Infrastructure and Utilities Installation Project Timeline

The Problem: Underground Infrastructure Is the Hidden Critical Path

On any new development site—residential subdivision, commercial park, or mixed-use district—the underground infrastructure must be installed before anything above grade can be built. Water mains, sanitary sewer, storm drainage, dry utilities (gas, electric, telecom), and road base are the foundation on which every building, street, and landscape element sits. They're also the part of a project that most frequently causes schedule delays.

Infrastructure installation is complex because it involves multiple independent utility providers (the water district, the gas company, the electric utility, and multiple telecom providers), each with their own permitting, design review, and inspection processes. You cannot install the electric conduit until the electric utility approves the design. You cannot install the gas main until the gas company approves and inspects. You cannot pour the street pavement until all underground utilities are installed and inspected. A single utility provider who takes 6 months to approve a design can hold up the entire site.

gantt-chart.io lets civil engineers and land developers build an infrastructure installation timeline that shows every utility's critical path—so you know in Month 1 which utility agreement will determine your construction start date.

Prerequisites

Before building your infrastructure installation timeline:

Site plan and utility layout: Approved or preliminary engineering drawings showing utility routes
Utility jurisdiction contacts: Water district, sewer authority, gas company, electric utility, telecom providers
Permit requirements: Grading permit, utility permits, right-of-way permits, NPDES
Soil conditions: Geotechnical report; rock, expansive clay, or high groundwater affect installation cost and schedule
Existing utilities: Any overhead utilities to be buried; any existing infrastructure to be relocated
Phasing plan: Whether infrastructure will be installed in phases or all at once
General contractor: Utility contractor selection for underground work
Inspection agencies: Which agencies inspect each utility type; scheduling lead times

Step-by-Step Instructions

Step 1: Set Up the Infrastructure Timeline

Open gantt-chart.io
Title it "[Project Name] — Infrastructure Installation — [Site Acreage] Acres"
For a 50-100 acre residential development, set the view to cover 18-36 months
Use Month view for permitting phases; Week view once construction starts
Add Infrastructure Acceptance / Final Inspection as the red milestone. Add Grading Permit Issued, Water Service Agreement, and Electric Service Agreement as orange milestones.

Step 2: Permitting and Utility Agreements

Create a task group: Permits & Utility Agreements
Add:

Grading permit application — submit after final engineering; 2-6 weeks review
NPDES / stormwater permit — 2-6 months; submit concurrent with grading permit
Water service agreement application — 3-9 months; utility board approval often required
Sewer service agreement application — 3-9 months; concurrent with water
Electric service agreement (PG&E, Xcel, local utility) — 3-12 months; design, capacity, and cost allocation
Gas service agreement — 2-6 months
Telecom conduit design approvals (AT&T, Comcast, fiber) — 2-6 months each
Right-of-way permits (county / city) — 2-6 weeks; for any work in public ROW
All permits and agreements in hand — milestone

Step 3: Grading and Earthwork

Create a task group: Grading & Earthwork
Add:

Clearing and grubbing — 2-6 weeks; remove vegetation, trees, structures
Rough grading / mass earthwork — 4-16 weeks; cut and fill to design grades
Subgrade preparation for streets — 2-4 weeks
Detention / retention basin excavation — 2-6 weeks
Rough grading complete and inspected — milestone

Underground utilities cannot be installed until rough grading is complete in each area.

Step 4: Wet Utilities (Water, Sewer, Storm)

Create a task group: Wet Utilities
Add:

Water main installation — 4-12 weeks depending on pipe length and size
Water main pressure test and disinfection — 1-2 weeks; health department inspection
Sanitary sewer main installation — 4-12 weeks
Sanitary sewer TV inspection — 1-2 weeks; camera inspection of every pipe segment
Storm drainage / detention outlet structures — 4-10 weeks
Storm sewer installation — 4-10 weeks; can run concurrent with sanitary
Wet utilities inspections and acceptance — milestone

Install wet utilities before dry utilities—trenches for water and sewer are deeper and wider; backfilling them first simplifies dry utility installation.

Step 5: Dry Utilities (Gas, Electric, Telecom)

Create a task group: Dry Utilities
Add:

Gas main installation — 2-6 weeks; gas company inspects and accepts
Electric conduit installation (developer-installed) — 2-6 weeks
Electric utility installation (utility-installed) — 4-12 weeks; utility sets its own schedule; coordinate closely
Electric transformer pads and vaults — 1-2 weeks
Telecom conduit installation — 2-6 weeks; multiple providers may install simultaneously
Fiber optic conduit — 1-3 weeks; if separate from standard telecom
Street lighting conduit and foundations — 1-3 weeks
Dry utilities inspections and acceptance — milestone

Step 6: Street Paving and Final Improvements

Create a task group: Paving & Final Improvements
Add:

Aggregate base compaction (road base) — 2-4 weeks; must pass compaction tests
Curb and gutter installation — 2-6 weeks
Sidewalk installation — 2-4 weeks; can run concurrent with curb
Street light fixture installation — 1-2 weeks; after conduit and pole base
Asphalt paving — base course — 1-3 weeks
Utility service connections to individual lots — 2-6 weeks; water meters, sewer laterals
Asphalt paving — finish course — 1-2 weeks; often deferred until builder construction traffic is complete
Signage and striping — 1 week
Final infrastructure inspection and acceptance — milestone

Key Milestones

Milestone	Typical Timing
Grading permit issued	Month 3-8
Water service agreement executed	Month 6-15
Electric service agreement executed	Month 6-18
Grading complete	Month 8-20
Water main accepted	Month 12-24
Sewer main accepted	Month 12-24
Dry utilities complete	Month 14-28
Paving complete	Month 18-32
Infrastructure acceptance	Month 20-36

Common Mistakes

Not starting utility agreement applications on Day 1: Electric and water utility agreements are almost always the long pole in the tent. Start these applications the day you close on the land. Do not wait for final engineering to be complete.
Installing dry utilities before wet utilities are accepted: Installing electric conduit in the same trench corridor as water or sewer that hasn't been accepted forces re-excavation if the wet utility fails inspection. Install and accept wet utilities first.
Not coordinating utility company design review timelines: The electric utility's design review process is internal and independent of the developer. If the utility takes 6 months to review and approve the design, you can't install the conduit until month 6. Track these reviews as explicit tasks with expected completion dates.
Paving too early: If builders will be running heavy equipment across streets during home construction, the finish course of asphalt will be damaged. Install the base course early; defer the finish course until builder construction is nearly complete.
Missing the NPDES permit timeline: NPDES (stormwater) permits for construction sites take 2-6 months in many states. Without this permit, you cannot begin grading. Submit the application concurrent with the grading permit.

Template

gantt-chart.io includes an infrastructure and utilities installation timeline template with permitting, grading, wet utilities, dry utilities, and paving tracks pre-loaded. Open it, adjust for your specific site acreage and utility jurisdiction review times, and share with your civil engineer and utility contractor.