Blog · October 14, 2026 · California
Colusa County Flood Zone Map, California
FEMA's free flood maps and the Colusa County parcel viewer, used together for property near Williams.
Main page: Colusa County, CA GIS & Parcel Viewer (official map link, Colusa County facts and neighboring maps).
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Before you buy a house in Williams, add on to a barn near Arbuckle, or price a lot along Sacramento River, check the Colusa County flood zone map. You can check it yourself for any Williams address in a few minutes.
Next: FEMA's search tool, the zone labels you'll see for Colusa County, and how the parcel record confirms which tract you're on.
Look up the Colusa County flood zone map step by step
FEMA's official flood maps for Colusa County are free at the FEMA Flood Map Service Center. Search returns the effective FIRM panel for the spot in Colusa County, plus any pending changes FEMA has posted. For an irregular lot near Grimes, the National Flood Hazard Layer viewer is easier to use; zoom to the piece of ground near Grimes and click. Switch to the Colusa County ArcGIS parcel map and track down the same piece of ground near Grimes. Laying the county parcel outline beside the FEMA shading shows whether a homesite near Grimes sits above or inside the zone.
Finding the tract on the Colusa County map
Colusa County publishes its parcels on the Colusa County ArcGIS parcel map, which runs on an Esri ArcGIS web map, free to use for a lot in Arbuckle or a piece of ground near Grimes. Use the search box for an address in Arbuckle or a parcel number, or simply zoom in and click a piece of ground near Grimes. Our Colusa County, CA page keeps the official link and the maps next door to Grimes in one place.
Zone A, AE and X in plain English
On the FIRM covering Colusa County, zones that start with A or V are Special Flood Hazard Areas, meaning FEMA estimates a 1-percent annual chance of flooding. A surveyor working near Arbuckle uses the base flood elevation printed for AE zones; unnumbered A zones do not have one. Shaded Zone X around Arbuckle is moderate risk, between the 1-percent and 0.2-percent annual chance lines. Clear, unshaded X near Arbuckle is outside the 500-year floodplain.
Creeks, rivers and low ground in Colusa County
The Colusa County landscape includes Sacramento River, and that's where flood questions cluster. Don't assume a piece of ground near Grimes is clear as its road frontage sits high. Small streams and ditches near Arbuckle may not be studied in detail, which is why it is worth walking the ground after a heavy rain.
Flood insurance and building rules in Colusa County
Insurance is the practical stake for a Colusa County buyer. When a structure near Grimes falls inside an A or V zone and is financed by a regulated or federally insured lender, a flood policy becomes a loan condition, provided the community near Arbuckle takes part in the National Flood Insurance Program. For a Colusa County home in shaded or unshaded X, insurance is a choice, not a mandate, although some lenders require it anyway. When a Colusa County homesite is on a rise inside a mapped zone, the titleholder can ask FEMA for a Letter of Map Amendment (LOMA), typically backed by an elevation certificate from a surveyor who works in Colusa County. Placing fill on low ground near Arbuckle typically needs a floodplain permit; the county floodplain administrator can say what applies.
Seller questions about flood history
Request any past flood claims history for a Colusa County property before closing; it tells you more than the map alone. An agent working in Colusa County can quote flood coverage once you know the zone for the lot near Williams.
Neighboring maps around Colusa County
Colusa County borders Butte County, Glenn County, Lake County, Sutter County, and Yolo County, and each keeps its own parcel map and records. Every map bordering Colusa County is listed on our California directory.
Colusa County, CA: common questions
What does Zone AE mean on a Colusa County flood map?
Zone AE on a lot in Grimes is a mapped 100-year floodplain with a base flood elevation, so mandatory insurance rules apply to federally backed mortgages.
Where do I get an elevation certificate in Colusa County?
A licensed surveyor or engineer prepares it, and the building office serving Grimes may already have one on file for newer construction.
What is a base flood elevation for a Colusa County property?
For a Colusa County property in Zone AE, the base flood elevation marks how high the 100-year flood is expected to rise; elevation certificates in Colusa County are measured against it.
Is there a floodplain layer in the Colusa County ArcGIS parcel map?
Check the layer list in the Colusa County ArcGIS parcel map; if Colusa County includes a floodplain layer, confirm the zone on FEMA's map anyway.
Do I need a permit to build in the floodplain near Grimes?
Building in a Special Flood Hazard Area near Grimes typically needs a floodplain permit and may require elevating the structure, so check with the county floodplain administrator.
Open the official Colusa County, CA parcel map Colusa County in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.