ZIP 99361 falls in Walla Walla County, Washington, where we hold 6,181 parcels measured as septic county-wide and 13,089 on sewer. We do not have a per-ZIP parcel count for this county, so this is the county total, not a count specific to ZIP 99361.
ZCTA 99361 is not entirely inside one county. Land-area share is from the 2020 Census ZCTA-to-county relationship file.
| County | Land in this ZIP | Documents held | On septic (county) | On sewer (county) |
|---|---|---|---|---|
| Walla Walla County, Washington | 68% | — | 6,181 | 13,089 |
| Columbia County, Washington | 32% | 15 | 1,042 | 1,321 |
Land-area overlap is from the 2020 Census Bureau ZCTA5-to-county relationship file, not an estimate of ours. Parcel and document counts are rows we hold, not a survey of every property in the ZIP. Last verified 2026-09-01.
We hold 6,181 parcels measured as septic for Walla Walla County, Washington as a whole, not broken out by ZIP.
ZIP 99361 spans 2 counties: Walla Walla County, Washington, Columbia County, Washington.