Glossary of terms

Sewer manhole

A sewer manhole is a structure placed along a sewer line to connect sections, change direction, slope or diameter, and provide maintenance access. On a longitudinal profile it is a node where you read the invert level, ground level and installation depth. The difference between inlet and outlet invert levels shows the drop through the manhole. Typical types include junction, drop and inspection manholes. When checking a profile, confirm that the outlet invert is not higher than the inlet invert and that spacing between manholes allows the sewer to be cleaned.