Independent utility
Built to make a storage assumption inspectable
Rain Tank Planner is an independent, free rainwater planning tool. It exists because a yearly rainfall total cannot show whether a tank carries useful water through the dry sequences that matter.
What this site does
The planner runs the same stated demand against several tank capacities, one day at a time. It uses either a long NASA POWER rainfall series or daily data supplied by the visitor. It then exposes the tradeoff between demand coverage, reliable days, retained water, overflow, and shortfalls. The tank-sizing guide includes reproducible examples for comparing those outcomes.
For an existing tank or barrel, the rain barrel watering calculator checks how long the currently stored water lasts and estimates static gravity pressure at the entered water levels.
The calculation is ordinary deterministic code, not a language-model answer. The equations, event order, source boundaries, and recommendation rule are published on the method page.
Editorial principles
- Show assumptions. Inputs and limitations should remain visible instead of being hidden behind one “ideal size.”
- Prefer primary sources. Technical claims link to NASA, government, or similarly direct documentation where practical.
- Separate estimates from approvals. The tool does not substitute for local plumbing, structural, water-quality, fire, legal, or engineering advice.
- Correct transparently. Material method changes will update the method page and its date rather than silently changing the meaning of results.
- Avoid fabricated precision. Grid rainfall and uncertain demand should be explored as scenarios, not presented as a property-specific guarantee.
Funding
The service is free to use. Advertising is currently inactive. If ads are introduced, they will be visually separate from calculations and will not determine the result. Supplier selection is independent of commission. When an approved affiliate programme is enabled, its links carry an “Affiliate link” disclosure beside the link and may earn a commission on a qualifying purchase. Ordinary unlabelled links earn no commission. Affiliate relationships do not change the calculations or create paid rankings.
Corrections and contact
To report a reproducible calculation problem, broken source, accessibility issue, or factual correction, email hello@raintankplanner.com. Include the page and enough non-sensitive detail to reproduce the issue; do not send a home address or a rainfall file containing personal information.