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PWS ID	OR4100457
PWS Name	LAKE OSWEGO MUNICIPAL WATER
PWS Type	Community water system
Owner Type	Local government
Primary Source	Surface water purchased
Primacy Type	State
Is Wholesaler?	No
Population Served	40000
County Served	Clackamas

The tables below list all violations that the state reported to EPA for this water system. Health-based violations are listed first, followed by treatment technique, MRDL, monitoring, reporting, and other violations.

Health-based	Violations of maximum contaminant levels (MCLs) or maximum residual disinfectant levels (MRDLs), which specify the highest concentrations of contaminants or disinfectants, respectively, allowed in drinking water; or of treatment technique (TT) rules, which specify required processes intended to reduce the amounts of contaminants in drinking water. MCLs, MRDLs, and treatment technique rules are all health-based drinking water standards.
Maximum Contaminant Level or MCL	The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.
Treatment Technique	A required process intended to reduce the level of a contaminant in drinking water.
Maximum residual disinfectant level or MRDL	The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.
Monitoring & reporting	Failure to conduct regular monitoring of drinking water quality, as required by SDWA, or to submit monitoring results in a timely fashion to the primacy agency or EPA.
Public notification & other	Failure to provide notification to the public as required by the Violations of Public Notification Rule and the Consumer Confidence Report Rule, and violations of other requirements such as those violations related to variances and exemptions.

Violations

Violation Category Code	Violation Type Description	Rule Name	Contaminant Name	Violation ID	Compliance Status Description	Compliance Period Begin Date	Compliance Period End Date	Is Health Based Ind
Other	Consumer Confidence Report Complete Failure to Report	Consumer Confidence Rule	Consumer Confidence Rule	900692820	Returned to Compliance	01-JUL-2025	-	No
Other	Consumer Confidence Report Complete Failure to Report	Consumer Confidence Rule	Consumer Confidence Rule	900692819	Returned to Compliance	01-JUL-2024	-	No
MR	Monitoring and Reporting (DBP)	Stage 1 Disinfectants and Disinfection Byproducts Rule	Bromate	900692817	Returned to Compliance	01-JAN-2019	31-MAR-2019	No
MR	Monitoring, Routine Minor (TCR)	Total Coliform Rule	Coliform (TCR)	695309	Returned to Compliance	01-AUG-2009	31-AUG-2009	No
MR	Monitoring, Regular	Synthetic Organic Chemicals	2,4-D	692908	Returned to Compliance	01-APR-2008	30-JUN-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Toluene	694909	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Benzene	694809	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	CHLOROBENZENE	694709	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Tetrachloroethylene	694609	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	1,1,2-Trichloroethane	694509	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Trichloroethylene	694409	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	1,2-Dichloropropane	694309	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Carbon tetrachloride	694209	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	1,1,1-Trichloroethane	694109	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	1,2-Dichloroethane	694009	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	trans-1,2-Dichloroethylene	693909	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	1,1-Dichloroethylene	693809	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Vinyl chloride	693709	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	p-Dichlorobenzene	693609	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	o-Dichlorobenzene	693509	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	DICHLOROMETHANE	693409	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Xylenes, Total	693309	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	cis-1,2-Dichloroethylene	693209	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	1,2,4-Trichlorobenzene	693109	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Nitrate Rule	Nitrate	695209	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Ethylbenzene	695009	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Volatile Organic Chemicals	Styrene	695109	Returned to Compliance	01-JAN-2008	31-DEC-2008	No
MR	Monitoring, Regular	Synthetic Organic Chemicals	2,4-D	693008	Returned to Compliance	01-JAN-2008	31-MAR-2008	No
MR	Monitoring, Regular	Nitrate Rule	Nitrate	691303	Returned to Compliance	01-JAN-2002	31-DEC-2002	No
TT	OCCT/SOWT Treatment Installation/Demonstration	Lead and Copper Rule	Lead and Copper Rule	691198	Returned to Compliance	01-JAN-2000	-	Yes
MR	Monitoring, Routine Minor (TCR)	Total Coliform Rule	Coliform (TCR)	185296	Returned to Compliance	01-JAN-1996	31-JAN-1996	No
MR	Monitoring, Routine Minor (TCR)	Total Coliform Rule	Coliform (TCR)	60396	Returned to Compliance	01-DEC-1995	31-DEC-1995	No
MR	Monitoring, Routine Minor (TCR)	Total Coliform Rule	Coliform (TCR)	32896	Returned to Compliance	01-NOV-1995	30-NOV-1995	No
MR	Monitoring, Routine Minor (TCR)	Total Coliform Rule	Coliform (TCR)	3296	Returned to Compliance	01-OCT-1995	31-OCT-1995	No
MR	Monitoring, Regular	Radionuclides and Revised Rad Rule	Gross Alpha, Excl. Radon and U	6512580	Known	01-JUN-1976	31-MAY-1980	No
MR	Monitoring, Regular	Radionuclides and Revised Rad Rule	Combined Radium (-226 and -228)	6512780	Known	01-JUN-1976	31-MAY-1980	No

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Enforcement Actions

Latest Enforcement ID	Associated To Violation ID	Enforcement Action Type Code	Enforcement Action Description	Enforcement Date	Originator Description	Enforcement Comment
9469017	900692820	SOX	State Compliance achieved	02-SEP-2025	State	-
9469016	900692819	SOX	State Compliance achieved	03-JUL-2024	State	-
9469015	900692817	SOX	State Compliance achieved	08-APR-2019	State	-
28	695309	SOX	State Compliance achieved	02-OCT-2009	State	-
37	693909	SOX	State Compliance achieved	04-MAY-2009	State	-
1	695209	SOX	State Compliance achieved	04-MAY-2009	State	-
49	695109	SOX	State Compliance achieved	04-MAY-2009	State	-
48	695009	SOX	State Compliance achieved	04-MAY-2009	State	-
47	694909	SOX	State Compliance achieved	04-MAY-2009	State	-
46	694809	SOX	State Compliance achieved	04-MAY-2009	State	-
45	694709	SOX	State Compliance achieved	04-MAY-2009	State	-
44	694609	SOX	State Compliance achieved	04-MAY-2009	State	-
29	693109	SOX	State Compliance achieved	04-MAY-2009	State	-
30	693209	SOX	State Compliance achieved	04-MAY-2009	State	-
31	693309	SOX	State Compliance achieved	04-MAY-2009	State	-
32	693409	SOX	State Compliance achieved	04-MAY-2009	State	-
33	693509	SOX	State Compliance achieved	04-MAY-2009	State	-
34	693609	SOX	State Compliance achieved	04-MAY-2009	State	-
35	693709	SOX	State Compliance achieved	04-MAY-2009	State	-
36	693809	SOX	State Compliance achieved	04-MAY-2009	State	-
38	694009	SOX	State Compliance achieved	04-MAY-2009	State	-
39	694109	SOX	State Compliance achieved	04-MAY-2009	State	-
40	694209	SOX	State Compliance achieved	04-MAY-2009	State	-
41	694309	SOX	State Compliance achieved	04-MAY-2009	State	-
42	694409	SOX	State Compliance achieved	04-MAY-2009	State	-
43	694509	SOX	State Compliance achieved	04-MAY-2009	State	-
9469009	693008	SOX	State Compliance achieved	16-MAR-2009	State	SOC snc 94605
9469009	692908	SOX	State Compliance achieved	16-MAR-2009	State	SOC snc 94605
9468703	691303	SOX	State Compliance achieved	03-JUN-2003	State	VALIDATED Migrated SOX 08/30/2004 Due to Sample #03106/03I Taken 04/16/2003.
24	3296	SOX	State Compliance achieved	24-JUL-2001	State	-
25	32896	SOX	State Compliance achieved	24-JUL-2001	State	-
26	60396	SOX	State Compliance achieved	24-JUL-2001	State	-
27	185296	SOX	State Compliance achieved	24-JUL-2001	State	-
9468600	691198	SOX	State Compliance achieved	01-MAR-2000	State	VALIDATED Treatment installed, two good rounds complete, pH set

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All Facilities

Facility Name	Facility ID	Is Source	Facility Type Description	Water Type Description	Availability Description	Facility Activity Status
LAKE OSWEGO-TIGARD WATER SUPPLY - 01542	25847	Yes	Consecutive Connection	Surface water	Permanent	Active
WELL #2	2092	Yes	Well	Ground water	Other	Inactive
CLACKAMAS RIVER	11805	Yes	Intake	Surface water	Permanent	Inactive
COMMON HEADER FOR WTP-A	19231	No	Common Headers	-	-	Inactive
COMMON HEADER FOR WTP-B	19232	No	Common Headers	-	-	Inactive
DISTRIBUTION SYSTEM	7067	No	Distribution System/Zone	-	-	Active
EP FOR LAKE OSWEGO - TIGARD WATER SUPPLY	25848	No	Sampling Station	-	-	Active
EP WELL #2	12120	No	Sampling Station	-	-	Inactive
EP FOR CLACKAMAS RIVER	17297	No	Sampling Station	-	-	Inactive
TP FOR CLACKAMAS RIVER	219	No	Treatment Plant	-	-	Inactive
TP FOR WELL #2	220	No	Treatment Plant	-	-	Inactive

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Treatment Processes

Facility Name	Facility ID	Treatment Process	Treatment Objective
TP FOR CLACKAMAS RIVER	219	Filtration, Rapid Sand	Particulate removal
TP FOR CLACKAMAS RIVER	219	Rapid Mix	Particulate removal
TP FOR CLACKAMAS RIVER	219	Sedimentation	Particulate removal
TP FOR CLACKAMAS RIVER	219	Hypochlorination, Post	Disinfection
TP FOR CLACKAMAS RIVER	219	Coagulation	Particulate removal
TP FOR CLACKAMAS RIVER	219	Flocculation	Particulate removal
TP FOR CLACKAMAS RIVER	219	Innovative	Corrosion control
TP FOR CLACKAMAS RIVER	219	Ozonation, Pre	Disinfection

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For more information on a Water System:
Ask the operators of your water system, contact your primacy agency or file a Freedom of Information Act (FOIA) request.
Drinking water in general: Find out more about your drinking water web site or call the Safe Drinking Water Hotline (1-800-426-4791). EPA has also prepared a table about various regulated drinking water contaminants.
Tools for accessing EPA drinking water data: Safe Drinking Water Information System (SDWIS) Federal Reporting Services and Drinking Water Performance and Results Report.
Research Data: As well as monitoring the levels of drinking water contaminants for which EPA has set standards, EPA, states, and water systems also carry out studies of contaminants that may need to be regulated in the future. For more information about these contaminants, please see the National Contaminant Occurrence Database.

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