Directional Boring (HDD) Cost & Planning Calculator
Plan a horizontal directional bore: final reamer size from the product pipe, hole volume, drilling fluid, spoil to vacuum, rig days and an installed-cost estimate based on Florida DOT bid averages.
Directional Boring (HDD) Cost & Planning Calculator — ConcreteNear.com
| Bore hole volume | 441 gal |
| Drilling fluid to plan | 1,322 gal |
| Spoil + fluid to vacuum (approx.) | 8.7 yd³ |
| Rig days | 1.5 days |
Cost estimate U.S. average prices
| Conduit installed by directional bore 300 LF × $41.81 | $12,543 |
| Mobilization 1 job × $1,500 | $1,500 |
| Pits & potholes 4 each × $400.00 | $1,600 |
| Estimated total | $15,643 |
- Call 811 and pothole every crossing utility before you bore.
- Plan a vacuum truck for drilling-fluid returns — dumping slurry on site is often illegal.
| Inputs | |
| Bore length | 300 ft |
| Product pipe / bundle outside diameter | 4 in |
| Back-ream ratio | 1.5 |
| Ground | Clay / silt |
| Drilling fluid (× hole volume) | 3 |
| Production (ft per rig-day incl. pullback) | 400 ft |
| Pits & potholes | 4 |
Planning estimate only — confirm with your supplier or contractor.
Prices used — edit any price to match your local quote
| Item | Unit price | Basis & source |
|---|---|---|
| Conduit installed by directional bore per LF | public source Florida DOT Item Average Unit Cost 2025, item 0630 2 12 Conduit, Furnish & Install, Directional Bore (194 contracts, 708,221 LF) (2025 lettings) — Typical small-diameter traffic/ITS conduit. Same source: open-trench conduit averaged $18.04/LF. | |
| Bore rig mobilization per job | starting estimate Starting estimate. | |
| Entry/exit pit or pothole per each | starting estimate Starting estimate. |
How to use this calculator
- Enter bore length and product pipe or bundle OD.
- Keep a 1.5 ream ratio unless your plan says otherwise.
- Pick ground conditions and a fluid factor.
- Enter production and pits for rig days and cost.
Formulas
Reamer diameter = product OD × back-ream ratio (1.5 is a common rule)Hole volume (gal) = π × (reamer ÷ 2)² × length × 7.48Drilling fluid ≈ hole volume × fluid factor (commonly 3–5× in sand, more in clay)
Questions
What size reamer for HDD?
A common rule of thumb is 1.5 × the product pipe outside diameter (often +4 in for small pipe).
How much does directional boring cost per foot?
It varies by ground, pipe size and length. Florida DOT's 2025 statewide average for conduit furnished and installed by directional bore was $41.81 per foot (vs. $18.04 for open trench). Rock costs much more.
Where does the drilling mud go?
Returns are usually vacuumed and hauled to an approved site. Plan a vac truck.
Sources & assumptions
Prices checked 2026-11-10. State pricing multiplies national figures by the U.S. Bureau of Economic Analysis regional price parities (goods for materials, services for labor and services). RPPs compare general consumer price levels (U.S. = 100). They are not construction-specific; we use RPP Goods for materials and RPP Services: Other (excludes rents) for labor and services.
- Conduit installed by directional bore — Florida DOT Item Average Unit Cost 2025, item 0630 2 12 Conduit, Furnish & Install, Directional Bore (194 contracts, 708,221 LF) (2025 lettings). Typical small-diameter traffic/ITS conduit. Same source: open-trench conduit averaged $18.04/LF.
Starting estimates No public price series was found for: Bore rig mobilization; Entry/exit pit or pothole. These defaults are editable placeholders — replace them with a local quote.
Results are planning estimates, not quotes or engineering advice. Codes, specifications and your supplier's numbers govern.
Related calculators
Hydro-Excavation (Vacuum Truck) Calculator
Potholes and slot trenches by hydrovac: spoil volume, debris-tank loads, billable hours and cost.
Flowable Fill (CDF) Calculator
Yards of flowable fill / CLSM for trench backfill around pipe, pipe abandonment and void fill.
Work Zone Traffic Control & Flagging Calculator
MUTCD taper lengths, buffer space, sign spacing, cones and a flagger / traffic-control budget for your work zone.