Rodent Complaints in Chicago: Where and When (2023–2026 311 Data)
By Marcus Ellery, Pest Control Editor · Updated September 2026 · Methodology
Chicago logged 43,083 rodent complaints in 2025, which was down 3.3% on 2024, and 30,478 so far in 2026 through September. The year peaks in July at about 12.29% of annual volume and bottoms out in December at 4.68%. The busiest wards over the three full years were Ward 13, Ward 45, Ward 38, Ward 30, Ward 11.
What Chicago counts
Every 311 service request of type "Rodent Baiting/Rat Complaint", which is a request for the city to bait a location for rats. Chicago flags service requests it later merges into an existing one; those duplicates are excluded here so a single location counted once.
Pulled from Chicago Data Portal — 311 Service Requests (dataset v6vf-nfxy) with the filter sr_type='Rodent Baiting/Rat Complaint' AND duplicate=false. 99.9% of records carry a ward. This is a different definition from the other cities we publish, so these counts should never be set against theirs.
Complaints by month, 2023 to 2026
September, October and November are shaded so you can see how the autumn months sit against the rest of the year in Chicago.
2023
Year total 47,116
2024
Year total 44,560
2025
Year total 43,083
2026 (through Sep)
Year total 30,478
One caveat about the Chicago data
Chicago is the awkward one geographically. The dataset carries a zip_code column, but it is blank on roughly 28% of rodent rows and the blanks are not spread evenly across the city, so a ZIP table built from it would quietly understate whole neighbourhoods. Ward is filled on almost every row, so ward is what we publish. That also means no per-square-mile column here: we have no cited source for ward land areas and we would rather leave a column out than estimate one. Chicago separately flags requests it merges into an existing one, and those duplicates are excluded so a single reported location counts once.
Reading the Chicago numbers
Chicago spreads its rodent complaints across 50 wards, and the load is not spread evenly. The busiest five carry 20% of the three-year total and the busiest ten carry 35%. Ward 13 alone logged 7,854 complaints, about 3.0 times the median ward in the city.
Across the year, July (12.29%), August (11.7%) and September (10.81%) are the three heaviest months, while December (4.68%), January (5.16%) and February (5.32%) are the three lightest. May through October alone accounts for roughly 64% of a Chicago year. Year to year the totals ran -5.4% into 2024, then -3.3% into 2025. 2026 stands at 30,478 through September.
Every month, in full
The raw counts behind the charts above, so you can check our arithmetic against Chicago Data Portal — 311 Service Requests yourself.
| Month | 2023 | 2024 | 2025 | 2026 | Avg share |
|---|---|---|---|---|---|
| January | 2,534 | 2,341 | 2,090 | 1,828 | 5.16% |
| February | 2,344 | 2,798 | 2,026 | 2,324 | 5.32% |
| March | 3,203 | 2,605 | 2,699 | 2,825 | 6.3% |
| April | 3,423 | 3,482 | 3,254 | 3,374 | 7.54% |
| May | 4,282 | 4,276 | 3,900 | 4,422 | 9.25% |
| June | 4,934 | 4,699 | 4,641 | 4,643 | 10.6% |
| July | 5,257 | 5,425 | 5,828 | 5,019 | 12.29% |
| August | 5,825 | 4,793 | 5,159 | 4,892 | 11.7% |
| September | 5,053 | 4,569 | 4,930 | 1,151 | 10.81% |
| October | 4,410 | 4,403 | 4,244 | — | 9.7% |
| November | 3,262 | 2,977 | 2,746 | — | 6.66% |
| December | 2,589 | 2,192 | 1,566 | — | 4.68% |
Average share is the mean of each full calendar year’s monthly share, so a heavy year cannot dominate the seasonal curve. The 2026 column is incomplete by design.
The 25 busiest wards in Chicago
Totals cover 2023 through 2025, the three full calendar years in the window. Chicago publishes ward rather than ZIP on these records, and we have no cited ward areas, so there is no per-square-mile column here.
| Rank | Ward | 2023–2025 total |
|---|---|---|
| 1 | Ward 13 | 7,854 |
| 2 | Ward 45 | 5,150 |
| 3 | Ward 38 | 4,901 |
| 4 | Ward 30 | 4,591 |
| 5 | Ward 11 | 4,463 |
| 6 | Ward 15 | 4,196 |
| 7 | Ward 32 | 4,106 |
| 8 | Ward 47 | 3,984 |
| 9 | Ward 36 | 3,907 |
| 10 | Ward 1 | 3,793 |
| 11 | Ward 26 | 3,774 |
| 12 | Ward 35 | 3,704 |
| 13 | Ward 39 | 3,525 |
| 14 | Ward 33 | 3,403 |
| 15 | Ward 23 | 3,132 |
| 16 | Ward 19 | 3,003 |
| 17 | Ward 40 | 2,988 |
| 18 | Ward 31 | 2,972 |
| 19 | Ward 16 | 2,939 |
| 20 | Ward 44 | 2,895 |
| 21 | Ward 43 | 2,866 |
| 22 | Ward 41 | 2,838 |
| 23 | Ward 17 | 2,796 |
| 24 | Ward 50 | 2,749 |
| 25 | Ward 49 | 2,681 |
50 wards recorded at least one complaint. Volume tracks reporting behaviour as well as rodent activity: a block that knows how to use 311 shows up more than an identical block that does not.
Freeze dates for Chicago
The nearest NOAA station publishing 1991–2020 first-freeze normals is CHICAGO NORTHERLY IS, 4.1 miles from the city point. One autumn in ten sees its first 32°F night by October 24; a typical year gets one around November 5; nine years in ten have had one by November 20. The station averages 96.5 nights a year below freezing.
We went into this expecting complaints to climb toward the first freeze. In Chicago they do not. Chicago complaints peak in July, and by November the month carries 4.15 percentage points less of the year than September did, with the typical first freeze still landing in November. We publish the gap rather than smoothing it. The likeliest reason is that a 311 rodent complaint is mostly an outdoor rat report, and outdoor rat activity runs highest in warm weather, while the autumn move indoors is house mouse behaviour that rarely becomes a city service request. Somebody with mice behind a kitchen cabinet calls an exterminator, not the city.
What removal costs if it is your house
National 2026 planning ranges from our estimator, not Chicago quotes.
| Inspection + trapping | $175 – $500 |
| Removal + exclusion (seal entry points) | $400 – $1,100 |
| Above + attic cleanup / decontamination | $700 – $2,000 |
Check a Chicago ZIP
Complaint total and rank inside Chicago, plus freeze dates for the nearest station.
Frequently asked questions
Which Chicago wards have the most rat complaints?
Over 2023 to 2025, the busiest wards were Ward 13 (7,854), Ward 45 (5,150), Ward 38 (4,901), Ward 30 (4,591), Ward 11 (4,463). Ward boundaries changed in the past decade, so treat ward totals as a guide to where calls come from rather than a fixed geography. A busy ward reflects how often people there call 311, which is not the same as how many rodents live there.
When do rodent complaints peak in Chicago?
July, which carries about 12.29% of the year's complaints against 4.68% in December, the quietest month. That is roughly 2.6 times the volume between the high and low month. Autumn is already past the peak: November carries 4.15 points less of the year than September does.
What exactly does Chicago count as a rodent complaint?
Every 311 service request of type "Rodent Baiting/Rat Complaint", which is a request for the city to bait a location for rats. Chicago flags service requests it later merges into an existing one; those duplicates are excluded here so a single location counted once. We pulled it from Chicago Data Portal — 311 Service Requests using the filter sr_type='Rodent Baiting/Rat Complaint' AND duplicate=false. Nearly every record carries a ward, so the ward table and the citywide totals agree closely.
Are rodent complaints rising in Chicago?
Between 2023 and 2025 they went down, by -8.6%. Year over year, 2025 was down 3.3% against 2024. Complaint counts move when a city promotes its 311 line or changes a category, so read the direction as a signal about reporting as much as about rodents.
Does the Chicago complaint peak match the first freeze?
No, and the mismatch is the interesting part. The typical first 32°F night at CHICAGO NORTHERLY IS lands in November, but Chicago complaints peak in July and are already falling by November. We checked this across all six cities we pull and the pattern held in every one of them, so we are not going to tell you 311 data proves a rodent season that starts at the first freeze. City 311 rodent complaints are dominated by outdoor rat activity, which runs highest in warm months. The autumn move indoors is mostly a house mouse story, and a mouse in your wall rarely generates a call to the city.
Sources
- Chicago Data Portal — 311 Service Requests — dataset v6vf-nfxy, filtered on
sr_type='Rodent Baiting/Rat Complaint' AND duplicate=false, extracted September 9, 2026. - NOAA NCEI U.S. Climate Normals 1991–2020 — station USC00111550, CHICAGO NORTHERLY IS.
- U.S. Census Bureau 2023 ZCTA gazetteer — ZIP land area used for the per-square-mile column.
- UC Statewide IPM Program — Pest Notes: Rats (Publication 74106) — rat behaviour and exclusion.
Getting a quote in Chicago
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PestCost is an independent cost-information site, not a pest-control company, and does not service Chicago. We may be compensated by licensed providers who receive your call or quote request. This never changes what you pay. Complaint counts describe what residents reported to Chicago, not a count of rodents.