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It is recommended that Clients read the: CALIFORNIA DEPARTMENT OF HOUSING AND COMMUNITY DEVELOPMENT ACCESSORY DWELLING UNIT HANDBOOK UPDATED JULY 2022 available on-line. This handbook provides plenty of information on the various types of ADU’s,regulations related to their construction, along with the most recent legislation encouraging the building of Accessory Dwelling Units (ADU’s)].

What You Can Expect From JML

At JML Construction Services, we take pride in providing our clients with exceptional custom home building services. With years of experience dealing with the permitting process, including compliance with zoning and building code requirements related to ADUs, we are confident in our ability to guide our clients through the process from start to finish. We work closely with our clients to define the scope and cost of the ADU, spending the time necessary upfront to explore all options including size, cost, and location, so that our clients have a full understanding of what is involved before any project begins.


ADU Designs

Initial Screening 


Our goal is to provide guidance to the Client through the entire process of
designing and constructing an ADU making sure all aspects are discussed. To meet this objective, JML will work with the Client to quickly establish a high level scope and budget requirements based on the Client’s input. The intention is to determine if the client’s expected budget is realistic and the space allocated for the ADU will work. Included in this conversation will be the intended use of the ADU: will it be rented out or used for overflow of family members? This decision will drive some of the cost below. The “phases” allows the Client the options of “off-ramps” to minimize their out of pocket costs if they decide the project is either too expensive or does not meet their needs.

What are the things that influence the price of an ADU?

The cost of an ADU is influenced by a number of aspects. The typical range of ADU’s in this area can range from a low of $200/SF to over $800/SF depending on: o Does the Client have architectural plans or are they planning on using pre-approved ADU plans from their location municipality (not yet available in all towns)? Architectural fees can influence the cost/SF. o Materials selected. There is a wide variation of the cost of materials especially on countertops, flooring, appliances, windows and doors, roofing, and other interior finishes. We refer to this as the “fit & finish”. o Access to the site. Can we get large equipment on to the site for construction and delivery of materials or will we have to perform a lot of the work with hand labor? o What are the site conditions? Is it flat or will it need to be leveled, especially if the site is on the side of a hill with a significant slope? o Is the site very close to the property boundaries limiting the area we will be working in? o How far is the site rom the utility connections? o Will the Client assume doing some of the work themselves such as interior/exterior painting, purchasing and flooring, purchasing and arranging the delivery/installation of appliances ? This can be very effective in reducing the overall cost. o Note that when evaluating the cost of an ADU some costs are fixed regardless of size and some are variable. Square footage is variable but utility connection costs are fixed for the most part.

Scope Development


ADU’s are no different than the construction of a normal house with some
exceptions regarding zoning and approvals. It will need connections to utility
services (water, sewage, electricity, gas, cable). The ADU will need to meet all
state and local construction and energy code requirements. It also needs to
adhere to the local zoning requirements (which have recently been relaxed to
encourage ADU construction). This includes setbacks from property boundaries
and distances to other structures on the property. Phase 2 of scope
development would include JML doing the following:

- Develop a scaled dimensional plot plan of the property with the proposed ADU location and size shown. JML will take field measurements and determine if the necessary setbacks are available and show on the plot plan. This drawing would then be reviewed with local zoning officials to confirm the location and positioning of the proposed ADU’s meets all of the local zoning requirements. If required, JML will arrange to have the property surveyed to verify that the assumed property lines are in fact accurate (some property owners assume that their fences are installed on the property line when in fact they could either be encroaching on their neighbor’s property or their neighbors are encroaching on the property with the new ADU). - Determine the connection point of the sewage system (connect to the house or directly to the service in the street? Separate connections are more expensive than connecting to the main house system). Elevations will be checked to determine if there is sufficient pitch for the sewage to flow normally . If not a pumped system will have to be installed. JML will also obtain the connection fees. With our plumbing contractor we will provide the Client with the connection costs (which will include trenching to the ADU location). - Issues for electrical service result from many older homes have insufficient capacity to power an ADU and the service needs to be upgraded including installing solar ready components. Note that solar may also be required depending on the total energy consumption of all of the buildings on the property. With our electrical contractor we will provide the Client with the connection costs (which include trenching to the ADU location) - The potable water supply to the house Development Phase 3 will be inspected to determine if size is sufficient to supply the ADU. With our plumbing contractor we will provide the Client with the connections costs (which will include trenching to the ADU) - JML will determine the optimal path for all utilities to minimize excavation and connections costs (including using just one common trench for all lines if possible). - JML will research to determine if there are any easements on the property including overhead lines. JML will arrange an underground utility inspection to see if there are any utilities crossing the property. An inspection of the area will also include looking for underground obstructions not highlighted by the inspection such as abandoned/active (or active) septic systems and abandoned/active wells. - JML will determine additional fees for CCC Fire, school district fees, address assignment fees, and any other fees not normally included in the town building permit fee but all of which contribute to the overall total cost of the ADU. - JML will work with the Client on options to insure the project during construction. - JML will cost out the construction of the ADU including foundation and all of the utility and fee costs above assuming a realistic cost/SF based on the scope developed to date. This is meant to be a “screening” estimate so the Client can decide if it still meets their budget and we can proceed with developing a much more detailed scope of work and a fixed price final cost.


Phase 3 builds on the work done in the previous phases 1 & 2. JML will meet
with the Client and develop a very detailed scope of work. We will work through:

- All of the interior and exterior finishes (lap siding/stucco/T1-11) - Include any ADA/aging in place improvements as requested. - Discuss flooring: tile, LVT, engineered wood - Kitchen appliances, cabinets, and countertops - Types and quality of windows and doors - Lighting (recessed/flush mount) - Bathroom design - Entry porch or deck - Hardscaping (if desired) - Work with the Client on options to reduce costs such as placing the unit as close as possible to utility connections and selections of materials that fit the budget.

Once JML has a fully defined scope of work we will provide a fixed price cost to
the Client for them to decide if they want to proceed with us on the project before
money is invested in proceeding to obtain permits.

Going forward JML will provide one point of contact through these phases and
handle all aspects including handling all permitting, inspections, notifications,
and construction to completion and final sign off by the approving agencies.

Your Questions Answered






Are You Ready To Add An ADU To Your Property?

Our experienced team of professionals are ready to start designing your dream ADU


(925) 305 - 9333


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