Flood Water Category Calculator

Classify flood water to plan drying and demolition. Adjust for sewage, chemicals, and stagnant time. Download reports, share results, and document job decisions today.

Assessment inputs

Optional label for reports and records.
Source strongly influences initial contamination risk.
Sensitive occupancy raises response requirements.
Longer exposure increases microbial growth risk.
Deeper water spreads contaminants across materials.
Warm water can accelerate biological activity.
Contamination indicators
Direct sewage makes Category 3 likely.
Include fuel, solvents, pesticides, or unknown chemicals.
Mud, silt, trash, algae, or suspended solids.
Persistent musty or foul odor suggests contamination.
Soil contact increases microbial load and uncertainty.
Leaves, compost, manure, or animal waste.
Affected materials (select all)
Porous materials raise complexity and may require removal in higher categories.
Notes appear in the PDF report for documentation.

Example dataset

Scenario Source Hours Depth (cm) Indicators Estimated category
Office leak Supply line 8 3 No odor, no debris Category 1
Kitchen backup Appliance discharge 36 6 Odor present Category 2
Basement seepage Groundwater 60 15 Debris, soil contact Category 2
River flood River overflow 20 25 Debris, soil contact Category 3
Sewage incident Sewage backup 5 10 Sewage confirmed Category 3

Examples are illustrative. Actual conditions can vary by site and regulations.

Formula used

The calculator assigns a contamination score using weighted indicators. The score starts with a base value from the selected water source, then adds points for time, depth, temperature, and observed hazards.

  • Base score (source): potable/controlled sources start low; river/coastal sources start higher; sewage starts highest.
  • Time thresholds: +1 after 24 hours, +1 after 48 hours, +1 after 72 hours.
  • Depth thresholds: +1 above 10 cm, +1 above 30 cm.
  • Hazard flags: sewage +6, chemicals/oil +3, debris +2, odor +2, soil contact +2, organic waste +1.
  • Material complexity: +1 if multiple porous materials are affected.
  • Category mapping: score ≤3 → Category 1, score 4–7 → Category 2, score ≥8 → Category 3.

How to use this calculator

  1. Choose the most accurate water source based on inspection.
  2. Enter exposure time, depth, and approximate temperature.
  3. Tick any contamination indicators you can confirm on site.
  4. Select the materials that were exposed to floodwater.
  5. Click Calculate category to view results above the form.
  6. Use Download CSV or Download PDF to attach to job files.
Tip: If the source is uncertain, record observations in notes and treat the response conservatively.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.