Site Plans for Well & Sewage Systems
A site plan (also called a plot plan) is required to obtain a sewage permit, septic tank only permit, or well permit. A site plan is also required for an addition/change of use review.
A site plan is a drawing viewed from above that shows the locations of important features of your property. Think of yourself in an airplane looking down at your property. Having an accurate site plan helps ensure that the sewage system is located in the area that was approved during the soil evaluation, and that the well is isolated from possible sources of contamination. The site plan also provides a record for future maintenance and construction. Although the site plan is best prepared by an engineer or architect, many homeowners choose to draw or create one.
Careful thought should be put into the site layout of your property. Go to the property and think about where you would like the house to be located. Keep in mind the house location may need to change based on site conditions. Consider plumbing and drainage, and make sure septic tanks are located in a place easily accessible for pumping. Since the drainfield area should only be covered with grass, make sure it is in a location where no other landscaping will take place, and where no swimming pools, sheds, barns, garages, or livestock yards will be built.
Find Existing Site Plans and Property Information
Check prior records and maps for helpful information about the property, and for assistance in creating a site plan.
OnBase - Previous site plans; well, septic, building inspection, and soil erosion permits. For best results, only enter the street number of the address and search: www.washtenaw.org/permitrecords
MapWashtenaw - Parcel maps and property data: www.washtenaw.org/mapwashtenaw
Site Plan Tutorial - Video showing how to use MapWashtenaw to create a site plan: http://bit.ly/siteplanmap
If you find an existing site plan in the online records, you can usually just update that plan and submit it with your application. Indicate on the plan the new features and any changes since the plan was initially approved. Be sure to mark items in the correct location, and of the correct size.
Site Plan Requirements
Site plans must be accurate, must be drawn to scale, and must include the following details:
Existing and proposed property lines.
Existing and proposed construction on the property, including the house, driveways, sidewalks, decks, garages, sheds, swimming pools, fuel tanks, geothermal wells/loops, etc.
Existing and proposed well location(s).
Existing and proposed septic tank(s) and drainfield(s).
Approved soil test pit locations.
Where the sewer pipe will exit the house.
Locations of any well or sewage system on adjoining property within 150’ of the subject property.
Surface water features on the property, such as streams, wetlands, lakes, flood plains, etc.
Slopes or hills. These may warrant additional information or drawings if the sanitarian deems it necessary.
Your name, the address of the property, an arrow indicating the direction of NORTH, and the scale used to draw the site plan. (Example: SCALE: 1”= 40’)
Site Plan Drawn to Scale
A site plan drawn to scale means that a given length on a ruler is equal to a given distance on your land. A typical scale used for site plans is 1 inch to 40 feet (1”=40’), meaning that one inch on paper represents 40 feet on your property.
An engineer’s scale (similar to a ruler) is available from art/office supply stores that will have a “40 scale” on it. A 40 scale means one inch is equally divided into 40 segments, each of which would represent one foot on your site plan.
You could also use graph paper to draw your site plan. Just be sure to include the scale you are using (for example, one square = 10 feet).
If the entire parcel will not fit on an 8.5” x 11” sheet of paper at the desired scale, show "broken lines" with the property line distance indicated.
Examples using a scale of 1”=40’:
Making your house the right size. Your house is 30’ wide by 60’ long. Since 30 (house width), divided by 40 (scale) = 3/4, and 60 (house length) divided by 40 (scale) = 1.5, draw a box 3/4-inch x 1.5-inch to represent your house drawn to scale.
Drawing your house in the right location. You want your house 180’ south of the north property line, and 35’ east of the west property line. Measure south 4.5 inches (180/40 = 4.5) from your north property line, and measure east 7/8 inches (35/40 = .875) from your west property line.