How to get a site plan for your building permit

Are you embarking on a residential building or remodeling project with excitement, anticipation, and a little trepidation? If you aren’t working closely with a knowledgeable engineering consultant from the start, the process of obtaining a building permit may hold a few surprises that can bog down your project and cause confusion. One commonly misunderstood aspect of residential permitting is the site plan requirement. Most jurisdictions require a site plan to be submitted with any new building permit application regardless of whether or not the project is land-disturbing. Many homeowners don’t anticipate this requirement and have questions about why they need a site plan and how to obtain one. We’re here to answer those questions and provide resources to help you get through the permitting process and on to the more exciting phases of your residential building project.


What is a site plan? 

A site plan is a document that is drawn to a standard engineering scale to illustrate and specify important details about a piece of property and its existing and proposed structures. A site plan illustrates not only lot lines, boundaries, and structures, but also septic tanks, wells, drain fields, adjacent right-of-ways, private roads and easements, and their setbacks, among other things. It also maps any Native Growth Protection Areas, water bodies, or steep slopes on the property. Most jurisdictions require a detailed site plan to be presented with a building permit application. Exceptions are sometimes made for reroofing and siding permits, mechanical or plumbing only permits, and demo permits. 

Each jurisdiction has its own requirements for exactly what must be shown on a site plan. In addition to a plan for building, drainage, and critical areas, some jurisdictions require a second site plan that details temporary erosion and sedimentation control for certain projects. It is important to obtain information about requirements directly from your jurisdiction, or from a consultant with knowledge of the requirements, prior to attempting to permit a project to avoid rework and delays. 

Site plan requirements can usually be found on the jurisdiction’s website. Some break down the requirements by project size or scope, requiring less detail for simple residential projects and more detail for complex ones. Smaller jurisdictions may not publish this information online and you may need to visit the local planning office to obtain the proper checklists for your site plan. 

Here are a few links to site plan requirements for local jurisdictions in Western Washington: 

Snohomish County
King County
City of Seattle
City of Everett 


Why do I need a site plan if I am not adding any new structures to my property? 

A site plan is an important tool to let your jurisdiction know that you are following the building codes and zoning regulations for your project. It also helps you identify any problems with your development plans that could impact insurability, compliance with future laws, and adequate infrastructure. Site plans are recorded with the jurisdiction and serve as a historical record of development that has taken place on your property over many years, making them a very important and interesting way to see how development has impacted your property and community over time. Even if you are not adding new structures, your jurisdiction wants to keep a detailed record of your property for future and historical reference, and for infrastructure planning. 


Where can I get a site plan? Can I create my own?  

Before you start creating a site plan, make sure you don’t already have one to start from. County or city records are a great place to find previous site plans for anything that has been built in the past fifty years or so. Many larger jurisdictions make property records available in an online searchable database. For instance, Snohomish County offers a wealth of information on its PDS website. You can also submit an online information request for records that are too old to be found online. Note:  If you are working with a consultant, they will usually complete this information-finding step for you as part of their site planning process. 

Whether you have a starting point or you are starting from scratch, it is a good idea to consult with a professional about creating a site plan. If you want to, and feel confident in your ability to meet all requirements, you may be able to draw a site plan yourself for a simple project. For many types of projects, a topographic survey will be needed to submit to the jurisdiction for a permit.  Your engineering consultant can help to determine if a survey is needed. If you don’t want to tackle this job, or if you want to ensure the site plan is done professionally and permitting is not held up by reworks, it is wise to engage with a consultant that specializes in engineering, permitting and site plans. If you are working with an engineer or survey firm on your project, they are the best place to go for a site plan because they are already familiar with your project, the jurisdiction, and your wants and needs. 


CG can help with site plans and other permitting questions

Making a site plan is not usually a complex or costly process, but there is a chance it will reveal the need for additional consultants to prepare reports for permitting, particularly if your property has wetlands, steep slopes, or other sensitive areas. We can work with you to determine if you actually need additional consultants to review these areas or if they can be simply indicated on the site plan as existing. Then, we can handle all of the steps to get your permit approved. 

Are you excited about your project again? We hope so. If you are interested in engaging with CG Engineering for your project, contact us here

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