LITTLE BIT, AND WE’LL CHECK BACK IN WITH YOU SOON. RIGHT NOW, MUCH OF CENTRAL IOWA IS STILL UNDER A LAWN WATERING BAN. IT’S DUE TO HIGH NITRATE LEVELS IN OUR WATER SOURCES. YOU’RE TAKING A LOOK AT ALL THE CITIES AND COMMUNITIES THAT THIS BAN IMPACTS. LAST WEEK, OFFICIALS IN GRIMES SAY THEY’RE NOT TAKING PART IN THE BAN. MEANTIME, CIW OFFICIALS STRESS DRINKING YOUR TAP WATER IS STILL SAFE TO DO. BUT OVER THE WEEKEND, WE HEARD FROM A LOT OF YOU WHO PERFORMED AT HOME NITRATE TESTS. THAT’S RIGHT. AND THE RESULTS ALL SHOW LEVELS WAY ABOVE. WHAT WATER WORKS IS REPORTING. THAT’S WHY WE SENT vlog BEAU BOWMAN ON A MISSION TO FIGURE OUT THE ACCURACY OF THE AT HOME TEST STRIPS AND WHAT THEIR RESULTS ACTUALLY MEAN. DES MOINES WATER WORKS IS REPORTING THAT THE NITRATE LEVELS IN THEIR TREATED WATER ARE BETWEEN EIGHT AND 8.25MG/L, WHICH MEANS IT’S STILL SAFE. THE EPA SAYS IT’S NOT DANGEROUS UNTIL THAT NUMBER GETS TO TEN. BUT OVER THE WEEKEND, VIEWERS SENT vlog THE RESULTS OF THEIR OWN TEST PERFORMED AT HOME. WE’VE ALSO SEEN SEVERAL ON SOCIAL MEDIA, AND THEY SHOW NITRATE LEVELS AT MORE THAN 40 PARTS PER MILLION. EXTREMELY HIGH. TODAY WE DECIDED TO DO A LITTLE EXPERIMENT OF OUR OWN. I LIVE IN JOHNSTON, SO WE’LL BE USING MY HOUSE. WE’RE A PART OF CENTRAL IOWA WATER WORKS, AND WE’RE GOING TO SEE HOW THE WATER STACKS UP. WE’LL BE DOING TWO TESTS, ONE FROM THE TAP AND ONE FROM THE FILTER ON THE REFRIGERATOR. YOU CAN BUY THESE LITTLE STRIPS AT JUST ABOUT ANY BIG RETAILER. WE GOT THESE AT WALMART FOR 15 BUCKS. AND ALL YOU DO IS DIP THEM AND THEN WAIT 30S THE RESULTS ARE IN. AND I GOT A SIMILAR READING TO WHAT OUR VIEWERS DID BETWEEN 40 AND 50 PARTS PER MILLION ON THE TAP WATER, NEARLY ZERO ON THE FILTER. BUT EXPERTS SAY THESE TESTS ARE NOT RELIABLE. SO ONE OF THE THINGS YOU HAVE TO BE CAREFUL ABOUT IS WHEN USING THESE AT HOME KITS, YOU KNOW, WHAT DOES IT ACTUALLY REPORTING IN? AND DAVID SCHWARTZ IS A FACULTY RESEARCH ENGINEER IN HYDRO SCIENCE AT THE UNIVERSITY OF IOWA. HE SAYS THE STRIPS ARE TESTING FOR THE ENTIRE NITRATE ION, WHEREAS CENTRAL IOWA WATER WORKS AND OTHER WATER UTILITIES ARE ONLY LOOKING AT THE NITRATE NITROGEN TO DETERMINE WATER QUALITY. 10MG/L, AS NITROGEN IS ACTUALLY CLOSER TO ABOUT LIKE 4548. WHEN YOU THINK OF IT IN TERMS OF THE WHOLE, LIKE IRON OR WHAT WE’D CALL THE MOLECULE OF NITRATE, AND A READING ON A STRIP OF 40 TO 50 PARTS PER MILLION CONVERTS CLOSELY TO THE LEVELS. WATER WORKS IS REPORTING. SCHWARTZ ADDS, THAT THE TECHNOLOGY USED AT WATER WORKS TREATMENT CENTERS IS MUCH MORE ACCURATE THAN A TEST STRIP, AND THEY’RE GOING TO END UP ALWAYS BEING BETTER AND MORE RELIABLE
Central Iowa water quality experts say at-home nitrate test kits are unreliable
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Updated: 5:48 PM CDT Jun 23, 2025
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Much of central Iowa remains under a lawn watering ban due to elevated nitrate levels in water sources. While officials assure residents that tap water is safe to drink, discrepancies between at-home nitrate test results and official reports have sparked concern.Des Moines Water Works reports nitrate levels in treated water between 8 and 8.24 milligrams per liter, which is below the Environmental Protection Agency's safety threshold of 10 mg/L. However, over the weekend, many vlog viewers shared results from at-home nitrate tests, many of which showed levels exceeding 40 parts per million. These findings have also circulated widely on social media. Experts, however, caution against relying on these at-home tests. David Cwiertny, a professor of civil environmental engineering and chemistry at the University of Iowa, explained that the strips measure the entire nitrate ion, while water utilities like Central Iowa Water Works focus on nitrate-nitrogen to assess water quality. "10 mg/L nitrogen is actually closer to about 45-48 when you think of it as a whole ion, what we call the molecule of nitrate," Cwiertny said.This means that the at-home test results align more closely with the levels reported by Water Works when properly converted.Cwiertny emphasized the superior accuracy of the technology used at water treatment facilities."They're going to end up always being better and more reliable than with what we may see with these test strips," he said.While the lawn watering ban remains in effect, officials continue to stress that the tap water is safe for consumption, urging residents to trust the data provided by Central Iowa Water Works.Recent coverage of central Iowa water issuesCentral Iowa officials ban lawn watering to avoid potential 'water crisis'What are nitrates in drinking water and why Iowa officials are watching closelyLIST: Which Iowans are included in the ban on lawn watering?Des Moines shuts down spraygrounds as central Iowa cities work to conserve waterClive residents respond to lawn watering ban amid high nitrate levelsCentral Iowa landscaping businesses adapt to lawn watering banLawn watering ban still in place for more than 600,000 central Iowans; water usage drops by 30%Des Moines Water Works CEO links nitrate issue to farm fertilizers Communities can reopen splash pads and spraygrounds, Central Iowa Water Works says Get the Facts: How much water do West Des Moines data centers actually use?Splash pads turn back on one week later after new guidance from CIWWCentral Iowa water officials squash rumors that drinking water is unsafe
DES MOINES, Iowa — Much of central Iowa remains under a lawn watering ban due to elevated nitrate levels in water sources. While officials assure residents that tap water is safe to drink, discrepancies between at-home nitrate test results and official reports have sparked concern.
Des Moines Water Works reports nitrate levels in treated water between 8 and 8.24 milligrams per liter, which is below the Environmental Protection Agency's safety threshold of 10 mg/L.
However, over the weekend, many vlog viewers shared results from at-home nitrate tests, many of which showed levels exceeding 40 parts per million. These findings have also circulated widely on social media.
Experts, however, caution against relying on these at-home tests. David Cwiertny, a professor of civil environmental engineering and chemistry at the University of Iowa, explained that the strips measure the entire nitrate ion, while water utilities like Central Iowa Water Works focus on nitrate-nitrogen to assess water quality.
"10 mg/L nitrogen is actually closer to about 45-48 [ppm] when you think of it as a whole ion, what we call the molecule of nitrate," Cwiertny said.
This means that the at-home test results align more closely with the levels reported by Water Works when properly converted.
Cwiertny emphasized the superior accuracy of the technology used at water treatment facilities.
"They're going to end up always being better and more reliable than with what we may see with these test strips," he said.
While the lawn watering ban remains in effect, officials continue to stress that the tap water is safe for consumption, urging residents to trust the data provided by Central Iowa Water Works.
Recent coverage of central Iowa water issues
