In Clackamas County, Oregon, which covers part of Lake Oswego, we have measured 19,805 parcels on septic and 101,964 on sewer. That is a county measurement. We do not hold a septic count for Lake Oswego on its own and this page does not estimate one. Lake Oswego also extends into Multnomah County and Washington County, which are reported separately below and are not included in that figure.
Lake Oswego is a city in Clackamas, Multnomah and Washington Counties, Oregon. The Census Bureau puts its internal point at 45.413551, -122.700007 and its land area at 10.87 square miles. Septic permitting and record keeping happen at the county level, not the city level, which is why every figure below is attributed to the county and linked back to the county page it came from.
| County | Records we hold | Parcels on septic | Parcels on sewer | County records portal | Searchable without an account |
|---|---|---|---|---|---|
| Clackamas County | 10,784 | 19,805 | 101,964 | county portal | no account needed |
| Multnomah County | 5,457 | 2,955 | 207,636 | county portal | account or login required |
| Washington County | 0 | 10,442 | 134,730 | county portal | account or login required |
We hold 10,784 septic records for Clackamas County, Oregon. That is a substantial partial collection rather than a complete one, so a Lake Oswego property may or may not appear in it, and the county archive remains the authority. The county is predominantly sewered: only 19,805 of 121,769 classified parcels are on septic. Septic properties near Lake Oswego are the exception, which is exactly why owners often do not know they have one. The county publishes a records portal that we were able to search without creating an account, which makes checking a specific parcel something you can do yourself in a few minutes.
Septic is one subject with very different jobs inside it. These go straight to the page that does yours.
| If you are a | Go to | Because it covers |
|---|---|---|
| Homeowner | Septic pumping in Lake Oswego | keeping the system you have working |
| Buyer or seller | Buying or selling in Lake Oswego | what to pull and check before closing |
| Realtor | Buying or selling in Lake Oswego | the same records a seller needs on file |
| Designer or engineer | Septic design in Lake Oswego | design flow, tank capacity, dispersal sizing |
| Installer or contractor | Septic installation in Lake Oswego | site evaluation, permit sequence, inspection |
| Septic pumper | Septic pumping in Lake Oswego | tank access, lids and service interval |
| Inspector | Septic inspection in Lake Oswego | what gets checked and what a failure means |
| Land investor | Septic installation in Lake Oswego | whether raw land can take a system at all |
No. We measure septic and sewer at parcel level and roll it up by county. In Clackamas County, Oregon, which covers part of Lake Oswego, we have measured 19,805 parcels on septic and 101,964 on sewer. That is a county measurement. We do not hold a septic count for Lake Oswego on its own and this page does not estimate one. Lake Oswego also extends into Multnomah County and Washington County, which are reported separately below and are not included in that figure.
Lake Oswego is in Clackamas, Multnomah and Washington Counties, Oregon.
From the Census ZCTA-to-place relationship file, with the share of Lake Oswego’s land area that falls in each. A ZIP is not a place boundary and the two only ever partly agree, which is exactly why both pages exist.
Straight-line distance from the Census internal point of Lake Oswego.
Parcel Perfect generates a code-shaped septic design and as-built style drawing for a parcel from the records and site data we hold, and shows every parcel we have classified as septic or sewer on one map. Both are open to use for any parcel in Clackamas, Multnomah and Washington Counties, Oregon.