Part 1 · Start here
Two things are true at once
Among the best-treated in the country
Public water utilities test constantly and almost always meet every federal health standard. Even during the record nitrate of 2025 and 2026, Des Moines–area tap water never broke the limit. The systems that do fail are mostly tiny: every Iowa system that broke the nitrate limit in 2025 — 13 of them — served just 2,479 people combined.
Among the most polluted in the country
About half of Iowa’s assessed rivers and lakes fail a health or use standard — 577 water bodies are on the state’s official cleanup list. This spring, the rivers that supply Des Moines climbed to near-record nitrate, well above the level that’s legal to drink.
How can both be true? Water plants stand between the rivers and your faucet. They clean some of the most nitrate-heavy water in America until it’s legal to drink — and the cost lands on your water bill. In 2025 and again in 2026, the rivers got so bad that 600,000 Iowans were told to stop watering their lawns so the cleaning could keep up. That had never happened before.
Part 2 · Your water
Which water do you drink?
City or town water
About 9 in 10 Iowans
- Your utility must test regularly and meet federal limits. It almost always does.
- Even during the 2025–26 nitrate crises, Des Moines–area tap water stayed under the limit.
- The systems that do fail are mostly small towns, churches, and campgrounds that can’t afford treatment.
What to do: your utility publishes a water-quality report every year. Find yours at epa.gov/ccr.
Private well
Roughly 230,000–290,000 Iowans
- No law requires anyone to test your well, and no legal limits apply to it.
- Of Iowa wells that were tested, about 1 in 8 had nitrate over the legal limit, and more than 40% tested positive for bacteria at least once.
- Untested wells are likely worse, not better. Arsenic and manganese also occur naturally in some Iowa groundwater.
What to do: testing is free or low-cost through your county health department (Iowa’s Private Well Grants Program). Test before mixing formula for a baby.
Part 3 · The rivers
How dirty are the rivers, exactly?
Sensors measure nitrate in Iowa’s rivers around the clock. Here are the near-record peaks the two rivers that supply Des Moines reached on June 16, 2025. Anything past the dashed line has more nitrate than tap water is legally allowed to have — water plants downstream must remove the difference before it reaches you.
(June 16, 2025 peak)
(June 16, 2025 peak)
A river over the line isn’t illegal — the limit applies at your tap. But the Raccoon River, Des Moines’s main source, has spent much of 2025 and 2026 above the limit, and it now spikes even in winter, which used to be unheard of. Rivers change daily — see today’s live readings.
Part 4 · The lakes
Can the kids swim in it?
It isn’t just about drinking. The same runoff that loads the rivers feeds fecal bacteria and toxic algae in the lakes where Iowans swim.
- The Iowa DNR tests 41 state-park beaches every week from the week before Memorial Day through Labor Day, and posts a “Swimming is Not Recommended” sign when bacteria or toxin levels cross the safe line. Advisories are updated on Fridays.
- Two things trigger the sign: E. coli (bacteria that mean the water has met fecal matter) and microcystin, a liver toxin from the blue-green algae blooms that nutrient runoff feeds. High exposure can cause stomach illness, rashes, and — for dogs — can be deadly.
- What to do: check the DNR beach list before you load the car. It’s the single most useful link on this page in summer.
Part 5 · The why
Why is this happening? Four steps.
We farm almost everything
Most of Iowa is farmland, and the state raises about 25 million hogs — more than any other state. That means a lot of fertilizer and manure carrying nitrogen.
Crops don’t take all of it
On average, Iowa fields get more nitrogen than the crops can use. Rain turns the leftover into nitrate and washes it downward — the same nitrogen a farm paid for, leaving the field.
Buried pipes rush it to the rivers
Much of Iowa’s cropland drains through buried “tile” pipes that move water — and nitrate — to streams in hours instead of decades. The result: Iowa is 4.5% of the Mississippi basin’s land but sends about 29% of the nitrate that reaches the Gulf of Mexico.
Water plants clean it up — for a price
Des Moines runs one of the world’s largest nitrate-removal facilities. Running it costs roughly $10,000 a day — up to about $16,000 at full tilt, paid by customers on their water bills.
One more piece: farm runoff is exempt from the Clean Water Act’s permit system — cities and factories face enforceable limits, farm fields don’t. Iowa’s response, since 2013, has been voluntary.
Part 6 · Health
What does this do to people?
This is the most argued-about part, so here it is carefully — what’s proven, and what’s only a link.
Babies
- Too much nitrate can keep a baby’s blood from carrying oxygen — “blue baby syndrome.” That’s why the legal limit exists. It’s rare today because utilities treat for it.
- A 2025 study of 357,741 Iowa births linked nitrate in early pregnancy to more early births and smaller babies — at half the legal limit, and below. This is a statistical link, not proof.
- If you’re pregnant and on a well: test before drinking it or mixing formula.
Cancer
- Iowa has the #2 cancer rate in the country, and it’s one of only two states where the rate is rising.
- Scientists list nitrate — with radon, pesticides, and PFAS — as a suspected contributor. But the biggest known drivers are still tobacco, alcohol, and obesity. A link is not proof, and no one yet knows how much, if any, is from water.
- The hopeful part: even as diagnoses rise, cancer death rates in Iowa are falling, thanks to better detection and treatment.
Other contaminants worth knowing: PFAS (“forever chemicals”) were found in about half of sampled public supplies, most below the newest federal limits; arsenic and manganese occur naturally in some wells — another reason to test a private well.
Part 7 · Monitoring
Are we even watching the water?
Everything on this page depends on two things: sensors that watch the water constantly, and studies that connect the water to health. Iowa has both — but neither is secure.
- Sensors watch in real time. About 60 university-run sensors (University of Iowa), plus federal USGS gauges, read river nitrate every ten minutes and publish it to the public Iowa Water Quality Information System. That’s how we know a river is over the limit today, not months later — the readings in Part 3 exist because of them.
- But the network isn’t secure. In May 2026 the state again declined to directly fund the university sensor network ($300,000), which is now surviving on county and private money. Fewer sensors means finding out later — or not at all.
- Private wells have no watchers at all. No one is required to monitor them, so most are simply never tested.
Part 8 · How we got here
The rules that shaped today’s water
- The exemption. Factories and city sewer plants need permits with enforceable pollution limits. Farm runoff does not — so most of the nitrogen in Iowa’s streams has no legal cap.
- The lawsuit. When Des Moines Water Works sued upstream drainage districts in 2015 to help pay for nitrate removal, the Iowa Supreme Court ruled in 2017 that drainage districts have century-old immunity, and the case was dismissed.
- The voluntary plan. Iowa’s Nutrient Reduction Strategy (2013) sets a goal of cutting nitrogen and phosphorus 45% — but taking part is voluntary.
- Oversight gaps. In 2012 the EPA found Iowa’s factory-farm permitting and enforcement fell short of federal minimums. An advocacy analysis (Food & Water Watch) found Iowa factory farms paid under $750,000 for 179 reported manure spills over a decade, with thousands of operations running without Clean Water Act permits.
- The fund voters approved. In 2010, 63% of Iowa voters approved a constitutional trust fund for clean water and conservation. Fifteen years later it has never been funded, because the small sales-tax increase that fills it hasn’t happened.
Part 9 · What works
What would actually get us better water?
The good news up front: cleaner water and strong harvests are not opposites. The fixes are known, measured, and mostly already in use somewhere in Iowa.
- Use fertilizer more precisely. Iowa already applies more nitrogen than crops need on average. Dialing back to the agronomic sweet spot would cut nitrate loss about 9% while saving farmers money — same harvest, less runoff.
- Plant cover crops. A winter rye cover crop cuts the nitrate leaving a field by roughly a third, and it’s the single highest-impact practice statewide — with little yield effect when well managed.
- Put buffers between fields and water. Riparian buffer strips remove around 90% of the nitrate in water passing through them; edge-of-field “saturated buffers” and bioreactors on tile-drained land cut 40–55%.
- Restore wetlands to filter runoff before it reaches streams.
- Hold large livestock operations and manure to enforceable standards, the way factories already are — so the rules match the size of the source.
Iowans already agree. This isn’t a partisan fight: 79% of Iowans — including 69% of Republicans — support restoring water-monitoring funding, and the 2010 clean-water amendment passed with 63% of the vote.
Honest about scale: doing enough of this to hit the 45% goal is a big lift — on the order of $750 million a year. But that number is known and bounded, not a mystery. The tools work; the question is how fast we use them.
Part 10 · Iowa vs. the nation
How does Iowa compare?
Iowa ranks among the worst states for impaired waters — about half of the rivers and lakes the state assesses don’t meet standards.
With just 4.5% of the Mississippi basin’s land, Iowa sends about 29% of the nitrate reaching the Gulf of Mexico — the single largest state share, feeding the Gulf “dead zone.”
Iowa is 2nd in the nation for new cancers and one of only two states where the rate is rising — though how much water contributes is still an open question.
Iowa’s real-time water monitoring is among the best in the country. We can see the problem clearly — the task is to keep funding the sensors and act on what they show.
Part 11 · The debate
Both sides, honestly
“The water is safe, and things are improving”
- Tap water met every federal standard even during the 2025–26 crises.
- More farmers are adopting cover crops and edge-of-field practices every year.
- The state has committed new water-quality funding and cost-share for farmers.
“The problem is real, and growing”
- River nitrate set records and triggered the first-ever watering bans — from pollution, not drought.
- Drinking-water nitrate violations doubled in a year (14 → 36), all at small rural systems.
- After more than a decade, the voluntary plan is far short of its 45% goal.
Both columns are built from public data. The point of this guide isn’t to pick a side — it’s to make sure every Iowan can see the same facts.
Take five minutes
What you can do today
On a private well? Get it tested — free or low-cost — through your county health department. Do it before mixing baby formula.
On city water? Read your utility’s yearly water-quality report at epa.gov/ccr.
Headed to the lake? Check the DNR beach advisories — updated every Friday in summer.
Curious about your river? Watch live nitrate readings on the Iowa Water Quality Information System.