Lead (Pb) Information

The Iowa DNR is responsible for implementing the Safe Drinking Water Act in Iowa.  The U.S. Environmental Protection Agency has requested that information related to each state’s public water supply systems and the implementation of the federal Lead and Copper Rule be available on the state agency’s website.  Listed below are documents with information pertaining to their request.

EPA’s Request Letter of February 29, 2016 and the attachment (Clarification of Sampling Procedures)

IDNR’s Response Letter of March 28, 2016

Several of the systems have information posted on their websites related to the location of lead service lines, results of lead testing, and other information.  In addition, the annual Consumer Confidence Report that is required of every community public water supply system is published by July 1st each year.  That report contains specific information regarding the lead levels from the most recent testing by the system, the 90th percentile action level, and an informational paragraph on how a person can avoid lead exposure.  If you have specific concerns, contact your public water system.

The analytical data for all systems required to meet the Lead and Copper Rule is also available from Drinking Water Watch.

The Iowa Public Drinking Water Program Annual Compliance Reports are available by calendar year.  The lead and copper action level requirements are described in the report, along with all action level exceedances and all major monitoring violations that were incurred during that year.

The Lead and Copper Sampling Plan template is available in the middle section on the Forms webpage.

The various Lead Consumer Notice templates are available in the bottom section on the Forms webpage.  


Lead Information: Schools & Child Daycares

There is a keen interest now about lead levels in drinking water, particularly in schools and child daycares.  This document describes the two separate federal programs for the testing of lead in drinking water, which have different purposes and requirements.

Additional information can be found on these websites: EPA’s Office of Groundwater and Drinking Water Website for Schools and Daycares and the Iowa Department of Health's Lead Poisoning Prevention Program Website.

Cyanotoxin Information

Cyanobacteria (blue-green algae) are photosynthetic bacteria that share some properties with algae and are found naturally in all surface waters, both freshwater and marine.  Cyanobacteria have been around for over a billion years, and helped form the Earth’s atmosphere by producing oxygen from photosynthesis.

There are several types of cyanobacteria, some of which can generate one or more chemicals that are toxic to humans and animals.  When conditions are favorable, cyanobacteria can rapidly multiply and cause algal blooms.  Sometimes the cyanobacteria produce toxins that can be harmful.  Cyanotoxins, specifically microcystin, were the cause of the “Do Not Use” water event in Toledo, Ohio, for several days in August 2014. 

Toxin-producing strains in the Midwest are typically seen in early summer and late summer.  Under conditions that are not fully understood but involve light and nutrients, some types of cyanobacteria can form toxins.  Both toxic and non-toxic varieties of the most common cyanobacteria can be present at the same time.  It is impossible to tell if a species is producing toxin or not just by looking at it.

Factors that affect cyanobacterial bloom formation and persistence include:

  • Light intensity and total sunlight duration: stronger light and longer duration
  • Nutrient availability (both nitrogen and phosphorus)
  • Water temperature:  warmer temperatures, in the range of 60°F – 80°F

The toxins from cyanobacteria can be harmful to the environment, animals, and human health.  In humans, symptoms include skin rashes, nausea, diarrhea, fatigue, and can cause toxic effects to the nervous system, liver, and kidneys.  In addition, decay of the algae bloom consumes oxygen that can cause die-off of aquatic plants and animals.  Exposures from recreational water include direct contact, ingestion, and inhalation from aerosol droplets.  Effects can be seen within minutes to days after exposure, depending upon toxin type and concentration.  Animals, particularly dogs, can have a more rapid and greater exposure from licking algae off of their fur.

In 2015, EPA issued 10-day health advisory levels for two cyanotoxins in finished (treated) drinking water:  microcystin and cylindrospermopsin.  These are non-regulatory levels that public water supply systems which voluntarily monitor for the two cyanotoxins can use to interpret the results.  In July 2016, many of the surface water and influenced groundwater public water supply systems in Iowa participated in a year-long study monitoring the microcystin level in the raw water each week.  If microcystin was detected, the system followed with finished (treated) water sampling.  The flowchart was used to determine the steps required if microcystin was detected.  The same concept was used to develop a flow chart for cylindrospermopsin.

Public Notice examples for cylindrospermopsin and microcystin are listed on the DNR's Public Notice webpage.

In the 2016-2017 Iowa study, there was no detection of microcystin in the finished (treated) drinking water at any of the participating public water supply systems.  A report of that study will soon be available and posted here.

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