Asotin County, WA zoning map, flood zone and property lines by address
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Towns in Asotin County: Clarkston Heights-Vineland, West Clarkston-Highland, Asotin.
Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA has 12 FIRM panels covering Asotin County, the newest effective October 2026; no coastal V zones are mapped in it.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for an Asotin house comes from a licensed surveyor and is often on file with the county or city building office.
Property lines
The parcel outline, parcel number and mapped size come from the Washington Technology Solutions (WaTech), statewide parcels from the counties, so an Asotin lot shows the same lines the county assessor draws. Asotin County covers about 407,088 acres of land and 2,790 acres of water.
Mapped lines are approximate. The Asotin County assessor keeps the parcel record (Asotin County website); a licensed surveyor sets the true corners.
Zoning
Asotin County zones its unincorporated land, and Asotin zones the land inside its limits. ParcelSheet shows the use the county assessor lists for the lot and links the county planning department for the district, the uses it allows and the lot size it needs.
ADU and guest houses
Under Washington's Planning Enabling Act and Growth Management Act (Revised Code of Washington Chapters 36.70 and 36.70A), local governments can allow an accessory dwelling unit on a lot with a house. Whether an Asotin lot can add one depends on its district; the county planning department has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. Asotin County is soil survey area WA603, Asotin County Area, Washington (Asotin and Garfield Counties), last updated September 2026, on Web Soil Survey.
A new or changed septic system in Asotin County needs a permit from the Asotin County health department (local health jurisdiction, under Washington State Department of Health on site sewage rules).
Setbacks
Setbacks in Asotin County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the county zoning office gives them for the lot's district, and Asotin for land inside its limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near an Asotin lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Asotin County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA has 12 flood map panels covering Asotin County, the newest effective October 2026. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Asotin County?
Open the Washington map, type the address, and the parcel outline from the Asotin County assessor shows on the map with its parcel number and mapped size. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in Asotin County?
Zoning in Asotin County is set by the county for unincorporated land and by each city (such as Asotin) inside its own limits. ParcelSheet shows the use code the county assessor lists and links the office that sets the zoning; the planning office has the final word.
Can I build an ADU in Asotin County?
Under Washington's Planning Enabling Act and Growth Management Act (Revised Code of Washington Chapters 36.70 and 36.70A), counties and cities can allow an accessory dwelling unit, and each sets its own rules. In Asotin County ask the zoning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in Asotin County?
Yes. A new or changed septic system in Asotin County needs a permit from the Asotin County health department (local health jurisdiction, under Washington State Department of Health on site sewage rules). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area WA603 (Asotin County Area, Washington (Asotin and Garfield Counties)).
What can I build on 5 acres in Asotin County?
Zoning in Asotin County is set by the county for unincorporated land and each city inside its own limits (such as Asotin). The zoning district decides the uses, how many homes and the smallest lot it allows on 5 acres. ParcelSheet shows the lot size as mapped and the use code on the parcel record; the planning office has the district and its rules. See the Asotin County website.
What are the residential setbacks in Asotin County (2026)?
Setbacks in Asotin County come from the zoning code of the county, or of the city when the lot is inside city limits: the front, side and rear distances depend on the lot's district. ParcelSheet does not draw setback lines or give a number it did not read; the zoning office gives them for the district. See the Asotin County website.
Next to Asotin County: Garfield County, Whitman County.
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