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Programs - Onsite Sewage (Septic) Systems - Permitting

Permitting

Island County Public Health issues permits for new and repair construction of onsite sewage (septic) systems.  The process can be very challenging as a homeowner.  However, our staff is here to be a resource to you and your designer.

Our Sanitarians work with hundreds of designs a year.   This, along with official certification and licenses, provides you with a public health staff that will bring creative and efficient solutions to your onsite sewage treatment needs.

Below is information on the permiting process.

 

The Permitting Process & General Information

  

The Site Registration:
 
The Site Registration (SR, Perc, etc.) is typically the first step in the process of obtaining permit(s). A Site Registration is a recorded document filed with Island County describing various conditions found on a site. A licensed designer is responsible for submitting the Site Registration.   Based on the site characteristics the site may or may not be capable of supporting an on-site sewage disposal system. A typical Site Registration will provide a description of soil texture, soil depths, slopes, and water tables. Other features such as wells, bluffs, critical areas, property dimensions, and easements are also recorded on the Site Registration. The Site Evaluation does not expire and is acceptable so long as the findings remain valid. Certain activities such as grading, filling or logging of the property can alter the original findings and render the Site Registration invalid.  
 
 
The Permit:
 
Typically, the next step in the process is to apply for a permit to construct a sewage disposal system. A licensed designer will draw up a plan based on the site registration and your use of the property. The type of septic system will be either conventional or alternative depending on site conditions and use. Based on the number of bedrooms and/or water use the designer will draw a plan with septic tanks, pump tanks and drainfield lines that are sufficient in size to support the use. The plan should include information such as well location, easements, utilities, dwelling size, dwelling dimensions, driveways, surface water, critical areas, and bluffs.   The designer will submit a copy of the application to the Health Department for review. If the plan meets all requirements and a valid water share has been identified, a permit will be issued. The permit is valid for three years. If the permit expires before the system is installed, a new design meeting all codes must be resubmitted. At the time the permit is issued, the septic permit can be used to apply for a building permit(s).
 
The As-Built:
 
After the sewage disposal system has been installed, the installer will draw up an as-built. The as-built will detail any deviations between the permit and what was installed. The as-built is a scaled drawing showing where dwellings, tanks, utilities, property lines, wells, drainfield(s) and other important features are located. The as-built will have technical information on it as well. Items such as pump models, timer settings, dosing regimes, orifice size, residual pressures, and proprietary devices will be listed. This drawing can be used by the system owner to locate components, making system maintenance convenient.
 
  
 
Table IV
                                      Minimum Horizontal Separations
 
 

 

Items Requiring Setback
From edge of soil dispersal component and reserve area
From sewage tank and distribution box
From building sewer, and nonperforated distribution pipe
Well or suction line
100 ft.
50 ft.
50 ft.
Public drinking water well
100 ft.
100 ft.
100 ft.
Public drinking water spring measured from the ordinary high-water mark
200 ft.
200 ft.
100 ft.
Spring or surface water used as drinking water source measured from the ordinary high-water mark1
100 ft.
50 ft.
50 ft.
Pressurized water supply line
10 ft.
10 ft.
10 ft.
Decommissioned well (decommissioned in accordance with chapter 173-160 WAC)
10 ft.
N/A
N/A
Surface water measured from the ordinary high-water mark
100 ft.
50 ft.
10 ft.
Building foundation/in-ground swimming pool
10 ft.
5 ft.
2 ft.
Property or easement line
5 ft.
5 ft.
N/A
Interceptor/curtain drains/foundation drains/drainage ditches
 
 
 
 
Down-gradient2:
30 ft.
5 ft.
N/A
 
Up-gradient2:
10 ft.
N/A
N/A
Other site features that may allow effluent to surface
 
 
 
 
Down-gradient2:
30 ft.
5 ft.
N/A
 
Up-gradient2:
10 ft.
N/A
N/A
Down-gradient cuts or banks with at least 5 ft. of original, undisturbed soil above a restrictive layer due to a structural or textural change
25 ft.
N/A
N/A
Down-gradient cuts or banks with less than 5 ft. of original, undisturbed soil above a restrictive layer due to a structural or textural change
50 ft.
N/A
N/A
Other adjacent soil dispersal components/ subsurface storm water infiltration systems
10 ft.
N/A
N/A
 
 

                                                                    TABLE VIII

 

Maximum Hydraulic Loading Rate Soil Type
Soil Textural Classification Description
Loading Rate for Residential Effluent Using Gravity or Pressure Distribution
(gal./sq. ft./day)
1
Gravelly and very gravelly coarse sands, all extremely gravelly soils excluding Soil types 5 & 6, all soil types with greater than or equal to 90% rock fragments.
1.0
2
Coarse sands.
1.0
3
Medium sands
0.8
Loamy coarse sands, loamy medium sands.
0.64
4
Fine sands
0.6
Loamy fine sands, sandy loams, loams.
0.48
5
Very fine sands, loamy very fine sands; or silt loams, sandy clay loams, clay loams and silty clay loams with a moderate structure or strong structure (excluding a platy structure).
0.4
6
Other silt loams, sandy clay loams, clay loams, silty clay loams.
0.2
7
Sandy clay, clay, silty clay and strongly cemented firm soils, soil with a moderate or strong platy structure, any soil with a massive structure, any soil with appreciable amounts of expanding clays.
Not suitable

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