To find an approved septic as-built in King County, Washington, start with the county’s on-site sewage records map, search the address or parcel number, and open the drawing associated with that parcel. Use the county’s current building-project guide, Appendix A to check whether the PDF is an approved record drawing, not simply a plan filed under the property.
Find the parcel’s drawing, not just a map pin
The county’s septic-records page links the public map and describes its collection as designs, historical inspection reports, and as-built record drawings. In the map, use Find address or parcel number, then select the parcel and inspect its linked septic permitting PDFs. Turn on the King County Parcels layer to select a parcel. If the layer is gray, zoom in before trying again; a visible search match without a selected parcel is not yet the record list. The map’s Feature Info may also point to OnlineRME maintenance records, which answer a different question.
Copy the address and parcel number you searched and note any older address or replatting clue. Open the candidate PDFs rather than relying on a filename in the sidebar. Appendix A says most drawings appear under a dated “Asbuilt” label, while older material may appear as “(No Date) Unindexed.” That older label is a filing clue, not an approval stamp. A parcel can have an application design, a construction record, a maintenance sketch, or a later repair drawing; identify the system and work period shown on each document before treating two images as versions of the same plan.
Use this short document check on the PDF you intend to cite:
- Cover: Is there an “As-Built Sewage Disposal Plan” cover letter for the drawing?
- Professional: Is the drawing stamped or signed by a licensed on-site sewage designer or professional engineer?
- County: Does Public Health – Seattle & King County stamp or sign it with “As-Built”?
- Identity: Do the parcel, site, system layout, and drawing date fit the project you are researching?
The first three checks come from Appendix A. The identity check keeps a drawing from being assigned to the wrong parcel or a later system. An unindexed filename alone does not tell you whether the approval marks are inside the PDF.
Keep a dated drawing separate from later approvals
Hypothetical example: An older parcel has two map attachments: an undated unindexed sketch and a later dated as-built. The sketch may help locate a tank, while the later file may document the built system. If approval or system identity is missing or illegible, ask Public Health which file it recognizes rather than choosing the newest-looking image. A dated record drawing does not report today’s performance.
The building-project guide says an applicant can save the approved drawing and upload it with the Public Health Building Project Review. That review concerns a proposed building project’s effect on the septic system. It is not the same document as the as-built, a maintenance inspection, the building permit, or the building permit’s final inspection. Ask for each separately if the question spans construction and later use. OnlineRME may show maintenance reports or sketches, but finding a maintenance record does not by itself authenticate an approved as-built.
When the map has no usable as-built
The county’s record-help instructions identify several reasons a PDF may be absent: an older house, an unpermitted installation, final construction papers never submitted, an address or parcel change, or microfiche not yet scanned. The map’s description of digitized material extending back toward the early 1960s does not promise an online drawing for every property in that era; the county separately warns that houses built before the early 1970s may lack online records. Many pre-1998 records exist but can be less detailed or legible. No map result does not prove there was no septic permit or approved drawing.
Email as-built.help@kingcounty.gov with the parcel number and street address, as the county instructs. Add the former address, approximate installation or repair period, and the label or PDF you checked if known. Ask specifically for the approved record drawing, whether an older microfiche or differently indexed file exists, and which identifier staff needs to distinguish a repair from the original installation. If the county has no copy, its page suggests asking the system designer or engineer. Our no-result lookup guide explains how to keep the failed search terms and staff response together. Keep the county’s response with the drawing you ultimately use, especially when its approval marks or system identity remain uncertain.
Waterfront parcels can also carry a shoreline decision; see how a King County shoreline variance moves from county decision to Ecology review.
Official King County records guidance, map help, and the current building-project guide were checked September 30, 2026.