Every developer and project manager needs a cost estimate before detailed design is complete. The budget must be set, the proforma must be run, and the lender must be satisfied — all before the civil engineer has produced a construction-ready plan set with detailed quantities. This is where rules of thumb come in. They are not substitutes for a detailed estimate, but they get you to a realistic budget number during feasibility and schematic design.

The Major Civil Cost Categories

Category	Typical Range (% of total civil)
Earthwork (grading, import/export)	15-35%
Paving (AC, concrete, base)	20-30%
Storm drain and stormwater BMPs	15-25%
Wet utilities (water, sewer)	10-20%
Dry utilities (electric, gas, telecom conduit)	10-20%
Retaining walls	0-15% (if applicable)
Landscaping and irrigation	5-15%

Unit Costs (2025-2026 Range)

These costs are rough-order-of-magnitude for mid-range markets (not Manhattan, not rural Wyoming). Adjust up 10 to 30 percent for high-cost urban markets (Bay Area, Portland metro, Hawaii) and down 10 to 20 percent for lower-cost markets.

Earthwork

Item	Unit	Cost Range
Mass grading (on-site cut and fill)	CY	$5-15
Soil import (delivered and placed)	CY	$15-35
Soil export (load, haul, dispose)	CY	$20-45
Over-excavation and recompaction	CY	$12-25
Rock excavation (rippable)	CY	$25-50
Rock excavation (blasting/hoe-ramming)	CY	$50-120

Paving

Item	Unit	Cost Range
Asphalt concrete (3" AC over 8" AB)	SF	$4-8
Concrete pavement (6" PCC over 4" AB)	SF	$8-14
Concrete sidewalk (4")	SF	$8-14
Curb and gutter (barrier)	LF	$25-45
Curb and gutter (rolled)	LF	$20-35
Striping	Stall	$30-60

Utilities

Item	Unit	Cost Range
Storm drain pipe (18" RCP)	LF	$80-150
Storm drain pipe (24" RCP)	LF	$100-180
Storm drain manhole (48")	EA	$5,000-10,000
Catch basin / inlet	EA	$3,000-7,000
Water main (8" DIP)	LF	$80-150
Fire hydrant (complete)	EA	$5,000-10,000
Sewer main (8" PVC)	LF	$70-130
Sewer manhole (48")	EA	$5,000-10,000
Joint trench (electric + telecom)	LF	$50-100

Stormwater BMPs

Item	Unit	Cost Range
Bioretention basin	SF of basin	$15-35
Underground detention vault (precast)	CF of storage	$20-40
Underground chambers (StormTech)	CF of storage	$12-22
Pervious pavement (premium over conventional)	SF	$4-12

Retaining Walls

Item	Unit	Cost Range
Gravity block wall (up to 4')	SF of face	$25-50
Cantilever concrete wall (4-10')	SF of face	$45-90
MSE wall	SF of face	$30-60
Soldier pile and lagging	SF of face	$55-130

Rules of Thumb for Total Civil Cost

When you need a ballpark number before any design has been done:

• Commercial (flat site, no retaining walls): $15 to $30 per SF of site area
• Commercial (moderate grading, some walls): $25 to $50 per SF of site area
• Residential subdivision (per lot, including streets): $30,000 to $80,000 per lot
• Hillside development: $40 to $80+ per SF of site area (highly variable based on terrain)
• School campus: $20 to $40 per SF of site area (extensive accessible routes and drainage)

These are construction costs only — they do not include design fees (typically 5 to 10 percent of construction cost for civil engineering), permit fees, or utility connection and impact fees.

What Blows Up the Estimate

• Soil conditions. Expansive clay, high groundwater, contaminated soil, or rock — each can double or triple specific line items.
• Utility main extensions. If the nearest water or sewer main is 500 feet away, the extension cost can add $100,000+ to the budget.
• Retaining walls. On hillside sites, retaining walls can be 20 to 40 percent of the total civil budget.
• Off-site improvements. Traffic signals, street widening, and utility upsizing required as conditions of approval are often the most expensive items in the civil budget and the least expected.

Get the geotechnical report and the conditions of approval before you finalize the budget. Without those, even a detailed estimate is based on assumptions that may be wrong by a factor of two.