Drilling & boring
Sewer line directional drilling
Sewer is the one utility where slope matters, so the method is chosen by whether the line flows by gravity or by pump. Here is how new sewer gets installed without a trench.
Pressure sewer and force mains
A force main carries sewage under pressure from a lift station, and a pressure-sewer system does the same from grinder pumps at each property. Neither needs a slope, so both are routine directional-drilling jobs: HDPE or fusible PVC pulled in from 2 inches for a grinder-pump service to 24 inches and larger for a trunk force main, under roads, creeks and developed property. Most new sewer installed by HDD in the United States is one of these two.
Gravity sewer
Gravity sewer must fall continuously at the design slope, often half a percent or less, with no bellies. A directional bore follows a curve by nature and is tracked to within a few inches, so for short gravity runs with adequate slope an experienced crew can hold grade. For highway and railroad crossings, and anywhere the slope is shallow or the inspector requires it, the standard is an auger bore with a steel casing set on exact line and grade and the sewer pipe installed inside it on spacers. Pilot-tube microtunneling is used where grade is critical over longer distances.
Laterals and services
New sewer laterals from a house or building to the main are bored where the route crosses a driveway, a slab, a retaining wall or mature trees. Pressure laterals to a grinder pump are straightforward. Gravity laterals are bored at a steeper slope than the minimum so steering tolerance does not create a low spot, and they are inspected before connection.
Permits and inspection
Sewer is owned by a utility or a municipality that has standards for pipe material, depth, grade, testing and the casing it requires at crossings. The drilling contractor builds to those standards; the owner inspects and often videos the line before acceptance. State DOT and railroad permits apply at crossings.
Contractors by area
Sewer drilling contractors are listed here by state and city. In the Southeast the listed contractor is Davis Underground Solutions, which bores force mains, pressure sewer and cased crossings across the region. Elsewhere, the national line routes your project to a contractor working your area. Estimates are free.
Estimates are free. Call now: (855) 804-1434 — or pick your state below to reach the contractor covering your area.
Find a sewer line drilling contractor by state
Other drilling and boring services
Directional Drilling
Horizontal directional drilling (HDD) for new underground utilities: steered bores under roads, driveways, parking lots, creeks and landscaping with no open trench.
Horizontal Boring
Horizontal boring for conduit, casing and carrier pipe where digging across a surface is not an option.
Auger Boring
Steel-cased auger bores for road, rail and railroad crossings that need a straight, on-grade casing.
Pipe Boring
Boring and pulling in HDPE or steel product pipe from a few inches up to large-diameter casings.
Fiber Optic Drilling
Directional drilling for fiber and communications duct: long bores, multiple ducts in one pull, tight easements.
Electrical Conduit Drilling
Bores for primary and secondary power conduit, lighting circuits and site electrical feeds.
Utility Drilling
Multi-utility installs for developers and utilities: power, gas, water, sewer and telecom on one site plan.
Water Main Drilling
HDD installation of new water mains and service lines, including creek and road crossings.
Gas Line Drilling
Bores for new natural gas mains and services, coordinated with the utility and its operator-qualification rules.
Questions about sewer line drilling
Can gravity sewer be installed by directional drilling?+
On short runs with adequate slope, yes, by an experienced crew with close tracking. Where grade is critical or the crossing owner requires it, a cased auger bore or pilot-tube method is used instead.
What is a force main and why is it easy to bore?+
A force main is a pressurized sewer line fed by a pump station. Because it flows under pressure it has no slope requirement, so it can follow the curve of a directional bore like a water main.
What pipe is used for bored sewer lines?+
HDPE for most force mains, pressure sewer and laterals; fusible PVC where the utility specifies it. Gravity sewer in a casing is usually PVC or ductile iron on spacers.
How is a bored sewer line tested?+
The owner's standard governs: pressure test for force mains, low-pressure air or mandrel and video for gravity lines, and a deflection test on larger pipe. The contractor should include testing in the quote.
Can a new sewer line be bored under my driveway or slab?+
Yes. Pressure laterals are routine; gravity laterals are bored at a slope steep enough to absorb steering tolerance and are inspected before they are connected to the main.