Sewer and Wastewater Asset Management Plans: What to Include and How to Keep Them Current

A sewer and wastewater asset management plan has one job: to say, with evidence, which pipes, pump stations and treatment assets should be renewed in which order, what that costs, and what happens if the money does not come. Most plans do the first part once and never do it again. This guide covers what the plan needs to contain and, just as important, how to keep it current with a small staff.

Why Collection Systems Need Their Own Plan

Collection systems are buried, inspected a few hundred feet at a time, and fail in ways that are expensive and public: overflows, sinkholes, backups into basements. The data that describes them comes from CCTV, not from a walk-around. That shapes everything about the plan: the condition method, the inspection cycle, the risk model and the renewal options.

Treatment plant assets are different again. They are above ground, mechanical and electrical, and their criticality comes from process position rather than pipe size. A good plan treats the two with separate methods under one risk scale.

The Inventory and the Condition Record

For the collection system, the inventory lives in GIS: every pipe segment, manhole, lateral connection point, pump station and force main, with material, diameter, depth, install year and a replacement cost basis. Condition comes from CCTV coded to the NASSCO PACP standard for pipe, MACP for manholes and LACP for laterals, with the quick structural and O&M ratings stored per segment with the inspection date.

Set an inspection cycle you can afford and keep. Ten years for the whole system is a common target; higher-risk segments go more often. A plan that assumes an inspection program the budget cannot support is already out of date.

For the plant, the inventory is the equipment list from the CMMS: each pump, blower, clarifier mechanism, switchgear and instrument, with a condition rating from the maintenance staff and a process-criticality rating from operations.

Risk: Likelihood Times Consequence

Likelihood of failure for pipe draws on the PACP structural rating, age against expected life for the material, and history of blockages and repairs. Consequence of failure depends on diameter, depth, flow, what the pipe runs under, whether a failure would reach a waterway, and whether the segment is a single point of failure for an area. Score each on a 1 to 5 scale, multiply, and rank.

For plant assets, consequence is process-driven: can the plant keep its permit if this unit is down, for how long, and is there a standby. The same 5 by 5 matrix keeps plant and pipe on one list for capital decisions.

Renewal Strategies and the Capacity Question

The plan should name the renewal method by condition and situation: point repair, cured-in-place lining, pipe bursting, or open-cut replacement, each with a unit cost the utility has actually seen in recent bids. Lining a pipe that needs more capacity is a wasted project, so the plan also needs the capacity view: inflow and infiltration by basin, a capacity, management, operation and maintenance (CMOM) program, and the hydraulic model where one exists.

The Regulatory Thread

In Oregon, DEQ permits and the Clean Water State Revolving Fund set expectations for overflow reporting, CMOM and, for loan-funded treatment works, a fiscal sustainability plan. In Washington, Ecology's General Sewer Plan requirements and its revolving fund do the same work. Sanitary sewer overflow reporting, consent order milestones and NPDES permit conditions all draw on the same records the plan uses. Build the plan so those reports come from the plan's data rather than from a separate effort.

The CIP Tie-In

A plan that stops at a ranked list has not finished. The next step is a 10 to 20 year renewal program: projects grouped by basin and by coordination with street work, phased against the annual investment the rate base can support, with the backlog and its condition consequence shown year by year. This is the page the council and the rate consultant actually read.

Keeping the Plan Current

The plan ages the day it is adopted. A yearly refresh is enough if the data flows: CCTV results update the condition record as they are coded; CMMS work orders update repair history; completed projects reset condition and age; the risk ranking re-runs; the renewal program rolls forward a year. The refresh is a week of work when the systems are connected and a quarter when they are not.

Where AMP Fits

AMP's asset management consulting covers the register and data readiness, PACP-based condition programs, risk-based prioritization aligned to ISO 55001, renewal planning, CIP prioritization and GASB 34 and 96 support, on the GIS, CMMS and Microsoft 365 tools a utility already runs. AMP Insight carries the register, the risk ranking and the capital plan on one screen, with the inputs behind every number and the as-of date on every view. We work directly with utilities and as a subconsultant to engineers of record.

Practical Takeaways

• GIS holds the collection system inventory; the CMMS holds the plant inventory; one risk scale covers both.
• Code CCTV to PACP and store the ratings per segment with the inspection date.
• Set an inspection cycle the budget can sustain, and rank with likelihood times consequence.
• Name the renewal method and its unit cost; check capacity before lining.
• Build the overflow, CMOM and loan deliverables so they come from the plan's own data.
• Finish with a phased renewal program and a yearly refresh on the calendar.

The free infrastructure failure analyzer gives a first-pass failure probability by asset class and age, a useful starting point before the CCTV data is complete.