Public Works

SEWER MAINTENANCE EFFECTIVENESS: Sanitary sewer overflows per 100 miles of main

Current Value

2.75

2024

Definition

This data is derived from IPS (Infor Public Sector), the BES asset management and maintenance/work order database; the geographic representation of that information can be publicly viewed in Portland Maps under “Sewer Assets”.
IPS maintains data attribution of each individual sewer asset, including linear feet of each sewer main and lateral. Data is categorized by type of system (combined, sanitary, and storm), type of asset (force main, gravity main, culvert and ditches (storm only), or public lateral). It also includes asset counts for linear feet per asset and individual units for things like maintenance holes, access structures, and stormwater facilities. At the end of each fiscal year, BES staff run a report out of IPS for the length of the sanitary and combined sewer mains (force mains plus gravity mains, not including the public portion of the service laterals) that are in service (active status) and maintained by the City (not maintained and/or owned by other public or private entities).
Each sewage release that is reported to the City is investigated to determine where the cause of the sewage release was located and what was the cause of the release. The sewage release record is also found in IPS and is attached to the asset associated with the original complaint. The sewage release records includes the original complaint information, the initial site investigation information, and the final determination of the cause of the sewage release. Only sewage releases that are caused by issues located in a public sewer main, maintenance hole located on a public sewer main, or associated with a pump station are included in the calculation. For examples, clogs in private laterals on private property are not included in the calculation, as these would be maintenance issues caused by the property owner, not due to defects or lack of maintenance in the public sewer system.
BES staff are involved in verifying and reporting each sewage release to Oregon Department of Environmental Quality. The CMOM Program Report summarizes the reporting, calculation, and quality assurance process, which includes individual sanitary sewer overflow reporting and notification, monthly checks for investigation completeness, and submittal as part of the annual regulatory compliance report.
At the end of the fiscal year, once all data has been checked and verified, BES staff query IPS for verified sewage release records (release occurred) for location of the sewage release cause (BES maintained sanitary gravity sewer, BES maintained sanitary force main, BES maintained combined gravity sewer, BES maintained combined force main, BES maintained pump stations, BES maintained combined maintenance hole, BES maintained sanitary maintenance hole)).

This data is derived from IPS (Infor Public Sector), the BES asset management and maintenance/work order database; the geographic representation of that information can be publicly viewed in Portland Maps under “Sewer Assets”.&nbsp; 
IPS maintains data attribution of each individual sewer asset, including linear feet of each sewer main and lateral. &nbsp;Data is categorized by type of system (combined, sanitary, and storm), type of asset (force main, gravity main, culvert and ditches (storm only), or public lateral). It also includes asset counts for linear feet per asset and individual units for things like maintenance holes, access structures, and stormwater facilities. &nbsp;At the end of each fiscal year, BES staff run a report out of IPS for the length of the sanitary and combined sewer mains (force mains plus gravity mains, not including the public portion of the service laterals) that are in service (active status) and maintained by the City (not maintained and/or owned by other public or private entities).&nbsp; 
Each sewage release that is reported to the City is investigated to determine where the cause of the sewage release was located and what was the cause of the release. &nbsp;The sewage release record is also found in IPS and is attached to the asset associated with the original complaint. &nbsp;The sewage release records includes the original complaint information, the initial site investigation information, and the final determination of the cause of the sewage release. &nbsp;Only sewage releases that are caused by issues located in a public sewer main, maintenance hole located on a public sewer main, or associated with a pump station are included in the calculation. &nbsp;For examples, clogs in private laterals on private property are not included in the calculation, as these would be maintenance issues caused by the property owner, not due to defects or lack of maintenance in the public sewer system. &nbsp; 
BES staff are involved in verifying and reporting each sewage release to Oregon Department of Environmental Quality. &nbsp;The CMOM Program Report summarizes the reporting, calculation, and quality assurance process, which includes individual sanitary sewer overflow reporting and notification, monthly checks for investigation completeness, and submittal as part of the annual regulatory compliance report.&nbsp; 
At the end of the fiscal year, once all data has been checked and verified, BES staff query IPS for verified sewage release records (release occurred) for location of the sewage release cause (BES maintained sanitary gravity sewer, BES maintained sanitary force main, BES maintained combined gravity sewer, BES maintained combined force main, BES maintained pump stations, BES maintained combined maintenance hole, BES maintained sanitary maintenance hole)). &nbsp;&nbsp;

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Why Is This Important?

Regulatory permits require the City to maintain its wastewater collection system in a way that reduces public health and environmental risk. Sanitary sewer overflows (SSOs) are unplanned releases of sewage from the sanitary and combined (sanitary and stormwater in the same pipe) sewer system.

These releases can occur due to structural failure (broken pipes or connections), blockages (debris, grease, or roots), mechanical failure (pump station outages), the system being hydraulically overloaded (heavy rain events beyond the City’s design standards for service), or factors beyond BES control (significant power outages, severe weather, or debris in private sanitary laterals). SSOs are an indicator of the overall effectiveness of maintenance programs.

What Do The Numbers Show?

The Bureau of Environmental Services (BES) has a target of no more than 5 SSOs per 100 miles of sanitary and combined sewer system (including public laterals). The values shown do not include public laterals. The actual results show that BES is effectively reducing overflows and well below our target. BES has a proactive preventative maintenance program to inspect, clean, and repair sanitary and combined sewer mains and to maintain pump stations. BES continues to improve at this performance measure and has been successful at reaching the target for the last three fiscal years.

How Did We Arrive at These Numbers?

All complaints of sewage releases are routed to the Maintenance Dispatch hotline (503-823-1700), which is able to deploy emergency sewer crews 24/7. These sewer crews confirm whether or not a sewage release occurred, and if so, if the cause was located in the public sewer.

BES completes an initial investigation of cause, and if due to a blockage or structural issue, begin an emergency repair. The sewer crews notify the Spill Protection and Community Response 24/7 hotline, and the on-call Duty Officer reports SSOs to the Oregon Department of Environmental Quality as required by the wastewater permit.

The number of SSO’s is calculated from sewage releases that were caused by an issue in the public sewer main. Then, BES calculates the length of sanitary and combined sewer mains. The performance measure is the number of SSOs divided by the length of sanitary and combined sewer main.

Where Can I Find More Information?

BES submits an annual report to DEQ on annual wastewater permit performance and compliance. All final reports are available on Efiles - Annual CSO and CMOM Reports. Additional information about wastewater regulatory compliance can be found at Efiles - CBWTP NPDES Permit Supporting Records - CMOM.

See What you can (and can't) flush for more information on ways that everyone can help prevent sewage releases. All suspected sewage releases should be reported immediately to 503-823-1700. More information can be found at Report a Sewer Problem.

Clear Impact Suite is an easy-to-use, web-based software platform that helps your staff collaborate with external stakeholders and community partners by utilizing the combination of data collection, performance reporting, and program planning.