ADU Builder in Temecula

Trust Company is the leading ADU Builder Temecula. Accessory dwelling units (ADUs) are a great way to add value to your property and provide additional housing options. If you are considering building an ADU on your property, be sure to contact Trust Company for a free consultation. We are a licensed and experienced contractor that specializes in building ADUs. We will work with you to design and build the perfect ADU for your needs and budget.

Types of ADUs

You don’t have to limit yourself to just one type of structure to add to your property! ADUs can come in different forms that can either be attached to or detached from your home.

This is the most common type that you’ll see on homeowners’ properties. It can be built in your backyard or property. Detached ADUs provide extra living space without the need to move. Some homeowners will rent out their detached ADUs for extra income while providing tenants with extra privacy.


As the name suggests, these ADUs are attached to your main home. These can be converted from existing space in your home, such as basements, extra rooms, and attics. These can also be called conversion ADUs.

By definition, a Junior ADU measures no more than 500 square feet. They’re a great way to add extra space to your home if you don’t want to spend the amount of a traditional detached ADU.

Trust Company Has Your Back

Trust Company is committed to providing you with an incredible experience throughout the ADU building process. Whatever your needs are for this extra living space, we will work with you to craft the perfect space.

We understand that local laws and regulations can be complex, so we are here to help you navigate the process to avoid constant headaches. The City of Temecula now also offers a pre-built ADU program to save homeowners like you time spent in the planning process!

An ADU can be a great way to add value to your home. Contact us at Trust Company the leading ADU Builder in Temecula.

ADU Permitting Process and Timeline

Typically contractors would not share this information with but that’s what makes us different. We are not your typical contractor and want to be as transparent and upfront with all our potential clients and current clients. 

Clients will be notified of every step in the process. 

  • Week 1   Contract signatures with deposit. We will perform a complete site and city analysis to confirm precisely what will be required to obtain a building permit. Design meeting to review customer’s dream ADU and discuss the project. 

  • Week 2-3  Review response from jurisdiction. Determine what is required of project. Start schematic design and scheduling needed consultants. The client is notified and provided pricing for consultants. Contracts signed and sent to consultants with deposits. 

  • Week 3-4  Review consultants reports and determine next steps to reach approval and permit.

  • Week 4-6  Meeting with client to review schematic design for approval. Update client on consultants and completed reports. 

  • Week 6-7  Final drawings completed and sent out to structural, mechanical, electrical and plumbing engineering.  

  • Week 7-9  Review structural drawings and value engineer. 

  • Week 9-12  Final reviews of plan set and completion of paperwork to be submitted to jurisdiction. 

  • Week 12-20  Constant contact with jurisdiction to push plans through permitting process. 

Additional Costs

*Plans, engineering, and consultants that may be required to obtain building permit and the typical investment. Varies according to size of structure and areas disturbed by construction.

Items Always Needed
  • Building design and drawings-$5,000-13,000
  • Structural engineer-$2,000
  • Electrical, mechanical, and plumbing engineering-$2,000-4,000
Sometimes needed (at jurisdictions discretion)
  • Topographical survey and boundary survey-$2,500-5,000
  • Soils Report–$2,500-3,500
  • Precise grading and drainage plan-$2,500-7,500
  • Water quality management plan-$7,500-1,500
  • Solar Design-$500-$1,000
  • Title report on the property-$100-350
  • Fire sprinkler design-$1,000-2,000
  • Truss calculation-$1,000-2,000

There will be other soft costs such as plan check fees, and permit fees.


Schematic design is a rough construction drawing that offers a general overview of a project’s basic features and construction.

A topographic survey locates all surface features of a property and depicts all natural features and elevations. In essence it is a 3-dimensional map of a 3-dimensional property showing all natural and man-made features and improvements. Specifically, it shows their location, size, height, and any changes in elevation.

This provides property boundary and easement information. 

A Soil Report is an official document issued by independent geotechnical engineers and engineering geologists which assesses the properties of your soil.

Precise grading and drainage plan is a detailed map or drawing that outlines the intended contouring and sloping of a construction site. The plan considers the natural topography of the site and any man-made structures, such as buildings or roads, to ensure that rainwater and other surface water are properly diverted away from structures and into appropriate drainage systems.

Building design and drawings refer to the process of designing a structure, such as a building, and creating detailed plans and illustrations that communicate the design intent and technical specifications to contractors, builders, and other stakeholders. The design process involves a range of considerations, including the functionality of the building, aesthetics, safety, and compliance with building codes and regulations.

Structural engineering typically involves analyzing the loads that a structure will need to bear, such as the weight of the building itself, the weight of furniture and people, and the forces of wind and earthquakes. It involves the design of structural elements of a building, including the foundation, walls, floors, and roof, and ensure that they are integrated seamlessly into the overall design.

Electrical engineering involves the design, installation, and maintenance of electrical systems within a building. This includes the wiring, lighting, power distribution, and communication systems. Electrical engineers ensure that these systems are safe, efficient, and reliable, and comply with applicable codes and standards.

Mechanical engineering involves the design, installation, and maintenance of mechanical systems within a building. This includes heating, ventilation, and air conditioning (HVAC) systems. Mechanical engineers ensure that these systems efficient and comply with applicable codes and standards.

Plumbing engineering involves the design, installation, and maintenance of plumbing systems within a building. This includes the piping systems for water supply, waste disposal, and gas supply. Plumbing engineers ensure that these systems efficient and comply with applicable codes and standards.

A Water Quality Management Plan (WQMP) is a comprehensive strategy for managing water quality within a specific geographic area, such as a watershed or a community. The goal of a WQMP is to protect and improve water quality by reducing or eliminating pollutants and other harmful contaminants.

Solar design refers to the process of designing and integrating solar energy systems into a building or infrastructure. The goal of solar design is to maximize the use of solar energy and minimize the reliance on non-renewable energy sources such as fossil fuels.

Fire sprinkler design refers to the process of designing and integrating fire sprinkler systems into buildings or other structures. The goal of fire sprinkler design is to provide effective fire protection and minimize the risk of property damage, injury, or loss of life in the event of a fire.

Truss calculation refers to the process of determining the load-bearing capacity and structural integrity of structural elements making up a prefabricated ceiling and roof frame system.

Value engineering can be defined as an organized effort directed at analyzing designed building features, systems, equipment, and material selections for the purpose of achieving essential functions at the lowest life cycle cost consistent with required performance, quality, reliability, and safety.

Let’s Get Started

Ready to get started on the home remodel of your dreams? Contact a general contractor at Trust Company at 951-760-9968 or fill out our project form today!