GLOSSARY
Underground Utility and Excavation Glossary
53 terms in plain English, from 811 and bedding to thrust blocks and wet wells.
- 53 terms
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- 811
- The national number to call before you dig, which connects you to your state’s one-call center so utilities can mark their buried lines.
A
- APWA color code
- The standard set of colors used for utility marking paint and flags, such as red for electric, yellow for gas and blue for water.
- As-built
- A drawing that records where utilities and structures were actually installed, which can differ from the original plan.
- Auger boring
- A trenchless method that pushes steel casing through the ground while an auger inside removes soil, also called jack and bore.
B
- Backfill
- The soil or stone placed back into an excavation after pipe or conduit is installed.
- Bedding
- The layer of sand or crushed stone placed under and around a pipe to support it evenly.
- Belly
- A low spot or sag in a sewer pipe where water and solids collect instead of draining.
- Benching
- Cutting the sides of an excavation into steps to keep the walls stable and safe.
- Bentonite
- A clay used in drilling fluid for directional drilling to stabilize the hole and carry cuttings out.
- Boring pit
- The entry or receiving pit dug at either end of a trenchless crossing.
C
- Catch basin
- A drainage structure with a grate that collects surface water and sends it into a storm pipe.
- Cleanout
- A capped access point on a sewer line that allows inspection and clearing.
- Compaction
- Making soil denser by mechanical force so it does not settle later.
- Competent person
- A person who can identify excavation hazards and has authority to correct them, required on trench sites under safety rules.
- Conduit
- A pipe or tube that protects electrical or communications cable underground.
- Cubic yard
- A volume of 27 cubic feet, the common unit for measuring soil, stone and concrete.
- Culvert
- A pipe or tunnel that carries water under a road, driveway or embankment.
D
- Dewatering
- Removing water from an excavation with pumps or sumps so work can continue.
- Directional drilling
- A trenchless method that steers a drill bit along an underground path and pulls pipe or conduit back through the hole.
- Drain field
- The part of a septic system where treated liquid soaks into the soil.
- Duct bank
- A group of conduits encased together in the ground, often in concrete.
- Ductile iron
- A strong iron pipe material used for water mains and fire lines.
E
- Easement
- A recorded legal right for a utility or other party to use part of a property for a specific purpose.
F
- Force main
- A pressurized sewer pipe that carries wastewater from a pump station to a higher point.
- French drain
- A trench with filter fabric, stone and perforated pipe that collects and carries away groundwater.
G
- Grade
- The slope or elevation of the ground or a pipe.
- Gravity sewer
- A sewer that works by sloping downhill without pumps.
H
- Handhole
- A small underground box that gives access to conduit and cable at intervals.
- HDPE
- High-density polyethylene, a flexible plastic pipe used for conduit, water, gas and trenchless installations.
I
- Invert
- The inside bottom of a pipe, whose elevation is used to set grade.
J
- Jack and bore
- Another name for auger boring under roads, using steel casing.
L
- Lateral
- The smaller pipe that connects a building to a sewer main.
- Lift
- A layer of backfill placed and compacted before the next layer goes in.
- Lift station
- A pump station that lifts wastewater to a higher elevation when gravity cannot carry it.
- Locate
- The marking of buried utilities on the ground after an 811 request.
M
- Main
- A large utility pipe, usually in the street, that serves many properties.
- Manhole
- A vertical access structure on a sewer or storm line, with a removable cover at the surface.
P
- Pothole
- A small hole dug to expose and verify a buried utility.
- Precast
- Concrete structures made in a factory and delivered to the site, such as manholes and vaults.
- Protective system
- Sloping, benching, shoring or a trench box used to keep trench walls from collapsing.
R
- Right-of-way
- Land used for a road or utility, where permits are usually needed to dig.
- Riser
- A vertical pipe or access that brings a buried component, such as a septic tank, to the surface.
S
- Shoring
- Supports installed in an excavation to hold the walls in place.
- Spoil
- Soil removed from an excavation.
- Stub-up
- The end of a pipe or conduit left sticking up above grade for later connection.
- Swale
- A shallow channel that carries surface water across a lot.
T
- Tap
- The connection of a service line to a utility main.
- Thrust block
- A concrete mass poured against a pipe fitting to resist the force of pressurized water.
- Tracer wire
- A wire buried with plastic pipe so a locator can find it later.
- Trench box
- A steel shield placed in a trench to protect workers.
V
- Vacuum excavation
- Digging with air or water and a vacuum to expose buried lines without damaging them.
W
- Warning tape
- Colored tape buried above a line to warn future diggers.
- Wet well
- The underground chamber of a lift station where wastewater collects before it is pumped.
No terms match that search.
Call 811. Then call us.
Tell us what you are building, fixing or draining and we will suggest a site visit and a plan. The lines get located before the bucket moves.