Grimes does not drink the river. It pumps its own wells and treats them in town. Here is what that actually means for the water in your kitchen.
Grimes is genuinely different from its neighbors, and this is the one city page on our site where that difference is the headline instead of a footnote.
Grimes runs on a pair of registered public water supplies. Grimes Water Supply, PWSID IA7736011, is the distribution side, the pipes and meters that reach your house. It takes its treated water from CIWW (Grimes), PWSID IA7736015, the production side that owns the wells and the treatment plant. Grimes is one of the twelve founding members of Central Iowa Water Works, but it is the unusual one: it does not buy river-sourced treated water from Des Moines Water Works' plants. It makes its own, and the Iowa DNR classifies its source water type as Ground Water rather than Purchased Surface Water.
Grimes wells #100, #101 and #102 sit between 67 and 82 feet deep in the local alluvial aquifer. The Iowa DNR classifies alluvial aquifers as highly susceptible to surface contamination, because shallow groundwater in farm country is in conversation with whatever is on the ground above it.
Grimes #1 ASR, #201 and #202 reach 2,471 to 2,602 feet into the Cambrian-Ordovician formation, which most people around here call the Jordan aquifer. The DNR rates that one as low susceptibility. It is old, deep, protected water, and it is also mineral heavy, which is why it needs treatment before it reaches you.
Grimes has run a lime-softening plant since 2001. In 2021 it added a direct reverse osmosis plant rated at 3.57 million gallons a day across four RO trains, which treats Jordan aquifer water and then blends it back with the lime-softened stream. As of March 2026 that plant is being expanded from over 5 million gallons a day to 8.5 million. Central Iowa Water Works described the deep source this way to WHO 13: "The Jordan Aquifer is a low-nitrate source of water with undetectable levels of nitrate. There is no nitrate coming out of this plant." That is a real advantage over the river-fed side of the metro, and we are not going to pretend otherwise.
Grimes publishes its own consumer confidence reports rather than appearing in the regional Des Moines Water Works report. Every number below comes from the city's 2024 and 2025 reports.
ppb lead at the 90th percentile in Grimes, with the highest single home at 1 ppb. That is a clean result by any standard.
Grimes 2024 Water Quality Report ↗ppm running annual average disinfectant residual through the end of 2024, ranging to 3.8, against a maximum of 4.0. High for this metro.
Grimes 2024 Water Quality Report ↗nitrate, trihalomethane or haloacetic acid results published in either of the two most recent Grimes reports. Not a pass. Just not measured there.
Grimes 2025 Water Quality Report ↗| Grimes water system | Result | Range | Limit |
|---|---|---|---|
| Disinfectant residual, annual average (2024) | 3.0 ppm | 2.1 to 3.8 | 4.0 ppm |
| Lead, 90th percentile (2023 sampling) | 0.00 ppb | ND to 1 ppb | 15 ppb action level |
| Copper, 90th percentile (2023 sampling) | 0.0198 ppm | 0.00128 to 0.0312 | 1.3 ppm action level |
| Nitrite as N (2024) | 0.215 ppm | ND to 0.215 | 1 ppm |
| Arsenic (July 2023) | 1.10 ppb | single sample | 10 ppb |
| Barium (July 2023) | 0.00818 ppm | single sample | 2 ppm |
| Gross alpha (March 2025) | 0.8 pCi/L | single sample | 15 pCi/L |
| Fluoride (June 2025) | 0.15 ppm | single sample | 4 ppm |
| Dalapon, an herbicide (August 2025) | 0.60 ppb | single sample | 200 ppb |
| Sodium (July 2023) | 14.5 ppm | single sample | no federal limit |
Grimes water met every federal standard in both of those reports. No violations, no exceedances, nothing close to a limit. Arsenic came in around a ninth of what is allowed, barium at a fraction of a percent of its limit, and gross alpha radioactivity at about a twentieth. If you came here expecting us to tell you the city water is dangerous, we are not going to, because the numbers do not say that. Four things are still worth understanding.
One, the disinfectant residual is high for this metro. A running annual average of 3.0 ppm with samples reaching 3.8 is legal, the ceiling is 4.0. It is also roughly three times what the river-sourced CIWW systems reported in the same period, where Des Moines averaged 1.20 ppm and Urbandale 0.80. That Grimes figure covers 2024, when the city was still on chloramine. Grimes converted to free chlorine at the end of April 2025 to line up with the rest of the Central Iowa Water Works network, which is why some neighbors noticed the taste change that spring. Disinfectant is not a health villain, it is doing a necessary job, but it is the single most common reason a Grimes homeowner tells us their water tastes like a swimming pool.
Two, that nitrite result is not nitrate. Grimes reported 0.215 ppm of nitrite as N against a limit of 1 ppm. Nitrite and nitrate are separate compounds with separate limits, and we watch people confuse them constantly. Neither of Grimes' recent reports publishes a nitrate laboratory figure at all, so anyone quoting you a Grimes nitrate number is reading the wrong row or borrowing it from another city.
Three, there are real gaps in what gets published here. Grimes' reports contain no nitrate result, no trihalomethane result and no haloacetic acid result. The regional Des Moines Water Works report publishes all three for cities like Urbandale, Clive and Ankeny, but those figures describe river water treated at other plants and they do not transfer to Grimes. We are not going to borrow them. An absent number is not a clean number, it just means nobody handed you one, and a disinfectant residual that high is exactly the condition where you would want the byproduct figure to look at.
Four, lead never comes from the plant. Grimes' 90th percentile lead was 0.00 ppb and the worst house tested at 1 ppb, which is genuinely excellent. But lead is a plumbing story, not a utility story. It enters between the water main and your faucet, from solder, fixtures and service lines specific to one address. A citywide 90th percentile tells you about the city. It does not tell you about your kitchen.
Better source water did not buy Grimes an exemption, and anyone telling you otherwise is selling something.
Central Iowa Water Works issued the first Stage III mandatory lawn watering ban in the region's history in June 2025, and did it again on June 8, 2026, saying the regional system was "operating at the limits of its available treatment resources." The trigger was nitrate loading in the Raccoon and Des Moines rivers, which ran past 15 mg/L in June 2025 against a 10 mg/L federal limit.
CIWW Stage III, Jun 2026 ↗CIWW listed Grimes among the member communities bound by both bans. Grimes is a founding member sitting on an interconnected regional network, so network-wide conservation applies to it even though its own wells are not the river. That is a demand and capacity story, not a Grimes water quality story. Be skeptical of anyone who tells you Grimes had a nitrate emergency. It did not.
Iowa Public Radio, Jun 2026 ↗Iowa has the second-highest cancer incidence rate in the country, and researchers have connected long-term nitrate exposure in drinking water to several cancers. That is why nitrate dominates the water conversation everywhere else in this metro. In Grimes it is the least of your concerns, and we would rather say that plainly than manufacture a scare to close a sale. What is left in Grimes is the ordinary stuff: a disinfectant residual high enough to taste, minerals carried up from deep Jordan aquifer water, a trace herbicide showing up in the shallow wells, byproduct figures nobody publishes, and whatever your own plumbing contributes on the last twenty feet of the trip. Investigate Midwest, Mar 2026 ↗
Grimes counted 17,809 residents in its own 2025 special census, up 15.7% from 15,392 at the 2020 Census. Five years is a short window for that kind of jump, and it explains why the city is spending money expanding its reverse osmosis plant rather than coasting on it.
Housing units went from 5,708 in 2020 to 7,578 in 2025, a 32.7% increase, growing faster than the population itself. Practically, that means most Grimes kitchens we work in are recent construction: modern shutoffs, clean cabinet runs, and almost always granite or quartz countertops. We drill natural stone in house, so a stone top is not a reason to delay or a reason to pay a second trade.
Roughly 70.9% of Grimes households own their home, with a median home value near $304,700 in 2024 Census-derived estimates. An under-sink RO system is a permanent improvement to the house, which is an easier decision when you are the one staying in it.
The city's RO plant treats a share of the supply before it leaves the plant. Yours treats what is actually in the pipe when it reaches your glass.
We install the iSpring RCC7AK 7-stage system under your kitchen sink with its own dedicated faucet. Installation takes one to two hours. Pricing is $699, $849 or $1,099 fully installed depending on configuration, with no separate plumber charge.
Prime Flow Filtration does point-of-use drinking water only. We do not sell whole-house systems, softeners or well treatment. Given how good Grimes' published numbers are, there is a real chance we test your tap and tell you that you are fine. We would rather say that than sell you something you do not need.
Free in-home water test, no obligation. We test your actual kitchen tap, show you the numbers, and tell you honestly whether a system is worth it.