Walnut is an upscale hillside suburb in the eastern San Gabriel Valley — larger homes on generous lots, many with hillside settings and views, in a community known for its schools and quiet residential character. The housing here trends toward substantial single-family homes: properties where renovations mean whole-home updates, kitchen expansions, primary suite additions, and outdoor living improvements. Hillside lots add their own considerations — longer sewer laterals, drainage-conscious planning, and HVAC systems working across multi-level floor plans. It’s a market where homeowners invest seriously in their properties, and where a multi-trade contractor who can handle the addition, the plumbing, and the HVAC under one contract is worth more than three separate bids.
Mars Construction Industries Corp is a multi-trade general contractor based in Orange, CA, operating with 30+ years of hands-on experience. We hold four CSLB licenses in-house — A General Engineering, B General Building, C-36 Plumbing, and C-20 HVAC (CSLB #1138550). One accountable team handles your construction, plumbing, drain and sewer work, and HVAC under a single contract.
Construction & Remodeling Services in Walnut, CA
Our Walnut work centers on substantial residential projects: whole-home remodels, kitchen expansions, primary suite additions, and room additions that give larger homes the space and flow their owners want. Because we hold C-36 plumbing and C-20 HVAC licenses in-house, an addition that needs new plumbing runs and resized climate control stays inside one project plan — sequenced properly, with one team responsible for how the new space connects to the existing home’s systems.
Hillside lots make infrastructure work worth doing well. We provide drain and sewer services — camera inspection, hydro jetting, trenchless sewer repair — with a 20-year warranty on our sewer lining. On hillside properties, where excavation is disruptive and laterals run long, trenchless rehabilitation protects the landscaping and delivers a renewed line. We also perform repipes, water heater replacements, and gas line work, pairing infrastructure renewal with remodels so walls open once.
ADUs fit Walnut’s larger lots well: through our sister brand ADU Cities, we’ve built more than 100 ADUs in four years, giving families independent space for relatives or long-term flexibility. And we install, replace, and repair HVAC systems — including multi-zone setups for larger, multi-level homes.
- Whole-home remodels and renovations
- Kitchen expansions and primary suite additions
- Room additions engineered for hillside lots
- ADUs — 100+ built in four years through ADU Cities
- Repipes, water heaters, and gas lines
- Drain and sewer services: camera inspection, hydro jetting, trenchless repair, sewer lining (20-year warranty)
- HVAC installation, replacement, and repair, including multi-zone systems
- Bathroom remodels
Why Walnut Property Owners Choose Mars
One accountable team is our model: A, B, C-36, and C-20 licenses in-house means your addition’s framing, plumbing, and HVAC are all performed by us under one contract. With 30+ years of hands-on experience, we’re licensed, bonded, and insured (CSLB #1138550), and we’re SB-PW and SB(Micro) certified. For a substantial home on a hillside lot, that single point of responsibility keeps complex projects coherent from estimate to final walkthrough. Our sister brands — 911 Drain Lines, ADU Cities, Get Your Roof Certified, and Universal Inspect — extend what one call covers.
Proudly Serving Walnut and Los Angeles County
Walnut is in the eastern San Gabriel Valley in Los Angeles County, within our service area. Our home base is at 1119 W. Collins Ave, Orange, CA 92867, and we serve the eastern SGV communities within roughly a 50-mile radius. Homeowners here get the same licensed, multi-trade team.
Frequently Asked Questions
Do I need a licensed contractor for my project?
In California, any construction project totaling $1,000 or more in labor and materials must be performed by a licensed contractor. Verify any license on the CSLB website before hiring. Ours is CSLB #1138550 — A General Engineering, B General Building, C-36 Plumbing, and C-20 HVAC.
How does your estimate process work?
We visit the property, walk through the project with you, and provide a written estimate. For additions and whole-home work, we scope construction, plumbing, and HVAC together so the number reflects the complete project.
Can you build an ADU on my lot?
Often, yes. We’ve built more than 100 ADUs in four years through our sister brand ADU Cities, and Walnut’s larger lots are a natural fit. We’ll evaluate your property and discuss the options.
Which trades do you handle in-house?
General construction and remodeling, plumbing, drain and sewer, and HVAC, all under our own licenses. Electrical work is performed by qualified licensed electricians we bring in, since we do not hold the C-10 electrical classification.
Do you handle plumbing or sewer emergencies?
Yes. Our sister brand 911 Drain Lines provides 24/7 drain and plumbing emergency service at 714.746.7611.
Get a Straight Answer on Your Project
From a kitchen expansion to an addition to an ADU, tell us what you’re planning and we’ll give you a straight answer. Call 310.880.9718 or email brett@marsx.construction. One accountable team, four licenses in-house, operating with 30+ years of hands-on experience.