate to the treatment process to help with the manganese and algal issue in West lake. Osceola Water Works returned to compliance on Wednesday, August 19th, 2020.

For more information, please contact Osceola Water Works at 641-342-1435 or email

This notice is being sent to you by Osceola Water Works.
PWSID#: 2038038 Date distributed: 9/1/2020