(209) 841-8226 · Office
CSLB #969791 · General A · Bonded · Insured
California • Lic #969791 • 12 Years Underground
Utilities. Septic. Dirt Work. Precision below the surface.

Licensed and bonded underground construction company serving California. Utilities, septic, excavation. Every aspect from start to finish, so you don't have to manage handoffs.

Call (209) 841-8226 Request a Quote
H2O-A01
Where We Work

Serving the
Central Valley.

Cal Underground is based in Waterford, CA, and runs underground construction across Stanislaus County and the wider Central Valley.

Service Area · 2026
Cal Underground service area across California's Central Valley

Cities & Towns Served

Headquartered in Waterford · Stanislaus County

Waterford
Modesto
Turlock
Oakdale
Ceres
Riverbank
Patterson
Hughson
Manteca
Stockton
Merced
Tracy
Outside the radius? Call anyway, bigger jobs travel.
SVC-04
What We Do

Underground
construction,
start to finish.

Whatever lives under the dirt, from pipe and conduit to septic and drainage, we install it, repair it, and dig around it. General A licensed, CA Public Works certified, and 12 years on jobsites means there isn't much we haven't seen.

01

Underground Utilities

Installation and maintenance of water, sewer, storm drain, electrical, and telecommunications infrastructure, from new construction tie-ins to emergency repair.

  • Water Mains & Service Lines
  • Sewer Lines & Storm Drains
  • Electrical & Telecom Conduit
  • Tie-Ins & Emergency Repair
02

Septic Systems

Comprehensive septic installation, repair, and maintenance for residential and commercial sites. Permitting, design, and execution as one continuous workflow, built to pass inspection on the first walkthrough.

  • New Installs & Leach Fields
  • Repairs & Maintenance
  • Permitting & Design
  • Residential & Commercial
03

Public Works

CA Public Works certified for prevailing-wage municipal and government projects. Permitting, compliance, inspections, and reporting. Every job, on the books, every time.

  • DIR #1001105862
  • Public Works #2044146
  • Prevailing Wage Compliant
  • Permitting & Inspections
04

Dirt Work

Site preparation done right the first time. Grading and excavation that meets engineering tolerances and stays on schedule. Clean cuts, accurate elevations, finished sites.

  • Grading & Excavation
  • Trenching & Backfilling
  • Site Prep & Pads
  • Residential & Commercial
SEC-07/TRUST
Why Hire Cal Underground

Licensed.
Bonded.
Zero
Complaints.

Anyone can hand you a quote. We hand you 12 years in the trade, a General A California license, a CLEAR record with the state license board, CA Public Works certification, and the bond and insurance to back every job we run.

12YRS
Proven Underground
Twelve years of underground construction. Utilities, septic, and dirt work, delivered on time, on budget, off your plate.
A
General A Licensed
California General Engineering Contractor. CSLB #969791. Active and in good standing since 2012.
0
CSLB Complaints
Clean record with the California Contractors State License Board. License status: CLEAR. Every job, on the books.
PW
Public Works Certified
Registered for prevailing-wage municipal and government work. DIR #1001105862 · Public Works #2044146.

Bonded & Insured

Fully bonded and insured through American Contractors Indemnity and State Compensation Insurance Fund. Project security on every job.

One Continuous Workflow

From permitting and design to execution and signoff. No handoffs, no surprises, no finger-pointing between subs.

Clean Sites, Every Time

Job sites left clean and tidy. Dirt put back. Yard restored. Inspector walks once and signs off.

Project Portfolio

Completed jobs,
on the record.

Photo · Take 5 Oil Change
Underground utility installation at Take 5 Oil Change, Modesto CA
01 / 07Modesto, CAAug 2025
Commercial · Underground Utilities

Take 5 Oil Change

Location Modesto, CACompleted Aug 2025

Full underground utility package for a new Take 5 Oil Change location: new domestic water service, sanitary sewer mains with cleanouts and tie-in to the existing main, and a complete storm drain system with manholes, catch basins, and area drains. Also built an underground StormTech detention and treatment system, delivering an engineered stormwater solution compliant with regulatory standards.

Domestic WaterSanitary SewerStorm DrainStormTech
Photo · Oakdale Shop Site Work
Water, electric, and septic installation for a new shop in Oakdale CA
02 / 07Oakdale, CAApr 2024
Residential · Site Work & Utilities

Oakdale Shop Site Work

Location Oakdale, CACompleted Apr 2024

Complete site services for a new shop build. Trenched and installed a new water line tied into existing infrastructure, ran a dedicated underground electric line to code, and installed a full septic system with tank and leach lines. Finished with grading for proper drainage around the shop. Completed on time and within budget, with a clean worksite throughout.

Water LineUnderground ElectricSeptic SystemGrading
Photo · Custom Home & Shop
Building pad grading and utilities for a custom home and shop in Modesto CA
03 / 07Modesto, CAJul 2023
Residential · Site Work

Custom Home & Shop Site Work

Location Modesto, CACompleted Jul 2023

Multi-phase site prep for a custom home and shop. Graded both building pads to the architect's specifications with proper elevation and compaction, then installed the full underground package: water lines, underground electric to local code, and a complete septic system with tank and leach field. Site cleaned and graded for drainage, ready for vertical construction.

Pad GradingWaterElectricSeptic
Photo · Oakdale Fairway 7
Aerobic septic system installation at Oakdale Fairway 7 for Tesoro Homes
04 / 07Oakdale, CAJul 2023
Custom Homes · Septic Systems

Oakdale Fairway 7 Septic

Location Oakdale, CAClient Tesoro HomesCompleted Jul 2023

Installed three aerobic septic systems for custom homes, each designed to site-specific conditions. Handled site evaluations and permits, excavation, and installation of tanks, aerators, and leach fields in full compliance with local regulations. Systems tested and calibrated, final inspections coordinated, and the job wrapped with zero disruption to the construction schedule.

3 Aerobic SystemsPermitsLeach FieldsInspections
Photo · East Oakdale Septic
Four aerobic septic systems for custom homes in East Oakdale CA
05 / 07East Oakdale, CAJun 2023
Custom Homes · Septic Systems

New Custom Home Septic Systems

Location East Oakdale, CACompleted Jun 2023

Four aerobic septic systems installed for new custom homes, each designed around site conditions and built to code: tanks, aerators, piping, and leach fields. Every system was tested, calibrated, and taken through final inspection. Homeowners were set up with maintenance guidance plus two years of warranty septic service, all with no disruption to the build schedule.

4 Aerobic Systems2-Yr WarrantyTesting & Calibration
Photo · Irrigation Pond Expansion
Irrigation pond expansion excavation in Waterford CA
06 / 07Waterford, CAJan 2022
Agricultural · Dirt Work

Irrigation Pond Expansion

Location Waterford, CACompleted Jan 2022

Expanded an existing irrigation pond to boost water storage for agricultural use. Controlled excavation enlarged the footprint and depth without disrupting the existing irrigation system, followed by grading and soil stabilization to prevent erosion. Finished by integrating the larger pond with the client's irrigation infrastructure and adjusting overflow and drainage for the added volume.

ExcavationGradingSoil StabilizationIrrigation Tie-In
Photo · Guest House Demolition
Guest house demolition and concrete removal in Tracy CA
07 / 07Tracy, CAJun 2021
Residential · Demolition

Guest House Demolition

Location Tracy, CACompleted Jun 2021

Demolished a guest house and removed all concrete foundations as part of a residential renovation. Utilities were safely disconnected, the structure was taken down with the main residence and landscape protected, and all concrete, walkways, and debris were hauled off site. The property was left clean and build-ready for the next phase of development.

DemolitionConcrete RemovalHaul-OffSite Restoration
01 / 07
How It Works

Five steps,
no surprises.

Hiring a utility contractor shouldn't feel like a gamble. Here's how the job actually runs from your first call to the moment we restore the dirt.

01

Call

You ring, we answer, or we call back fast. Quick conversation to size up the job.

02

Walk-Through

Free site visit. We look at the dirt, the access, the lines, the permits. You don't pay a dollar.

03

Quote

Written estimate with scope, materials, timing, and price. No fine print, no surprises.

04

Schedule

You sign off, we lock the date, pull permits, and call DigAlert. Crew shows up on time.

05

Dig & Restore

Work runs clean. Inspector signs off. Dirt goes back. Your yard looks like we were never there.

Got a Job?

Precision work, below the surface.

Utilities, septic, dirt work, public works. Whatever you've got going underground, we'll take a look. On time, on budget, off your plate.

Call (209) 841-8226 Request a Quote
CONTACT-01
Get In Touch

Let's talk about
your project.

Fastest way to reach us is the phone. If you'd rather write it out, the form below goes straight to the team.

Cal Underground

Your trusted
partner,
underground.

Licensed and bonded underground construction company based in Waterford, CA. Serving Stanislaus County and California's Central Valley. CSLB #969791 · General A · Public Works Certified.

Direct · CEO
Tyler Nichols · (209) 919-4845
tyler@calunderground.com
Estimating
(209) 841-8315
estimating@calunderground.com
Office
(209) 841-8226
admin@calunderground.com
License
CSLB #969791
Active · General A · DIR #1001105862
Request a Quote

Tell us about the job.

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