Elmore County, ID zoning map, flood zone and property lines by address
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Towns in Elmore County: Mountain Home, Glenns Ferry, Mountain Home Air Force Base.
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 10 FIRM panels covering Elmore County, the newest effective November 2010; 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 Elmore 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 State of Idaho public parcels, from counties that share them, so an Elmore lot shows the same lines the county assessor draws. Elmore County covers about 1,968,050 acres of land and 16,885 acres of water.
Mapped lines are approximate. The Elmore County assessor keeps the parcel record (Elmore County website); a licensed surveyor sets the true corners.
Zoning
Elmore County zones its unincorporated land, and Mountain Home, Glenns Ferry each zone the land inside their limits. ParcelSheet shows the use the county assessor lists for the lot and links the county planning and zoning office for the district, the uses it allows and the lot size it needs.
ADU and guest houses
Under Idaho's Local Land Use Planning Act (Idaho Code Title 67, Chapter 65), local governments can allow an accessory dwelling unit on a lot with a house. Whether an Elmore lot can add one depends on its district; the county planning and zoning office 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. Elmore County is soil survey area ID685, Elmore County Area, Idaho, Parts of Elmore and Owyhee Counties, last updated August 2026, on Web Soil Survey.
A new or changed septic system in Elmore County needs a permit from the public health district that serves Elmore County (under Idaho Department of Environmental Quality rules).
Setbacks
Setbacks in Elmore 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 Mountain Home and Glenns Ferry for land inside their limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near an Elmore lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Elmore County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA has 10 flood map panels covering Elmore County, the newest effective November 2010. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Elmore County?
Open the Idaho map, type the address, and the parcel outline from the Elmore 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 Elmore County?
Zoning in Elmore County is set by the county for unincorporated land and by each city (such as Mountain Home, Glenns Ferry) 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 Elmore County?
Under Idaho's Local Land Use Planning Act (Idaho Code Title 67, Chapter 65), counties and cities can allow an accessory dwelling unit, and each sets its own rules. In Elmore 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 Elmore County?
Yes. A new or changed septic system in Elmore County needs a permit from the public health district that serves Elmore County (under Idaho Department of Environmental Quality rules). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area ID685 (Elmore County Area, Idaho, Parts of Elmore and Owyhee Counties).
What can I build on 5 acres in Elmore County?
Zoning in Elmore County is set by the county for unincorporated land and each city inside its own limits (such as Mountain Home, Glenns Ferry). 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 Elmore County website.
What are the residential setbacks in Elmore County (2026)?
Setbacks in Elmore 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 Elmore County website.
Next to Elmore County: Ada County, Blaine County, Boise County, Camas County, Custer County, Gooding County, Owyhee County, Twin Falls County.
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