Rainwater Storage Simulator
Simulate a tank over ordered rainfall periods, showing captured water, overflow, demand coverage and backup-water needs.
- 1Explore the example
- 2Edit your assumptions
- 3Compare & export
Loading the worked example…
Your working data
Edit cells directly or import a CSV. Download “Input CSV” for the required column names. Up to 200 rows; scroll the table sideways for additional fields.
Detailed analysis
Exports include all results, regardless of the search filter. The HTML report includes assumptions and source data; use your browser’s Print command for PDF.
Chart shows the first 20 rows; negative values use a warm color. Click table headers to sort.
Compare up to four scenarios
Capture the current inputs, change assumptions and capture again. Scenarios are included in downloaded projects.
What this model includes
Rows are processed in their entered order. Each period’s rainfall arrives before demand; this coarse model cannot reproduce storms or daily shortages inside a period. Non-potable water budgeting only.
Import and save safely
CSV imports use your current assumptions. Project files restore assumptions, rows and saved scenarios. No automatic saving: download a project before closing this page. Imports are limited to 10 MiB and 200 rows. Calculations run in your browser; the site’s advertising and analytics follow its privacy policy.
Using Rainwater Storage Simulator
Simulate a tank over ordered rainfall periods, showing captured water, overflow, demand coverage and backup-water needs.
- Review the preloaded example and the model limits before entering real data.
- Adjust collection area (m²), collection efficiency (%), tank capacity (liters), initial storage (liters).
- Edit the period rows or import a CSV using the Input CSV column template.
- Open Results & chart to inspect details, sort columns and filter rows.
- Capture alternative scenarios, then download a project, result CSV or printable report.
Example
The worked example includes January, February, March, April. Change the first collection area (m²) setting and compare the result with a saved baseline.
Questions & answers
What does Rainwater Storage Simulator calculate?
Simulate a tank over ordered rainfall periods, showing captured water, overflow, demand coverage and backup-water needs.
What are the important limitations?
Rows are processed in their entered order. Each period’s rainfall arrives before demand; this coarse model cannot reproduce storms or daily shortages inside a period. Non-potable water budgeting only.
Can I continue my work later?
Yes. Save a project JSON file and reopen it with Import CSV / project. It contains the working data, assumptions and up to four scenarios. Nothing is saved automatically.
What CSV columns do I need?
period, rain, demand. Download Input CSV for a compatible example. CSV imports keep your current assumptions.
Are these example figures current industry benchmarks?
No. They are illustrative values to demonstrate the model. Replace them with figures appropriate to your situation.
Related tools
A useful next step for your task.
Everyday CalculatorsIrrigation Zone SchedulerCalculate zone watering durations and group zones into runs that stay within an entered supply-flow limit.
Everyday CalculatorsGarden Bed Soil CalculatorEstimate soil volume for a rectangular raised bed and bags to buy.
Everyday CalculatorsSeasonal Garden CalendarCreate crop-specific sowing, transplant and estimated harvest dates from your chosen seasonal anchor and succession intervals.
Everyday Calculators2026 Tax Refund EstimatorEstimate your 2026 federal income tax refund or balance due with the new IRS brackets, standard deduction, tips, overtime, car-loan and senior…
Help improve this tool
Report a problem or suggest an improvement
Describe the issue without pasting private tool input. Feedback goes to our admin inbox.