Directional Drilling Cost Per Foot: The 2026 Guide
Key takeaways
- Typical range: directional drilling costs $14–$35 per linear foot for most small-to-mid-size bores in dirt, and $30–$60+ per foot on larger commercial work — large-diameter pipe can reach $120 per foot.
- Rock changes everything: bores in solid rock commonly run $70–$180+ per foot — ground conditions move the price more than any other factor.
- Pipe size matters: a 2-inch conduit bore and a 12-inch water main are different jobs with different rigs; bigger pipe = higher cost per foot.
- Short jobs carry a minimum: mobilization, locates, and setup are fixed costs, so a 60-foot bore costs far more per foot than a 600-foot bore.
- The honest answer is a range plus a site look. Any contractor who quotes a flat per-foot price sight-unseen is guessing with your money.
What is directional drilling?
Directional drilling — also called horizontal directional drilling (HDD) or directional boring — is a trenchless method of installing underground pipe, conduit, and cable along a guided path beneath the surface, without digging an open trench. A drill rig bores a pilot hole from an entry point, the hole is enlarged (reamed), and the product pipe is pulled back through. It is the standard way to get utilities under roads, railroads, rivers, driveways, and landscaped ground that cannot be torn up.
How these numbers were compiled (methodology)
The ranges on this page were compiled from published 2026 cost guides (including HomeGuide's directional boring cost data and DEVCO Development & Engineering's 2026 directional drilling cost guide), contractor-published pricing, and Four O Six Underground's own field experience on Montana jobs since 2013. Where sources disagreed, we published the wider range. These are budgeting ranges for planning, not a quote: your actual bid depends on the site visit, the ground, and what is already buried in the way.
Directional drilling cost per foot by bore type
| Bore type & ground | Typical cost per linear foot | Best suited for |
|---|---|---|
| 1–2″ conduit, dirt, open/rural ground | $14 – $28 | Fiber, telecom, and electrical conduit runs where nothing is in the way |
| 2–4″ pipe, dirt, in-town/urban | $15 – $35 | Water and sewer services, gas lines, conduit under streets and sidewalks |
| 4–6″ pipe, dirt | $20 – $45 | Commercial utility feeds, irrigation mains, multi-conduit bundles |
| 6–12″ pipe, dirt | $35 – $120 | Water mains, sewer mains, larger commercial and municipal work |
| Any size, rock | $70 – $180+ | Mountain and foothill ground; requires rock tooling and slower drilling |
| Road, highway, or railroad crossings | $35 – $80+ | Permitted crossings with casing, inspection, and traffic-control requirements |
For comparison, open trenching typically runs $5–$12 per foot for the digging alone — cheaper per foot where you are allowed to tear up the surface, and often more expensive in total once pavement, landscaping, and restoration are paid for.
Directional drilling vs. trenching vs. plowing: which is best suited for your job?
| Method | Cost picture | Best suited for | Watch out for |
|---|---|---|---|
| Directional drilling (HDD) | $14–$120/ft depending on size and ground — rock runs higher | Going under roads, railroads, rivers, driveways, and finished landscaping; deeper installs | Highest per-foot cost; needs room for the rig and entry/exit pits |
| Open trenching | $5–$12/ft digging, plus restoration | Open ground, new construction, shallow lines where the surface can be disturbed | Restoration (asphalt, concrete, lawn) can double the real total; weather delays |
| Vibratory plowing | Lowest per-foot cost on suitable ground | Long, shallow conduit and cable runs across open rural ground | Shallow depth only; rocks and roots stop it cold |
What drives the price up or down
- Ground conditions. Clean dirt is the cheapest drilling there is. Cobble, fractured rock, and solid rock slow the bore, eat tooling, and can double or triple the per-foot price.
- Pipe diameter and material. Bigger pipe needs a bigger rig, more reaming passes, and more drilling fluid. HDPE fusion or steel welding adds labor on top.
- Depth. Deeper bores (below other utilities, under waterways) take longer and carry more risk.
- Existing utilities. Congested corridors require potholing — vacuum-exposing each buried line in the path, typically $300–$500 per hole — before anyone drills.
- Permits and crossings. Railroad and highway crossings add permit fees, casing requirements, inspection, and traffic control.
- Restoration. If the job includes putting back asphalt, concrete, or landscaping, that is real money beyond the bore itself. Four O Six also runs a concrete division for flatwork restoration, which keeps that cost in one bid.
- Length. Per-foot pricing drops as footage rises, because mobilization and setup spread across more feet.
A worked example
Say a job needs 400 feet of 4-inch HDPE in decent dirt, including one road crossing. At a mid-range $25 per foot, the bore itself is about $10,000. Add two potholes to verify existing utilities (~$800), traffic control for the crossing day, and minor restoration, and a realistic planning budget lands around $11,500–$13,000. The same 400 feet in solid rock, at $70–$180+ per foot, would run several times that — which is why the site look matters more than the calculator.
Montana specifics most cost guides leave out
- Rock is normal here. Much of western and central Montana is cobble, fractured rock, or solid ledge within a few feet of the surface. National cost guides built on Midwest dirt will under-price Montana work.
- Locates run on a 30-day clock. Montana locate tickets are valid for 30 days from the work-to-begin date; long or delayed jobs need re-locates called in after 30 days. A good contractor builds that into the schedule instead of letting tickets lapse.
- Winter is a real factor. Frozen ground, drilling-fluid handling, and short days affect Montana schedules from roughly November through March. Booking shoulder-season work early is the cheapest scheduling move there is.
- Railroad crossings are their own project. Crossings under rail lines (BNSF covers much of Montana) carry permit lead times and casing rules that can drive the calendar more than the drilling does.
Frequently asked questions
How much does directional drilling cost per foot?
Most directional drilling costs $14–$35 per linear foot for small-to-mid-size bores in dirt, $30–$60 per foot for larger commercial and municipal work (large-diameter pipe can reach $120 per foot), and $70–$180+ per foot in solid rock. Pipe size, ground conditions, depth, and crossings are what move a specific job inside — or outside — those ranges.
Why won't contractors just give a flat per-foot price?
Because the ground decides the price. Two identical 300-foot bores can differ by 3x in cost if one is clean dirt and the other is solid rock with three utilities to pothole. A flat sight-unseen price means the contractor is either padding heavily or planning to renegotiate mid-job.
Is directional drilling cheaper than trenching?
Per foot of digging, no — trenching is cheaper. Per finished job, often yes: HDD avoids tearing up and restoring roads, driveways, sidewalks, and landscaping, and it is frequently the only legal option under railroads, highways, and waterways.
What is the minimum charge for a small bore?
Expect a minimum mobilization charge on short bores. The rig, crew, locates, and setup cost the same whether the bore is 60 feet or 300, so very short jobs price as a lump sum rather than a true per-foot rate. Ask for the minimum up front when you call.
How long does a directional drilling job take?
A typical single bore is drilled in a day or less once locates are cleared and the site is set up. Multi-bore projects and permitted crossings (railroad, highway) run longer — mostly because of permit and locate lead times, not drilling speed.
Do I need locates or permits before drilling?
Yes. Underground utilities must be located through Montana 811 before any drilling, and crossings under roads, railroads, and waterways need the relevant permits. A legitimate contractor will not drill without locates — and in Montana those tickets are valid for 30 days, so timing matters.
Can directional drilling go through rock?
Yes, with rock tooling (mud motors, rock bits, and reamers) — it is slower and harder on equipment, which is why rock bores sit at the top of the price range. An experienced crew will tell you honestly whether your ground is drillable or better served another way.
Call (406) 521-0015 · Email beau@406ug.com · Four O Six Underground — Helena, Montana
Four O Six Underground · Helena, Montana · Directional drilling & HDD consulting · (406) 521-0015 · beau@406ug.com. Cost ranges on this page are 2026 ranges for budgeting, checked against Four O Six's own job pricing; every job is bid on its own site conditions.
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