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.

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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

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Step-by-Step Instructions

Step 1: Set Up the Infrastructure Timeline

1. Open gantt-chart.io
2. Title it "[Project Name] — Infrastructure Installation — [Site Acreage] Acres"
3. For a 50-100 acre residential development, set the view to cover 18-36 months
4. Use Month view for permitting phases; Week view once construction starts
5. 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

1. Create a task group: Permits & Utility Agreements
2. 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

1. Create a task group: Grading & Earthwork
2. 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

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

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

1. Create a task group: Wet Utilities
2. 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

1. 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)

1. Create a task group: Dry Utilities
2. 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

1. Create a task group: Paving & Final Improvements
2. 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

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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 |

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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.

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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.