When do you need a survey for an ADU in San Diego?

Many homeowners ask if they need a survey before proceeding with the planning & permitting process for their accessory dwelling unit (ADU). While you will need a site plan to submit for permits, a boundary survey may or may not be required for ADUs in the County of San Diego. Read on for considerations when you are considering whether you need a survey for your ADU project.

Do I need a survey for my ADU?

Whether you need a survey for your ADU, and what type of survey, depends on several factors. This includes your jurisdiction requirements, site conditions, ADU location, and even the building inspector.

Over the past few years, you may have been able to get through plan check without a survey. However, many cities are now requiring boundary surveys for all ADU projects. Also, some jurisdictions leave the final decision up to the inspector who may decide a building verification survey is necessary. They may do this even if it wasn’t required for an initial building permit. The inspector could then stop the project and require a survey before any work can continue. This can result in delays and unforeseen costs.

At SnapADU, we prioritize thorough planning and budgeting from the outset. To facilitate this, we include a basic planimetric/topographic survey for all our ADU projects. This survey is crucial for accurate planning and budgeting. It helps to establish a buildable pad for the ADU by assessing the site’s existing conditions and features.

For ADUs positioned close to property boundaries, within 2 feet of a setback, a more detailed boundary survey is typically mandated by the city. This survey is essential to ensure that the ADU is placed adhering to local zoning and setback requirements. We aim to provide homeowners with a clear and predictable path by incorporating these surveys early into our process

What are the different types of surveys related to planning for an ADU?

Planimetric & Limited Topographic Survey

A planimetric survey maps your property’s layout, including buildings, trees, driveways, and other features. This “bird’s-eye view” helps to understand how the land interacts with your proposed ADU. A limited topographic survey adds elevation data, crucial for foundation design and drainage.

Including a planimetric & limited topographic survey in the feasibility study allows for a more accurate assessment of construction costs and potential site-related challenges. It’s a proactive step that helps avoid costly surprises during construction and ensures that the ADU is designed with a full understanding of the site’s topographical nuances.

Boundary Survey

A Boundary Survey formally locates the property lines of the parcel in question. It’s essential to ensure that the ADU is placed accurately and in compliance with the setbacks.

By completing a Boundary Survey, you’ll have a clear understanding of the property lines, which is critical to ensuring that the ADU is constructed in the correct location and meets all zoning and building code requirements.

Building Verification Survey

A building verification survey (BVS) verifies that your ADU is placed correctly on your property. It’s a follow-up survey required by some cities, like San Marcos and Carlsbad. Note that a boundary survey must be done first.

TABLE: Survey Scope and Cost Overview for Snap ADU Projects

*Boundary Survey pricing may vary depending on the complexity of the property and the existence of recorded survey monuments in close proximity.

How much does a survey cost?

The cost of a survey is largely based on the existing surveys and information that are recorded with the county surveyor’s office. In most cases, a boundary & building verification survey would cost between $4-10K.

Many other factors can influence cost. For example, if the last survey on record was from 1930 on a parcel 2 blocks away, this would be an expensive survey because the surveyor is effectively starting from scratch and has to map the entire area surrounding the parcel as well, which of course takes significant time. It’s important to get a quote on a survey for your specific property to ensure you know how much it will cost upfront. Your contractor will be able to solicit this quote for you and include in the overall scope of work.

Full grading plans for civil engineering can add thousands more. These plans are required when your site involves a steep slope.

When in the ADU project should a survey be conducted? How long does it take to get a survey?

A survey typically takes 1-2 days to conduct the field observations, and 1-2 weeks to compile and record the findings with the County surveyor’s office. However, surveyors are in high demand and often have a lead time upfront of 2-3 weeks to schedule a survey.

To ensure seamless integration into your project timeline, it is advisable to undertake this survey during the Feasibility & Design phase. This allows the findings to be incorporated into the construction documents. Our established relationships with a network of trusted surveyors enable us to schedule these services with predictability. Therefore, we are able to avoid unnecessary delays in your project’s progression.

When should I go ahead and get a survey for my ADU?

At SnapADU, we understand the importance of starting your ADU project on solid ground. That’s why we perform a planimetric/topographic survey in all of our ADU feasibility studies.

In some cases, it may be prudent to go ahead with an additional type of survey even though it is not required by the jurisdiction. If you have a challenging lot with a hillside, easements, or other constraints that make design & planning less straightforward, it may be necessary to proceed with a survey. This serves to, again, eliminate the number of surprises you encounter during your ADU build.

If an inspector requires a building verification or boundary survey and you don’t have one, it can stop construction progress and delay the project weeks or even months, and potentially cause a redesign if we have to move the building to account for new setbacks. During this time, you will likely accumulate additional costs as you stop and restart the build process. Overall, putting off a survey usually ends up hurting your build in the long run. Thus, it is well worth your time and money to have your property surveyed early on.

Even if the city never requires a survey, there could be downstream consequences after the ADU is built. A neighbor could bring up a property line issue, force a survey, and potentially find an encroachment. This means you could in theory have to move the building after it has been constructed – not something any homeowner wants to be faced with.

In essence, a survey acts as an insurance policy for your build, providing detailed information about your property and ensuring the ADU is constructed within the proper boundaries. By investing in a survey with SnapADU, you’re not only facilitating a smoother build process but also safeguarding against future disputes, securing peace of mind for the years to come.

I already have a survey… what elements would it need so that SnapADU could use it?

1. The survey shows the most current state of the property. This should include any additions or other work that has impacted the site.
2. CAD format (.dwg) and PDF format files are both required.
3. Boundary survey accurately plots all property corners and lines that comprise the parcel boundaries.
4. Planimetric survey elements accurately plot all current existing site improvements and natural features including but not limited to structures, fences, landscaping, hardscapes, paths, walls etc.
5. Topographic survey elements accurately plot all contour lines in 1′ increments showing the current grade elevations across the property in relation to sea level.
6. Survey document clearly plots all easements with dimensions in relation to the property lines.
7. If for some reason we have to prove out grading quantities or confirm the building pad elevation, the survey should include the elevation data source used (NGVD 29 or NAVD 88) on the plan. Example below.

How to use expertise to avoid surprises

The information provided in this blog is based on our extensive experience in design, permitting, and building ADUs. It’s important to note that regulations may vary in different areas, and local interpretations can differ. We strive to anticipate the most common scenarios and interpretations to provide accurate advice on budget and scope to our clients. Our goal is to ensure that there are no surprises, particularly when it comes to costs and the overall process. However, we do hope that you’ll be pleasantly surprised by how smoothly things go and how amazing your ADU looks upon completion!