Planning tool with sourced ranges; not engineering, health or financial advice. Rain and tap water first; air water is a backup layer.

1. Where and who

Choose a climate station or enter temperature and humidity, then your home type, people, roof area, air-conditioners, stored water and how much water each person uses.

2. Physics

See the dew point, the water held in the air, whether dew will form on a surface of a given temperature, and how a night of radiative cooling compares with the literature.

3. Build your stack

Switch on the water sources you could use (roof rain, AC condensate, dehumidifier, machines, sorbent, solar still, dew sheet, fog net), set their sizes and read low and high litres per day, cost per litre, electricity and space.

4. Drought-day countdown

See how many days your stored water lasts at your lowest supply, by consumption tier, with a red warning under three days.

5. Your plan

Pick a 72-hour, 14-day, 90-day, 12-month or 3-year community plan, see it as a timeline, download it as a calendar file, print the checklist, copy a share link or save it on this device.

This planner needs JavaScript for its calculators. The five steps in plain text: (1) note your local temperature and humidity, how many people live with you, your roof area, air-conditioners and stored litres; (2) work out the dew point, and remember that dew only forms on a surface colder than it, typically up to about 0.3 litres per square metre per night and usually less; (3) add up roof rain first, then AC condensate and other air-water sources, as low and high litres per day; (4) divide stored water by the daily shortfall at your lowest supply: under 3 days is red; (5) set dated milestones for 72 hours, 14 days, 90 days, 12 months and 3 years. Read the full written guide at manilaopenhouse.com/blog. Ranges, not promises. Condensate, dew and rain are not drinking water until treated and tested.