Installing, repairing or replacing your on-site sewage system (OSS)

Wastewater applications

• Instructions for Preparing an Appeal to the Health Officer via the King County Sewage Review Committee (SRC) Process
• Application for Final Subdivision
• Application for Health Department Approval of Building Permit
• Application for Health Department Review of Boundary Line Adjustment or Rezone
• Application for Winter Water Table Review (WWTR)
• Application to Change Designer of Record
• Pre-Application for Review of Subdivision
• Repair proposal form for on-site sewage system (OSS)|
  
  
• New application form! Site Design Application Form for Individual On-Site Sewage System (OSS)
  • See instructions on how to submit the On-Site Sewage System (OSS) Site Design application and required and optional checklist

Wastewater forms

Search and download an As-built Drawing for a property in King County

• Buyer's Declaration of Receipt of Copy of Notice of On-Site Sewage System Operation and Maintenance Requirements (example only)
• Drainfield Easement Form (example only)
• Declaration of Covenant: Detached Structure Restriction 
• Declaration of Covenant: Bedroom Restriction
• District Waiver Request
• Notice on Title Generic Form: Notice of On-site Sewage System Operation and Maintenance Requirements (OSSM)
• Non-conforming Notice on Title: Notice of On-Site Sewage System Operation and Maintenance Requirements
• Explanation of OSSM - Generic Form
• On-site Sewage System/Sewage Tank Service Report
• Report of Wastewater Tank Abandonment
• Waiver form for property transfer inspection

Miscellaneous forms

• Request form of public information needed by OSM to complete inspection report
• Approved Wastewater Tanks for OSS
• Property Owner Notification Letter

A site application design and installation permit are required when a new on-site sewage system is constructed. Construction must not begin until the installation permit is posted on the site/property.

• King County site development process flow chart
  Include qualified professional engineer to flow chart
  
  
• Winter Water Table Review
  If conditions on the property indicate a high seasonal water table, a winter water table review may be required. Consult with your septic system professional regarding this matter.
  • Download: Application for Winter Water Table Review (WWTR) (PDF)
    
    
• Questions to ask your OSS designer and master installer
  As with any person you may hire, you should interview at least 2-3 people. See lists of OSS professionals and key questions to ask when deciding who to hire.
  
  
• Appeal to the Health Officer via the King County Sewage Review Committee (SRC)
  An order or decision by the Health Inspector may be appealed through the Sewage Review Committee process. The committee may make recommendations to the program supervisor concerning the Health Inspector's decision or determination that is the subject of the appeal for reconsideration acting in an advisory capacity only. Appeals must be filed by 3:00 pm within sixty (60) calendar days from the date of the decision/order.
  • Download the Application form (PDF)
  
  Submit appeal package (form, proof of adjacent properties notification, exhibits, fee) to:
  
  Eastgate Environmental Health
  14350 SE Eastgate Way
  Bellevue, WA 98007
  Phone: 206-477-8050

• A public meeting is scheduled by the Sewage Review Committee to consider the appeal
• Meeting is typically  held at the subject property or at the Eastgate office.
• A written decision is mailed to the applicant and interested parties.

A repair proposal and permit is required when any change(s) or system replacements are made to your septic system. Below is a step-by-step guide for this process depending on what type of repair permit you need.

A building permit is required when you want to make significant changes by adding additional square footage (bedrooms, deck, recreation room, detached garage, etc.) to your property. Public Health - Seattle & King County is required to review remodel projects when the house is served by a septic system*. Construction should not begin until the local building department authorizes the project. Your septic system condition and capacity must be comparable to the changes made to the house after the remodel is complete.

1. You may apply for this review prior to or at the same time as the Building Department's review of your application.
   
   
2. While preparing your application, it is important to accurately describe the location of all septic system components on your site plan. Search and download a drawing of your septic system (As-Built drawing.)
   
   
3. The application must be filled out completely with 3 copies of everything.
   
   
4. Each application is reviewed by an inspector and receives a site visit. Examples the inspector are looking for includes:

• Age of septic system
• Condition of system
• Type of system
• Location of system as compared to area of remodel
• Presence of a reserve drainfield area
• Size of remodel
  • existing square footage vs. square footage being added
• Use of addition
  • are bedrooms being added?
  • number of bedrooms equals occupancy equals size of septic system
• Water source
  • a drinking water well requires certain setbacks to structures
  • structures must be served by an approved water source
• As-built and past permit history

5. Due to the scope of your remodel and condition, location and age of your septic system, you may be required to have the septic system evaluated by a licensed septic professional. The inspector will notify you in writing what this evaluation must include and what type of septic professional must be contacted.
   
   
6. You may also be required to upgrade or replace your septic system. For example, a house with an older septic system and a proposal to tear the house down to the foundation and rebuild it would require a new septic system.

Subdivisions

Public Health – Seattle & King County is required to review subdivision proposals when the properties are going to be served by septic systems*. The proposed drinking water source, minimum lot size evaluation and critical area review by the building official are part of the review process.
*A septic system is also referred to as an "on-site sewage system" in official documents, forms and applications.

There are two steps to acquire Public Health – Seattle & King County approval for subdivisions.

Step 1 - Subdivision Pre-application Report:

1. Property owner or agent contacts a licensed Designer or qualified Professional Engineer to evaluate the property and proposed subdivision.
2. Designer or qualified Professional Engineer submits a Subdivision Pre-application Report to Public Health.
3. If approved, the signed Subdivision Pre-application Report is sent to the designer and applicant by Public Health.

Step 2 - Application for Final Subdivision

1. After the local building department's requirements for compliance are fulfilled, the licensed Designer or qualified Professional Engineer submits an Application for Final Subdivision to Public Health.
2. If approved, the signed Application for Final Subdivision is sent to the designer and applicant by Public Health.

Boundary Line Adjustments (BLA) and Rezones

Public Health – Seattle & King County is required to review BLA and rezone proposals when the properties are served by septic systems*. In most cases, there will be a one-step review process. Availability of water supply is included in the review.

1. Property owner or agent contacts a licensed Designer or qualified Professional Engineer to evaluate the property and proposed BLA or rezone.
2. Agent or Designer or qualified Professional Engineer submits Application for Health Department Review of Boundary Line Adjustment or Rezone to Public Health.
3. If approved, the signed Application for Health Department Review of Boundary Line Adjustment or Rezone is sent to the designer and applicant by Public Health.

1. Licensed Designer or qualified Professional Engineer submits an Application for Health Department Review of Boundary Line Adjustment or Rezone for Public Health review of the BLA or rezone.
2. If approved, the signed Application for Health Department Review of Boundary Line Adjustment or Rezone is sent to designer and applicant by Public Health.

OSS repair and replacement (also, see section #3 above.)

A repair proposal and permit is required when any change(s) or system replacements are made to your septic system*. Below is a step-by-step guide for this process depending on what type of repair permit you need.

• Gravity System
• Mound System
• Pressure Distribution System
• Sand Filter System
• Sand Filter / Mound System