What it means
Manholes allow inspection, cleaning, and flow changes, but they can also admit inflow through lids, frames, walls, joints, or pipe connections. Corrosion, bench damage, and structural defects can create operational and safety problems.
What operators watch
- Inspect lids, frames, walls, steps, channels, benches, and pipe connections.
- Look for staining, roots, corrosion, infiltration, and surcharge marks.
- Use safe traffic control and confined-space awareness around open manholes.
Common exam traps
- Ignoring manholes during I&I investigations.
- Assuming visual surface condition tells the whole story.
- Forgetting fall hazards and atmospheric hazards.
Field example
A manhole with clear water entering through wall joints during wet weather may be targeted for sealing or rehabilitation.
