Manhole inspections

Manhole Inspections

Manhole inspections are generally performed to give an accurate representation of the sewer’s collection system.  They help to determine structural damage to the chamber, assess inflow and infiltration concerns, discover the size of incoming and outgoing pipes and show evidence of surcharge conditions.

Common causes of manhole problems include corrosion, cracks/fractures, displaced joints, deposits in the channel and infiltration.  Leaks can be caused by poorly-fit covers, shifted frames and damaged adjusting rings.

SWS field technicians thoroughly inspect all components of the manhole including cover condition, ring size, structure material, depth to invert measurements, channel flow and any surcharge conditions.  Using a digital camera to record the inspection, further enhances the reporting documentation.

Manhole inspections are the most cost-effective way to assess sewer collection system concerns.

Measuring manhole depths

· Reveals structural issues

· Identifies I/I concerns

· Obtains rim to invert and depth to invert measurements

· Assesses wall materials

· Inventories cover conditions

· Assists in updating drawings and GIS mapping systems


Lined manholeHidden manholeBrick manholeOffset manhole

Manhole inspections identify construction material, such as brick (upper left) and defects such as offset (upper right).

They can locate cleverly buried manholes (bottom left) and identify connections missing from GIS maps (bottom right).