How to Read Your Flood Risk Analysis

After entering an address, you'll receive a comprehensive flood risk assessment. This guide explains each section of the analysis report and how to interpret the results.

Property Overview

The first section displays fundamental property characteristics that affect flood risk.

Address: The full street address you searched
Building Size: Total square footage from HCAD records
- Shows "Vacant Lot" if no structures exist
- Displays "(Override)" if you entered custom square footage in Property Characteristics
- May show multiple structures if the property has more than one building
Elevation: Height above sea level in feet from USGS data
- Higher elevation generally means lower flood risk
- Measured relative to NAVD88 datum (North American Vertical Datum)
FEMA Flood Zone: Official flood zone designation
- Click "View all flood zones" to see definitions of all FEMA zones
- High-risk zones (A, AE, V, VE) require flood insurance for federally backed mortgages
- Moderate-risk zones (X-Shaded) have 0.2% annual flood chance
- Minimal-risk zones (X-Unshaded) are outside the 500-year floodplain
Overall Risk: Comprehensive risk rating from Very Low to Very High
- Combines elevation, flood zone, and historical flood patterns
- Updates in real-time when you use the flood simulator

Risk Assessment Outputs

This section provides detailed technical metrics from the flood risk model.

Risk Rating: Detailed risk level with confidence interval
- Typically shown with 95% confidence level
- Updates to show "Property flooded" badge when simulator shows flooding
Flood Depth: Predicted water depth at the property
- Measured in feet above ground level or foundation
- Includes error band (e.g., ±0.5 ft) to show uncertainty
- Shows "0 ft" if property would not flood at current water level
Water Surface Elevation (WSE): Water level relative to sea level
- Measured in feet using NAVD88 datum
- Shows "N/A" if data is not available
- Available when using flood simulator
Area Inundated: Flooded area surrounding the property
- Measured in acres within a 500-meter radius circle
- Also shown as percentage of the 500m radius area
- Helps assess neighborhood flood risk, not just individual property
Nearest Bayou Stage: Flood threshold for closest waterway
- Shows the bayou name and water level at which it begins flooding
- Measured in feet
- Shows "N/A" if no bayou is within monitoring range
Depth-Damage Estimate (HCAD Valuation): Dollar amount of estimated flood damage
- Based on HCAD's official building value
- Uses U.S. Army Corps of Engineers depth-damage curves
- Shows $0 if property is not flooded or is a vacant lot
- Accounts for mitigation features (flood vents reduce damage up to 15%)
Depth-Damage Estimate (Neighborhood Comparison): Alternative damage estimate
- Based on neighborhood replacement costs or $154/sqft estimate
- Provides second opinion when HCAD valuation may be outdated
- Also uses USACE depth-damage methodology
Analysis Method: Computational model used
- Shows model name (e.g., "COG Bathtub", "HAND Model")
- Describes the methodology (e.g., "USGS Elevation + FEMA Zones")

Flood Simulation Results

This section shows whether the property would flood in the modeled scenario.

Initial Analysis: Models Hurricane Harvey-level event (10-foot water level)
- Shows whether flood waters would reach the structure
- Displays safety margin if property stays dry
Simulator-Updated Results: When you use flood simulator controls
- Results update in real-time as you adjust water levels
- Shows current scenario based on your simulator settings
If Property Would Be Flooded:
- Shows flood depth in feet
- Displays severity level: Minor (0-1 ft), Moderate (1-3 ft), or Severe (3+ ft)
If Property Would Be Safe:
- Shows safety margin (distance above water level)
- Indicates property is above the flood level

Flood Risk Recommendations

The final section provides specific action items based on the property's flood risk profile.

Flood Insurance Requirements:
- Indicates if flood insurance is required for federally backed mortgages
- Recommends insurance even for moderate-risk areas
Mitigation Measures:
- Suggests specific flood protection improvements
- May include elevating utilities, installing flood vents, or improving drainage
Due Diligence Steps:
- Recommends additional research for property buyers
- May suggest reviewing flood history, surveyor reports, or elevation certificates
Updates with Simulator:
- Recommendations update based on your flood simulator settings
- Provides scenario-specific advice

Tips for Understanding Your Results

Compare Both Damage Estimates

Review both HCAD and Neighborhood damage estimates. If they differ significantly, the neighborhood estimate may be more accurate for recently renovated or older properties.

Consider the 500m Radius

"Area Inundated" shows flooding in your neighborhood, not just your property. High inundation percentages may mean road access issues even if your home stays dry.

Understand Flood Zones

Click "View all flood zones" to understand FEMA designations. Remember that 25% of flood claims come from low-to-moderate risk areas, so zone X doesn't mean zero risk.

Use Simulator for Scenarios

The initial analysis shows a Harvey-level event. Use the flood simulator to explore different storm intensities and see how recommendations change.