Plot Plans for Well & Sewage Systems

What is a plot plan?

A "plot plan" is a drawing viewed from above that shows the locations of important features of your property. (Think of looking down at your property from an airplane.) The plot plan is best prepared by a qualified engineer or architect, but many homeowners choose to draw the plot plan.


Why do I need a plot plan?

A plot plan is required in order to obtain a well or sewage permit because:

  • It makes sure the sewage system is located in the area that was approved during the soil evaluation.
  • It makes sure that required isolation distances are met for well and sewage systems.
  • It provides a record for future maintenance and construction.


What should be considered when creating a plot plan?

Thought should be put into the site layout, so go to the property and think about where things should be located. Consider plumbing and drainage, and make sure septic tanks are located in a place that is easily accessible for pumping. Also, the only covering that should be over the drainfield is grass, so it should be in a location where other landscaping will not take place, and where other buildings such as sheds or garages will not be built.


What are the requirements for a plot plan?

If your plot plan does not include all these items or is inaccurate, it may result in delays obtaining your permit. Contact Environmental Health at (734) 222-3800 for more detailed instructions on drawing a plot plan if you need help.

Plot Plans Must:

  • Show property lines.
  • Show locations of all existing construction on your property, and any construction that is on adjoining property within 150 feet of your proposed well or sewage system.
  • Include buildings, driveways, wells, septic tanks, drainfields, swimming pools, decks, buried fuel tanks, etc.
  • Show locations of all proposed construction on your property.
  • Include buildings, driveways, wells, septic tanks, drainfields, swimming pools, decks, buried fuel tanks, etc.
  • Include information regarding the size and location of your proposed septic tanks and drainfield. Remember to include where the sewer pipe will exit the house, and the location of the soil test pits.
  • Include surface water features of your property, such as streams, wetlands, lakes, flood plains, etc.
  • Include slopes or hills. These may warrant additional information or drawings, if the Sanitarian deems it necessary.
  • Include your name, the address of the property, a NORTH arrow, and the scale used to draw the plot plan. Example: (SCALE: 1"= 40').
  • Be drawn to "scale". This means that a given length on a ruler is equal to a given distance on your land. A typical scale is 1 inch to 40 feet. A plot plan drawn to a scale of 1"=40' means that one inch on your plot plan represents 40 feet on your land. At this same scale, an inch would represent 20 feet on your property. Everything that is shown on your plot plan must be located and drawn to scale.
    • Example: You want to draw your house to a scale of 1 inch to 40 feet, and your house is 30 feet wide by 60 feet long. Since 30 (house width), divided by 40 (scale) = 3/4, and 60 (house length) divided by 40 (scale) = 1 , you can draw a box measuring " x 1 " to represent your house "drawn to scale". We also need to be sure that your house is drawn on your plot plan in the right location. If you want your house 200 feet south of the north property line and 125 west of the east property line, locate your house on your plot plan as follows: Measure south 5 inches (200/40=5) from your north property line and measure west 3 1/8 inches (125/40=3 1/8) from your west property line. If the entire parcel will not fit on an 8 " x 11" sheet of paper at the desired scale, simply show "broken lines" with the property line distance indicated. An engineer's scale is available from art/office supply stores that will have a "40 scale" on it. Using this, a 40 scale means one inch is equally divided into 40 segments, each of which would represent one foot on your plot plan.


Sample Plot Plan


For more information, please contact:

  • Your Area Sanitarian (based on your Township)
  • Washtenaw County Environmental Health Division - (734) 222-3800
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