01The verdict: is Custer City water safe?
Custer City's drinking water has significant quality concerns based on EPA testing data. With a grade of B (78.6/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 1,353 residents using groundwater (wells).
4 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Top half in Oklahoma
Custer City ranks #87 of 357 graded Oklahoma cities.
See the comparison ↓3 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Custer City's drinking water received a grade of B (78.6 out of 100), indicating good water quality. The city's 2 water systems serve approximately 1,353 residents using groundwater.
Lead levels were measured at 6.5 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 7 violations on record, including 2 health-based violations. 4 remain unresolved.
Custer City ranks #87 out of 357 cities in Oklahoma for water quality, placing it above average in the state. Custer City 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. While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection. As a small community water system, Custer City may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Custer City's water
Every contaminant flagged in Custer City, 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. | 6.5 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in Oklahoma
Cities ranked by compounds detected Cu Copper in Oklahoma
Cities ranked by 90th-percentile copper
03Custer City'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 7 violations on record, including 2 health-based violations. 4 remain unresolved.
7 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 0 ppb since 1993. Latest reading: 0 ppb (2023) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Custer City's water comes from
Custer City'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.
2 systems
2 water systems, operated under local government ownership.
1,353 people
Residents served across Custer City'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 1,353 people through 2 water systems.
| System name | PWSID | Population | Source |
|---|---|---|---|
| CUSTER COUNTY RWD #3 | OK2002040 | 960 | Groundwater |
| CUSTER CITY PWS | OK2002009 | 393 | Groundwater |
Water bodies near Custer City
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on Custer City'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.
Flood & storm history
4 federal disaster declarations on record for Custer County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Custer County is in D3 (extreme drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Custer City compares
Scores for nearby Oklahoma cities on one line, with the average marked.
dashed line = Oklahoma average (45/100)
Custer City scores 78.6/100 — above the Oklahoma average of 45/100. It outscores 9 of 10 nearby cities. Full Oklahoma rankings →
38.6 / 100DTulsa, OK
48.5 / 100FBroken Arrow, OK
43.9 / 100FNorman, OK
38.4 / 100FLawton, OK
44.4 / 100FEdmond, OK
34.9 / 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 Custer City's water — not generic advice.
Filter drinking & cooking water
NSF-certified water filter. Lead detected at 6.5 ppb
Compare tested filters →Flush taps & check your service line
Lead leaches from pipes as water sits. Run cold water 30 seconds before drinking (especially mornings), and ask the utility whether your address still has a lead service line.
Lead risks explained →Watch for Custer City 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 Custer City, OK tap water safe to drink?
Custer City's water quality earned a grade of B (78.6/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #87 out of 357 cities tested in Oklahoma.
What contaminants are in Custer City's water?
Lead was measured at 6.5 ppb (90th percentile). 7 violations are on record.
How is Custer City'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 Custer City?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Custer City's water come from?
Custer City's water is sourced from Groundwater. The city has 2 water systems serving approximately 1,353 residents.
What health violations has Custer City's water system had?
Custer City has 2 health-based violations on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 4 violations remain unresolved.
Is Custer City's groundwater at risk of contamination?
Custer City 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 7 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 Custer City's water compare to other cities?
Custer City ranks #87 out of 357 cities in Oklahoma (better than 76% of state cities) and #8507 out of 15382 cities nationally (45th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.