Class A Licensed Civil Contractor · Diamond Bar, California
Civil & Infrastructure
in Diamond Bar, CA
TDQ Construction handles the civil infrastructure work most contractors in Diamond Bar cannot legally self-perform — sewer laterals, utility connections, site grading, drainage, and concrete. Class A General Engineering licensed since 1987.
Class A — What It Means
Civil Work Most Contractors Cannot Legally Do
California's contractor licensing system separates civil construction from general building. Sewer lateral replacement, utility connections, and major site grading legally require a Class A General Engineering Contractor license — a license the majority of residential and commercial building contractors do not hold.
TDQ Construction has held a Class A license since our founding in 1987. Combined with our C-8 Concrete Contractor license, we can perform every phase of civil infrastructure work in Diamond Bar in-house — without splitting your project between multiple licensed specialty firms.
We serve Diamond Bar including The Country, Pantera, Maple Hill and all surrounding areas.
Services
Civil Infrastructure Services in Diamond Bar
Sewer Lateral Replacement
Inspection, repair, and full replacement of private sewer laterals in Diamond Bar — from structure to public main — including trenchless lining and open-cut replacement.
Class A licensed scopeUtility Connections & Tie-Ins
New water, sewer, and gas service connections for ADUs, additions, and new structures in Diamond Bar — coordinated directly with local utilities under our Class A license.
All utility typesSite Grading & Earthwork
Precise grading for drainage compliance, building pads, driveways, and sloped lot development throughout Diamond Bar — engineered for long-term stability.
Engineered grading plansDrainage Systems
French drains, catch basins, area drains, and surface swales for Diamond Bar properties — designed to manage water flow away from structures and meet local drainage requirements.
Surface & subsurfaceConcrete Flatwork
Driveways, walkways, patios, parking areas, and slabs in Diamond Bar — formed, poured, and finished under our C-8 Concrete Contractor license.
C-8 licensedDemolition & Site Prep
Selective and full demolition, pavement removal, and complete site clearing in Diamond Bar — including haul-away and rough grading to building pad elevation.
Full site clearingWhy Choose TDQ
The Civil Contractor Other Contractors Refer
When residential and commercial contractors in Diamond Bar encounter civil scope they cannot legally self-perform, they refer to Class A firms like TDQ. Our civil licensing, field experience, and in-house concrete capability make us the qualified choice for infrastructure work that goes beyond what most builders are authorized to do.
Discuss Your Diamond Bar ProjectClass A — The Only License for Civil Work
Civil and infrastructure construction in Diamond Bar — sewer laterals, utility connections, grading — legally requires a Class A General Engineering Contractor license. This is not a license most building contractors hold. TDQ's Class A license authorizes us to perform all civil scope in-house.
C-8 Concrete In-House
Concrete flatwork, foundations, and retaining walls in Diamond Bar require a C-8 Concrete Contractor license to perform legally as a prime contractor. TDQ holds this license, meaning all concrete scope is self-performed — no specialty subcontractor required.
Utility Coordination Experience
Connecting new structures to Diamond Bar's utility infrastructure requires knowing how to work with local water districts, sewer agencies, and gas utilities. TDQ has decades of experience coordinating these connections — including service applications, inspection scheduling, and agency approvals.
The Civil Foundation of Every Project
Every ADU, addition, or remodel TDQ builds starts with proper civil infrastructure. Because we perform this scope in-house, our residential projects benefit from the same engineering discipline we bring to standalone civil work — no coordination gaps, no hand-offs.
How It Works
Assessment to Final Sign-Off
Site Assessment
We assess your Diamond Bar property, review existing utility connections, drainage conditions, and grading — and identify all civil scope required for your project.
Engineering & Permitting
Civil plans are prepared or coordinated with a licensed civil engineer, submitted to the Diamond Bar building department and relevant utility agencies for approval.
Utility Notifications
Underground Service Alert (USA/811) notifications are submitted and all existing utilities located before any excavation begins.
Excavation & Civil Work
Grading, trenching, sewer lateral work, utility connections, and drainage installation performed in the correct sequence with required safety measures.
Inspections
All civil work is inspected at required stages — trench inspections, utility connection inspections, and grading certifications as required.
Backfill, Compaction & Restoration
Trenches are backfilled and compacted to specification. Surface areas are restored — pavement, landscaping, or prepared as building pad.
Civil Work in Diamond Bar
Local Infrastructure Knowledge
Civil infrastructure work in Diamond Bar involves coordination with multiple agencies — the city building department, the local water district, the sewer authority, and utility providers. TDQ has decades of experience navigating these processes throughout California and understands how to move projects through local approval systems efficiently.
Diamond Bar sewer lateral requirements vary by property age and local ordinance. Some jurisdictions require lateral inspection or certification at time of sale, remodel permit, or ADU construction. TDQ stays current with local requirements and advises property owners accordingly before any work begins.
Drainage and grading requirements in Diamond Bar are governed by both local grading ordinances and California stormwater regulations. TDQ designs and installs drainage systems that meet current compliance standards — protecting both your property and the local watershed.
Areas We Serve in Diamond Bar
Civil Infrastructure Throughout Diamond Bar
TDQ Construction serves property owners across Diamond Bar including The Country, Pantera, Maple Hill and all surrounding areas.
Free Estimate
Start Your Diamond Bar Civil Project
TDQ provides detailed written estimates before any civil work begins — clear scope, timeline, and permit requirements for your Diamond Bar project.
Fastest response
(714) 357-1608
Teddykier@outlook.com
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