01The verdict: is Stillman Valley water safe?
Stillman Valley's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (94.3/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,200 residents using groundwater (wells).
1 unresolved violation on record
EPA records show an open compliance item for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 1.5 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓A flood-prone service area
5 federal disaster declarations on record. After severe weather, watch for boil-water advisories.
See the risk factors ↓Stillman Valley's drinking water received a grade of A (94.3 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 1,200 residents using groundwater.
Lead levels were measured at 1.5 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 9 violations on record, including 0 health-based violations. 1 remains unresolved.
Stillman Valley ranks #25 out of 882 cities in Illinois for water quality, placing it one of the best in the state. Stillman Valley relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff. As a small community water system, Stillman Valley may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Stillman Valley's water
Every contaminant flagged in Stillman Valley, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 1.5 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in Illinois
Cities ranked by compounds detected Cu Copper in Illinois
Cities ranked by 90th-percentile copper
03Stillman Valley's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 9 violations on record, including 0 health-based violations. 1 remains unresolved.
All ten of the last ten years were clean — no EPA violations recorded for Stillman Valley.
▼ Down 0 ppb since 1993. Latest reading: 0 ppb (2025) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Stillman Valley's water comes from
Stillman Valley's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under local government ownership.
1,200 people
Residents served across Stillman Valley's service area.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals. Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds. The system is operated by local government ownership and serves approximately 1,200 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| STILLMAN VALLEY | IL1410550 | 1,200 | Groundwater |
Water bodies near Stillman Valley
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on Stillman Valley's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Industrial discharge
5 facilities within 10 miles reported 0 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.
Flood & storm history
5 federal disaster declarations on record for Ogle County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Superfund proximity
3 National Priorities List sites within 10 miles. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
06How Stillman Valley compares
Scores for nearby Illinois cities on one line, with the average marked.
dashed line = Illinois average (55/100)
Stillman Valley scores 94.3/100 — above the Illinois average of 55/100. It outscores 10 of 10 nearby cities. Full Illinois rankings →
35.2 / 100DAurora, IL
45.5 / 100FJoliet, IL
38.5 / 100BNaperville, IL
81.2 / 100FRockford, IL
38.4 / 100FKankakee, IL
42.6 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Stillman Valley's water — not generic advice.
A basic carbon filter still helps
Stillman Valley's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Stillman Valley alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Stillman Valley, IL tap water safe to drink?
Stillman Valley's water quality earned a grade of A (94.3/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #25 out of 882 cities tested in Illinois.
What contaminants are in Stillman Valley's water?
Lead was measured at 1.5 ppb (90th percentile). 9 violations are on record.
How is Stillman Valley's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Stillman Valley?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Stillman Valley's water come from?
Stillman Valley's water is sourced from Groundwater. The city has 1 water system serving approximately 1,200 residents.
Is Stillman Valley's groundwater at risk of contamination?
Stillman Valley uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 9 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Stillman Valley's water compare to other cities?
Stillman Valley ranks #25 out of 882 cities in Illinois (better than 97% of state cities) and #546 out of 15382 cities nationally (97th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Stillman Valley's small water system affect quality?
Stillman Valley's system serves approximately 1,200 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 9 violations on record.