Onsite design application
Instructions on how to submit online
- Go to Environmental Health's online services portal.
- If you are a new user, click on "First-time users register here."
- If you previously created an account, click on "Registered users log in here."
- Once you are logged in, from the left side menu, click on "OSS plan review."
- Click on "Add OSS Plan Review" and complete the application process and attach your application document.
- After you have completed the application and paid your fee, you will be able to print the application for your records, you will receive a confirmation email, and you can check the status of your application at www.kingcounty.gov/oss/status.
Application document checklist
|No.||Type of document||Additional instructions||Conditions that initiate requirement|
|1||Vicinity Map||Must include gate code, presence of dogs, and details needed for the inspector to locate the proposed/existing well & OSS site||Required for all applications|
|2||Detailed Site Plans and specifications||Maximum paper size is 11” x 17” (Detailed site plan: 1” to 20’ or the largest scale that will allow; Overall site plan may be scaled as needed for example, 1” to 50’ or 100’; Sewage Tank Invert & Plumbing Stub Elevations; and Details of proposal per Title 13 Code requirements – remember to check neighboring properties for wells, OSS, and storm water systems||Required for all applications|
|3||Hydraulic Calculations||Should include clear calculations, preferably on a single page||Required for all applications|
|4||Soil Log Data||
Minimum of 5 soil logs - 2 each drain field & reserve area + 1 for tank(s) (Remember to document the soil log for the septic tank).
If a treatment device, such as a sand filter or ATU unit, is greater than thirty feet from the wastewater tanks, then one soil log shall be located in the area of the treatment device.
|Required for all applications|
|5||Treatment Product Specifications||Document ONLY what is needed for design and installation – documentation that is available in the design manual does not need to be included||Required for all applications|
|6||Critical Area Designation||Required for new On-site sewage design|
|7||Sewer Letter||Sewer letter should state what the distance from property line to nearest sewer is greater or less than 200 feet||Required for On-site sewage system in urban area|
|8||Valid (one year) water Availability Letter||Required if property is in public water system area|
|9||Current Bacteria test||If Applicable|
|10||Nitrate test and Arsenic Result||If Applicable|
|11||DRAFT well covenant(s)||Required if water source is “Proposed Private Individual Well”|
|12||Copies of covenants||Required if water source is “Existing Private Individual Well”|
|13||Proof of lot segregation date||
Required if water source is “Proposed Private Individual Well” and property is less than 5 acres.
If Drainfield EasementOr if applicable
|14||Well construction log||Required if water source is “Existing Private Individual Well”|
|15||Easement survey||If Applicable|
|16||Draft Drainfield easement language||
Required If Drainfield Easement
|17||Draft easement language||If Applicable|
|18||Other_1||Optional for any type of applications|
|19||Other_2||Optional for any type of applications|