Cass County, NE zoning map, flood zone and property lines by address
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Towns in Cass County: Plattsmouth, Louisville, Weeping Water.
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's countywide study for Cass County has 39 FIRM panels, the newest effective August 2024; 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 a Cass 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 NebraskaMAP statewide parcel layer (from each county assessor), so a Cass lot shows the same lines the county assessor draws. Cass County covers about 356,423 acres of land and 5,747 acres of water.
Mapped lines are approximate. The Cass County assessor keeps the parcel record (Cass County website); a licensed surveyor sets the true corners.
Zoning
Cass County zones its unincorporated land, and Plattsmouth, Louisville, Weeping Water each zone the land inside their limits. ParcelSheet shows the use the county assessor lists for the lot and links the county zoning office for the district, the uses it allows and the lot size it needs.
ADU and guest houses
Under Nebraska's county zoning law (Neb. Rev. Stat. 23-114) and each city's zoning powers, local governments can allow an accessory dwelling unit on a lot with a house. Whether a Cass lot can add one depends on its district; the county 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. Cass County is soil survey area NE025, Cass County, Nebraska, last updated September 2026, on Web Soil Survey.
A new or changed septic system in Cass County must be registered with the Nebraska Department of Environment and Energy onsite wastewater program (Title 124).
Setbacks
Setbacks in Cass 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 Plattsmouth, Louisville, Weeping Water for land inside their limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a Cass lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Cass County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for Cass County has 39 panels, the newest effective August 2024. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Cass County?
Open the Nebraska map, type the address, and the parcel outline from the Cass 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 Cass County?
Zoning in Cass County is set by the county for unincorporated land and by each city (such as Plattsmouth, Louisville) 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 Cass County?
Under Nebraska's county zoning law (Neb. Rev. Stat. 23-114) and each city's zoning powers, counties and cities can allow an accessory dwelling unit, and each sets its own rules. In Cass 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 Cass County?
Yes. A new or changed septic system in Cass County must be registered with the Nebraska Department of Environment and Energy onsite wastewater program (Title 124). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area NE025 (Cass County, Nebraska).
What can I build on 5 acres in Cass County?
Zoning in Cass County is set by the county for unincorporated land and each city inside its own limits (such as Plattsmouth, Louisville). 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 Cass County website.
What are the residential setbacks in Cass County (2026)?
Setbacks in Cass 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 Cass County website.
Next to Cass County: Lancaster County, Otoe County, Sarpy County, Saunders County.
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