ZIP 99350 falls in Benton County, Washington, where we hold 12,111 parcels measured as septic county-wide and 47,868 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 99350.
ZCTA 99350 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) |
|---|---|---|---|---|
| Benton County, Washington | 87% | — | 12,111 | 47,868 |
| Klickitat County, Washington | 13% | 10 | 6,529 | 3,763 |
| Yakima County, Washington | 1% | 1 | 28,790 | 42,671 |
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 12,111 parcels measured as septic for Benton County, Washington as a whole, not broken out by ZIP.
ZIP 99350 spans 3 counties: Benton County, Washington, Klickitat County, Washington, Yakima County, Washington.