Non-Transient Non-Community Water System · PWS OR4194894
Arbor School
Operator location Tualatin, Oregon - smaller served population (≤ 999) at 215 people served; 151 SDWIS violations on record from groundwater sources.
- 215
- People served (this PWS)
- 151
- EPA violations (this PWS)
- 4
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Arbor School standing, high SDWIS violation third
215 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 3% is middle-third health share (≤ 23%).
The verdict
Arbor School sits in the upper third of the sitemap cohort by violation count (151), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (215; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 3% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 151
- Total EPA violations on record
- 3%
- Health-based (MCL / treatment failure)
- 215
- People served by this PWS (SDWIS)
- N/A
- PFAS compounds detected (UCMR5)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Non-Transient Non-Community
- Owner Type
- Local
- Connections
- 1
- County
- Clackamas
- School/Daycare
- Yes
- MCL Violations
- 0
- Monitoring Violations
- 145
- Treatment Tech Violations
- 4
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 52 | 2016 |
| Revised Total Coliform Rule | MON | 17 | 2020 |
| Lead and Copper Rule | MR | 12 | 2011 |
| Nitrate | MR | 5 | 2008 |
| E. COLI | MR | 5 | 2020 |
| Revised Total Coliform Rule | TT | 4 | 2019 |
| Benzo(a)pyrene | MR | 2 | 2020 |
| Heptachlor epoxide | MR | 2 | 2020 |
| Heptachlor | MR | 2 | 2020 |
| Atrazine | MR | 2 | 2020 |
| Di(2-ethylhexyl) adipate | MR | 2 | 2020 |
| Methoxychlor | MR | 2 | 2020 |
| Endrin | MR | 2 | 2020 |
| Public Notice | Other | 2 | 2019 |
| HEXACHLOROBENZENE | MR | 2 | 2020 |
| LASSO | MR | 2 | 2020 |
| Hexachlorocyclopentadiene | MR | 2 | 2020 |
| Di(2-ethylhexyl) phthalate | MR | 2 | 2020 |
| Simazine | MR | 2 | 2020 |
| BHC-GAMMA | MR | 2 | 2020 |
| Endothall | MR | 1 | 2005 |
| Dalapon | MR | 1 | 2005 |
| Toxaphene | MR | 1 | 2005 |
| cis-1,2-Dichloroethylene | MR | 1 | 2005 |
| DICHLOROMETHANE | MR | 1 | 2005 |
| p-Dichlorobenzene | MR | 1 | 2005 |
| Vinyl chloride | MR | 1 | 2005 |
| 1,1-Dichloroethylene | MR | 1 | 2005 |
| 1,2-Dichloroethane | MR | 1 | 2005 |
| Carbon tetrachloride | MR | 1 | 2005 |
Violation Count vs. the National Corpus
Arbor School has 151 recorded EPA violations, 81% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 19% carry more. 3% of this system's own violations are health-based (4 of 151), and it ranks unranked by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
151 Higher than most more violations than 81% 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
Population served record for Arbor School
EPA SDWIS lists 215 people served and 1 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
151 violations · 215 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.
What to do with Arbor School
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Oregon compares on the same EPA violation measures. Oregon 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.