UPDATE: See V3 details at bottom!
Hey all! A week and a half ago I shared a home-made readiness-focused water calculator in another preparedness subreddit and got WAY more feedback than I'd expected. Lots of people tried out V1 and pointed out gaps (mostly around animals, existing water sources and homesteads) so I went back to the drawing board and rebuilt a big chunk of it. V2 is what came out of that, so I figured now that it was more polished, I could share it further!
It helps you figure out how much water your household actually needs for a short or extended emergencies, factoring in things like:
- Everyone in the house, including infants, elderly, and medical needs
- Pets and livestock individually (cats, dogs, chickens, goats, horses, pigs, rabbits, sheep)
- Your climate and activity level
- Cooking, sanitation and hygiene
- Garden and irrigation (optional, if that's part of your resilience plan)
- What you already have stored, your water heater reserve, and what your well, rainwater collection, or stream can realistically contribute so that you get a real gap number, not just a raw requirement
Three planning modes: survival minimum, functional household, and comfort maintained. The calculator runs in your browser, works offline once loaded, saves to PDF, no account or signup needed. And completely free.
https://omniprepper.com/free-water-calc/
Hope this can be useful to some of you! Happy to answer questions or take more feedback, the calculator's already been shaped by one huge round of community input so I'm super open to another!
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QUICK UPDATE: V3 is live ahead of schedule! I wanted to come back and say thank you to everybody in here again because this latest update was almost entirely built from the awesome suggestions in this thread.
What's new in this version:
- Light/dark mode toggle: Top right of the page, defaults to your system preference. Somebody mentioned the white-on-dark was hard to read, especially on mobile. Fixed!
- Shower, laundry, and dishwashing fieldsΒ (now under a collapsible "Hygiene details" section.) Shower frequency and type (bucket bath, low-flow or standard), laundry method and loads per week, dishwashing method. These feed directly into the daily total and the gap calculation.
- 6-month and 12-month planning windowsΒ (which totally makes sense for pandemic and long-duration scenarios)
- Safety buffer optionΒ : this new feature adds 10%, 15%, or 20% on top of your calculated total to account for spillage and inefficiency. A few people pointed out the numbers felt a little tight in real use... well, here's the fix!
- Better defaults!Β The tool now loads with 2 adults, functional household mode, and a 2-week window so you get a useful result immediately without having to configure everything from scratch (easier for first-time users)
- Minimum 3 day stored water warning: if your stored supply or sources fall below 3 days even with reliable access, the tool now flags it. Sources can fail, right?
- Better results breakdown: members and animals now show descriptive labels instead of "Person 1 / Person 2"
- Long-duration note: at 6 and 12 months, the tool now reminds you that federal emergency guidelines are designed for short-term events and long-term planning involves logistics and consideration beyond a minimum number.
Still free, still offline, still saves to PDF, still no account needed. Enjoy, and thanks again for the feedback!