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

Many homeowners ask if they need to get a survey or grading plan before proceeding with the planning & permitting process for their ADU. While you will need a site plan to submit for permits, a survey is typically not required for ADUs in North County San Diego, including Oceanside, Carlsbad, Encinitas, San Marcos, Vista and other nearby municipalities. Read on for considerations when you are thinking about if you need a survey for your ADU project.

Do I need a survey for my ADU?

Whether you need a survey for your ADU will depend on your jurisdiction, site conditions and even the building inspector you happen to get for your project. Most jurisdictions state they will not require a survey for an ADU. You likely can even get through plan check, all the way to permit-ready status without the need for a survey being raised by the city. However, each jurisdiction will leave the final decision up to the inspector who, upon visiting the site, may decide a survey is necessary.

If possible, we attempt to flush this out during plan check or by having a “pre-construction” meeting on-site with the inspector prior to starting work. However, not all inspectors will extend the courtesy of a pre-constructing meeting. The first on-site inspection takes place when the foundation is ready to pour, meaning the inspector could stop the project and require a survey before any work can continue, resulting in delays.

How much does a survey cost?

Depending on what kind of detail you need, the price of a survey can vary quite a bit. If doing a boundary survey and limited topography lines for basic site engineering, it may cost around $3,000. A building location survey typically starts at $5,000. Full grading plans for civil engineering can add thousands more, as can revisions and processing for plans. We work to determine the most cost-effective placement of the ADU to minimize need for these surveys whenever feasible.

How do I avoid the need for a survey?

SnapADU handles the design process – as well as construction – in order to help anticipate and avoid additional requirements and fees. During our initially feasibility study, we analyze the site and determine the best layout for the ADU. While ADU regulations allow for reduced setbacks, it is not always advisable to push up against them.

We are in regular contact with all sorts of folks in the ADU space, from inspectors to surveyors to the heads of building departments. The common sense approach they often advise is to place the ADU far enough from a setback whereby the issue of encroachment is less likely to be considered, since there is clearly sufficient setback (even if the property line were found to be a few inches “off” from where it is claimed to be). We typically allow a minimum of 1’ of additional buffer space between the setback and the edge of the ADU.

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

In some cases, it may be prudent to go ahead with a survey even though it is not required. 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.

If an inspector requires a 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.

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.

We try to mitigate potential setback and grading issues by considering the overall costs when placing your ADU on the site plan. But if you have a challenging lot, getting a survey is a bit like an insurance policy.