CMOM, FOG control, asset management, customer complaints, and public communication
Key Takeaways
- CMOM means Capacity, Management, Operation, and Maintenance; it is a practical framework for preventing SSOs and showing that a utility manages its system proactively.
- A strong CMOM program links maps, asset inventory, preventive maintenance, complaint history, pump station data, CCTV findings, and capital planning.
- FOG control is both maintenance and source control: cleaning a grease blockage fixes the immediate problem, but inspections, interceptors, education, and enforcement reduce recurrence.
- Customer complaints are operational data; repeat backups, odors, slow drains, and manhole observations can reveal roots, sags, inflow, grease, or capacity constraints.
- Public communication should be prompt, accurate, and coordinated; operators report facts through the chain of command and avoid speculation.
CMOM turns field work into system control
Capacity, Management, Operation, and Maintenance (CMOM) is a framework for managing a wastewater collection system so it has adequate capacity, is operated by trained staff, is maintained before failure, and is improved based on evidence. EPA materials describe CMOM and similar management, operation, and maintenance approaches as tools for improving Clean Water Act compliance and reducing sanitary sewer overflows.
The exam usually tests CMOM as applied judgment. If a question asks what a utility should do after repeat overflows, the best answer is not just more emergency cleaning. The best answer usually combines cause analysis, preventive maintenance, capacity evaluation, records, and follow-up.
Four CMOM lenses
| Lens | What it asks | Examples of evidence |
|---|---|---|
| Capacity | Can the system convey peak wet-weather and dry-weather flows? | Flow monitoring, rain data, surcharge history, hydraulic model, pump station run times |
| Management | Does the utility have authority, staffing, budget, training, and procedures? | Sewer use ordinance, SOPs, training records, emergency plan, budget history |
| Operation | Are daily decisions keeping the system stable? | SCADA trends, alarm response, pump alternation, odor control, customer response logs |
| Maintenance | Is work preventive, risk-based, and documented? | Cleaning schedule, CCTV ratings, root-control program, FOG inspections, work orders |
FOG control is source control
Fats, oils, and grease (FOG) cool and solidify in pipes, especially where flow is slow, pipe grade is flat, or hot restaurant discharge mixes with cooler wastewater. Jetting may restore flow, but the long-term fix is source control.
A good FOG program typically includes food service establishment inventory, grease interceptor requirements, inspection frequency, pump-out records, enforcement authority, education, and follow-up cleaning of known hot spots. Residential outreach also matters because household grease contributes to blockages.
Asset management: make the map match reality
Collection system assets include gravity mains, manholes, force mains, air release valves, siphons, pump stations, wet wells, generators, controls, and flow meters. Asset management means the utility knows what it owns, where it is, what condition it is in, how critical it is, and what work is planned next.
For exam questions, separate condition from criticality. A shallow dead-end line with minor roots may be poor condition but low consequence. A force main under a river, a pump station serving a hospital, or a trunk sewer with no bypass option may be high criticality even before it fails.
Customer complaints are data
A complaint about sewage odor, repeated lateral backups, or a surcharging manhole should create a record and a response. The operator should collect location, time, weather, fixture or manhole observations, whether nearby customers are affected, and whether the problem appears public or private.
Do not promise liability decisions in the field. Communicate what you can verify: what you observed, what immediate action is being taken, and how the customer will receive follow-up. Escalate media questions, public notices, and regulatory statements to the designated utility spokesperson or supervisor.
Common exam contrasts
- Reactive maintenance: crew responds only after blockages, backups, and alarms.
- Preventive maintenance: crew cleans and inspects on a schedule based on known risk.
- Predictive or risk-based maintenance: crew uses CCTV, work history, flow data, pipe age, material, and consequence of failure to prioritize work.
- Source control: utility reduces what enters the sewer, such as FOG, roots through defective laterals, sump pumps, or prohibited industrial discharges.
- Capital improvement: utility rehabilitates or replaces assets when maintenance cannot provide reliable service.
A downtown restaurant area has three grease-related blockages in six months. Each time, the crew jets the line and restores flow. What is the best CMOM-based follow-up?
Match each CMOM element with the best example.
Match each item on the left with the correct item on the right
A homeowner reports sewage odor and slow drains after heavy rain. Nearby manholes show high flow but no overflow. What is the best operator response?