Community Water System · PWS IL0315185
Oasis MHP
Operator location Northbrook, Illinois - upper-third violation load (> 74 violations) with 101 EPA violations; groundwater source; 3,000 served (PWS-level, not municipal population).
- 3,000
- People served (this PWS)
- 101
- EPA violations (this PWS)
- 20
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Oasis MHP standing, high SDWIS violation third
101 EPA SDWIS violations on record - upper-third violation load (> 74 violations). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 20% is middle-third health share (≤ 23%). Population rank #10,608 of 29,740 among systems serving 500+.
The verdict
Oasis MHP sits in the upper third of the sitemap cohort by violation count (101), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is mid-pack at 3,000 (mid served population (≤ 3,309)). Health-based share is 20% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- #10,608 of 29,740
- Population · /systems
- #477 of 1,310
- Population · IL
- 101
- Total EPA violations on record
- 20%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 599
- County
- Cook
- School/Daycare
- No
- MCL Violations
- 20
- Monitoring Violations
- 62
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 20 | 1997 |
| Coliform (TCR) | MR | 14 | 1997 |
| Chlorine | MR | 4 | 2011 |
| TTHM | MR | 4 | 2021 |
| Total Haloacetic Acids (HAA5) | MR | 4 | 2021 |
| Antimony, Total | MR | 4 | 2020 |
| Beryllium, Total | MR | 4 | 2020 |
| Nickel | MR | 4 | 2020 |
| Selenium | MR | 4 | 2020 |
| Barium | MR | 4 | 2020 |
| Mercury | MR | 4 | 2020 |
| Total Polychlorinated Biphenyls (PCB) | MR | 4 | 2020 |
| Cadmium | MR | 4 | 2020 |
| Thallium, Total | MR | 4 | 2020 |
| Consumer Confidence Rule | Other | 2 | 2012 |
Violation Count vs. the National Corpus
Oasis MHP has 101 recorded EPA violations, 73% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 26% carry more. 20% of this system's own violations are health-based (20 of 101), and it ranks #10,608 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
101 Around the middle fewer violations than 26% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
SDWIS compliance record for Oasis MHP
101 violations on record for IL0315185; use EPA SDWIS to confirm return-to-compliance dates and monitoring categories.
Sources: EPA SDWIS · Illinois EPA, Bureau of Water
Nationwide peers
101 violations · 3,000 served: nearest cross-state SDWIS matches.
Cross-state systems with comparable violation load
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
Cross-state systems near this population served
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Oasis MHP
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Illinois compares on the same EPA violation measures. Illinois systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.