#1 ADU Contractor in Rialto
Custom Builds by Horizon Remodeling
Horizon Construction & Remodeling Inc. builds accessory dwelling units and room additions for homeowners across Rialto, handling design coordination, budgeting, material selection, and permit filing with the City of Rialto Building and Safety Division from start to finish. Most homes here are single-story postwar or late-century tract houses, and the age of the structure is usually what shapes the scope of work rather than any unusual local overlay. We coordinate every licensed trade involved so the finished unit meets current building code and fits the way you actually use your property.
Services We Offer
How Our ADU Process Works
When it comes to enhancing your living space, room additions combined with Accessory Dwelling Unit (ADU) construction offer unparalleled versatility and value. These projects not only increase square footage but also provide additional living accommodations, whether for extended family, rental income, or work-from-home setups, making them a popular choice for homeowners seeking to maximize their property’s potential. According to California’s Department of Housing and Community Development, ADUs are a key solution to expanding housing options in urban and suburban neighborhoods.
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Finding the right adu contractor in Rialto starts with understanding the rules that govern what you can build and where. California consolidated its ADU statutes into Government Code sections 66310 through 66342 in 2024, and those rules were updated again on January 1, 2026. Under the current law, square footage is calculated as interior livable space only. Once you submit an application, the agency has 15 business days to determine whether it is complete and 60 days to approve or deny it. Approval is ministerial, meaning no public hearing and no discretionary design review stands between you and a decision.
For Rialto properties, that application goes directly to the City of Rialto Building and Safety Division. No unusual local overlay applies here, so what governs your project is the state building code combined with the age and condition of the house itself. Many homes in the city were built in the postwar and late-century tract-building decades that followed the city’s 1911 incorporation as a small citrus community, and the building code treatment of those structures reflects that era of construction.
San Bernardino County adopted a new ADU chapter, Development Code Chapter 84.36, at the Board of Supervisors on January 13, 2026. Published county standards allow an ADU ranging from 200 to 1,200 square feet, a junior ADU up to 500 square feet, attached height up to 25 feet, and detached height up to 18 feet with two additional feet permitted to match an existing roof pitch. Side and rear setbacks are four feet, with five feet of separation required between detached structures. Two ADUs per lot are permitted, and properties of five acres or more may accommodate three units.
Sewer connection is often the question that determines whether a project is feasible. Connection is required when a sewer line runs within 200 feet of the property line, with that distance increasing by 100 feet for each additional dwelling unit. Where no sewer connection is required, the project relies on septic or an advanced treatment system. We involve Environmental Health early in the process, before plans are drawn, so that finding does not come as a surprise midway through design.
The lot itself shapes most remaining decisions. Rialto’s typical single-story postwar tract house, often with a galley or L-shaped kitchen separated from the family room by a wall, creates a specific set of conditions for where a detached unit can sit and how far utility runs need to extend. That layout is something we account for during the site review, well before any plans go to the City of Rialto Building and Safety Division for review.
Other Remodeling Services We Offer
A modern kitchen adds functionality, comfort, and lasting value to your home. At Horizon Construction & Remodeling, our kitchen remodeling experts bring fresh ideas and professional project management tailored to your unique needs. From layout design to material selection, we prioritize delivering a high-standard kitchen that’s both beautiful and energy-efficient — enhancing the way you cook, gather, and live every day.
Whether you envision a classic Southern California pool or a fully customized backyard oasis, Horizon Construction & Remodeling delivers the highest level of quality and service. Our comprehensive pool design and remodeling services cover everything from layout and decking to built-in BBQs and final touches like landscaping. Let Horizon be your trusted partner in transforming your backyard into the perfect outdoor retreat.
If you are planning a complete bathroom remodel or simply want to change your tub, shower, update your plumbing fixtures, or make the space more efficient, our team at Horizon will help you through the process with expert advice, professional craftsmanship, and affordable options with beautiful results. Learn more about our bathroom remodeling services.
Transform your space with our expert interior work services. We offer a comprehensive range of solutions — from space planning and custom design to the selection of high-quality finishes and materials. Our team of experienced professionals works closely with you to create a space that’s both functional and stylish, tailored to your unique needs, goals, and budget. Whether you’re updating a single room or overhauling your entire interior, we bring precision, creativity, and craftsmanship to every project.
At Horizon, we believe your home is more than just four walls — it’s where life happens. It’s the place you relax, gather with family and friends, and create lasting memories. That’s why we offer a full range of exterior work services designed to elevate your outdoor living space. From patios and hardscaping to custom decks and exterior renovations, we help turn your vision into a dream yard that complements your lifestyle and enhances curb appeal.
At Horizon Construction & Remodeling, our expert team includes a dedicated design and planning division that works hand-in-hand with licensed architects and structural engineers. We take care of everything — from detailed plans and blueprints to securing city permits — so you don’t have to deal with delays or red tape. Our goal is to streamline the process and provide a fully approved set of documents that aligns with both your vision and city regulations, saving you time and stress.
Why Choose Horizon Remodeling As Your ADU Contractor in Rialto ?
ADU Construction in Rialto Built Around Your Property and the Code That Governs It
Horizon Construction and Remodeling is a licensed Class B general building contractor, bonded and in business since 2009, and we handle ADU projects in Rialto from initial drawings through the final inspection at the City of Rialto Building and Safety Division. Because most homes here are postwar or late-century tract houses, the age of the structure and the base building code are what shape the project. No unusual local overlay complicates the process, which means the work is straightforward once the plans are right.
A single company drawing the plan, running the permit, and doing the build keeps the project from falling through the cracks between separate firms. Before design begins, we work through the feasibility questions first: sewer connection, access, and how the existing structure responds to adding a unit. Many Rialto homes were built as single-story tract houses, so we evaluate what the foundation and framing can support before anything goes on paper.
California state law provides important baseline protections regardless of where the parcel sits. No owner-occupancy requirement applies to an ADU, adding one does not trigger a sprinkler retrofit of the main house, and no impact fees apply to a unit with 750 square feet or less of interior livable space. We work throughout Rialto, including Downtown Rialto, North Rialto, Las Colinas, and El Rancho Verde.
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ADU Contractor Services in Rialto
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ADU Contractor in Rialto FAQ
What is an ADU and why should I build one?
An accessory dwelling unit is a self-contained secondary home built on your existing property, taking the form of a backyard cottage, a converted garage, or an in-law suite. Adding one in Rialto gives you options: rental income, a private space for family, or simply more room on a lot that likely holds a postwar tract house with room to grow.
How much does it cost to build an ADU in California?
What an ADU Actually Costs in Rialto
No contractor can quote you an honest number from a web page alone. The real cost depends on the size and type of unit you are building, whether you are converting existing space or putting up a new detached structure, what site work and utility runs your specific lot requires, and the finish level you choose. What we can tell you is where the money goes and what state law limits. Any ADU at or under 750 square feet of livable interior space is exempt from impact fees. School fees only apply once the unit exceeds 500 square feet. Connection fees for a conversion or junior ADU are capped, because state law does not classify those as a new residential use. Building an ADU also cannot force a fire sprinkler retrofit on your existing home.
Because most Rialto homes are postwar tract houses permitted and built under older standards, the age of the structure and current California building code are the two things that govern what your project requires once the City of Rialto Building and Safety Division reviews your plans. We walk the property, confirm the setback and utility situation, and then give you a fixed scope and price you can hold us to. One point worth stating plainly: the CalHFA ADU grant program is closed and fully allocated, and the agency itself warns that anyone offering to help you obtain that grant is running a scam.
Do I need permits for an ADU in Rialto?
Yes, every ADU requires a building permit, and in Rialto that application goes through the City of Rialto Building and Safety Division. State law sets the review timeline at 15 business days for a completeness determination and 60 days for an approval or denial, and the city’s process reflects those current state standards. Because most Rialto homes are postwar tract houses, the age of the structure and the base building code are typically what govern the review. If a property uses septic or a well, Environmental Health becomes part of the process, and any lot within 200 feet of a sewer line will need to connect. Horizon manages the submittal, corrections, and inspections from start to finish.
How long does ADU construction take with Horizon Remodeling?
Most ADU construction projects take between 4 to 8 months from design to completion, depending on scope and permit approvals. Horizon Remodeling prioritizes efficient timelines while maintaining quality workmanship.
What types of ADUs can Horizon Remodeling build?
We specialize in building detached ADUs, attached ADUs, garage conversions, backyard cottages, and junior ADUs (JADUs). Our team can help you choose the right ADU style for your property and goals.
Can I build a detached ADU on my property in Rialto?
Yes, if your property meets California zoning and space requirements. Horizon Remodeling will assess your site, secure the necessary permits, and build a fully detached ADU tailored to your preferences.
Is Horizon Remodeling licensed to build ADUs in my area?
Yes, Horizon Remodeling is fully licensed, bonded, and insured to build ADUs throughout Orange County and surrounding areas. We have over 18 years of experience delivering high-quality ADU projects.
What are the benefits of hiring Horizon Remodeling for my ADU project?
Horizon Construction & Remodeling Inc. handles ADU design, permitting through the City of Rialto Building and Safety Division, and construction from start to finish, coordinating every trade so your project meets current building codes and stays on budget.
Does Horizon Remodeling handle ADU design and permitting?
Absolutely! Horizon Remodeling provides complete ADU design services, including architectural plans and 3D renderings. We also handle city permits and inspections, streamlining your project and reducing stress.
How do I get started on an ADU with Horizon Remodeling?
Reach out to Horizon Construction and Remodeling to set up a free consultation, where we review your property, talk through your goals, and put together a detailed estimate with design recommendations so you know exactly what to expect as we guide you through every phase of your Rialto ADU project.
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Horizon is a licensed Class B general building contractor serving Rialto and the surrounding Orange County communities.
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