Rock County water test results surprise officials
CHECKING TEST RESULTS
To find out the E. coli test results of Rock County waterways.
JANESVILLE Your favorite swimming hole might be dirtier—or cleaner—than you think.
The results of stepped-up water quality testing on Rock County waterways have surprised even health officials.
“It’s been real interesting,” said Jeff Moore, an environmental health technician at the Rock County Health Department. “Places that you wouldn’t think were really good are really good, and places you think are great are not so great.”
Spring Brook in Palmer Park, for example, attracts kids and dogs alike, so officials were curious what test results would show.
The “fantastic-looking water” turned out to be not so great, Moore said.
Test results last year showed an E. coli count of 1,120 coliform forming units per 100 milliliter, a reading that would result in the immediate closure of a licensed beach.
The Spring Brook findings are a result of the Rock County Health Department’s increased water quality testing. In the last three years, the department more than quadrupled its testing sites, expanding from licensed beaches to most water bodies in Rock County.
“We knew the people were going in the water in other places, and really this is all about public health and awareness,” Moore said. “And so we wanted to see what the other water bodies even looked like.”
Sites are tested weekly, monthly or seasonally, depending on how much exposure residents have to the areas. Rock is one of three counties in the state that tries to test all its water bodies, Moore said.
“We’re really just trying to get an idea of what the baseline levels of bacteria are,” said Adam Elmer, a sanitarian at the department.
About the testing
The Wisconsin Department of Natural Resources uses E. coli as an indicator of contamination, Elmer said.
E. coli is a bacterium that can make humans and animals sick with symptoms such as vomiting and diarrhea. It is treatable with antibiotics.
Moore travels the county from May to September on “beach day” Mondays, collecting water samples and recording the water temperature and clarity. Samples are analyzed at the Wisconsin State Lab of Hygiene.
If the E. coli count hits 126 or more, “we start becoming concerned,” Moore said. “If it gets that same count for four straight tests, that basically would close down a licensed beach or make us do an advisory on a non-licensed water body.”
The same actions are taken if a single reading hits 1,000.
If people are taking kids swimming at an unlicensed beach, Moore recommends they check the county’s website for the tests results.
“You’ll at least have an idea of what the water quality is like,” he said.
He had always assumed Spring Brook’s water was great.
“I know different, now,” he said. “I don’t even let my dog go in Spring Brook.”
Factors in results
Moore admits he wouldn’t have guessed the Rock River in Traxler Park would be 10 times better than Spring Brook. Some of the lowest E. coli counts in the county are in the Rock River, Moore said.
“You wouldn’t think so,” he said. “Lake Koshkonong acts as a cleaning (agent). It cleans up the water tremendously.
“If anyone ever forced me to drink the water anywhere in the county, I’d go to Lake Koshkonong,” Moore said. “If I had to, just knowing the different counts all year round. … I’m sure plenty of skiers have.”
Counts are better when the water is colder, which it is by about 10 degrees this year compared to last year.
You might think water would be cleaner after a rain.
“Whenever it rains, it gets worse because all of the duck poop and all that stuff goes in,” Moore said.
E. coli counts spike after a rainfall and slowly decline, Elmer said.
Goose and duck poop, pet waste and agricultural runoff are the biggest causes of high test results, Moore said.
Most places with high counts are creeks and streams that run through rural areas with farming up to the waterway, Moore said. The Rock River has some a buffer, which might explain the better test results, he said.
Bacteria that are found in water are measured in CFUs, which are "colony forming units." They are given this name based on the laboratory testing methods used for counting bacteria such as coliform.
A water sample is shaken, and then a small amount of the water is plated on a bacterial growth media. The plate is then incubated in an oven. After about a day, any bacteria present will have multiplied, forming a small colony that appears as a dot. The colonies are counted, and this results in the bacterial "count" which is reported.