Pick a placeFor any place on Earth, Droply shows how much water rain, fog and air can give there, how much solar power a system needs for it and what it costs – compared with tap water.
Free, no sign-up. A first estimate from climate data – measure on site before you buy.
What a result looks likeMannheim, Germany · Watering a community garden
See the setup ↓Litres: average over the year – less in dry months, more in wet ones, a tank evens it out. Prices: guide values incl. VAT, as of September 2026, excluding installation, maintenance and running costs.
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Choose a place →You see how much rain, fog, humid air and sun come together there, which building blocks work and roughly what they cost.
In the builder you put your system together yourself: bigger tank, swap rain for fog, more solar power – the result changes straight away.
Rainwater harvesting · Water tank
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Mannheim, Germany
Precipitation760mm per year= about 760 litres per m² of roof a year
In Mannheim, rainwater is the natural route for a community garden: roofs collect rainfall and a tank bridges dry summer spells. Drinking water is not the goal here.
Symbolic image · Photo: Eva Bronzini · Pexels
Singapore
Precipitation2,890mm per year= about 2,890 litres per m² of roof a year
Singapore combines abundant rain with a high drinking-water standard. Rain collection can contribute; it needs treatment – a UV-C lamp that kills germs with ultraviolet light, and remineralisation that gives the very soft rainwater its minerals back – plus its own solar power for both.
Symbolic image · Photo: Ravish Maqsood · Pexels
Alto Patache, Chile
Fog yield, measured6L per m² of net per day (annual mean)
On the coast near Alto Patache the resource is not rain but the camanchaca – the coastal fog that rolls in from the Pacific. Fog nets – fine meshes on which fog droplets get caught and drip down – collect the water; for drinking water it then needs treatment.
Symbolic image · Photo: Kindel Media · Pexels
Dubai, United Arab Emirates
Sun6.1kWh per m² per day (solar energy falling on one square metre)
Dubai has strong sun and humid summers, but dry winters. An air-to-water generator – a device that condenses water from humid air, much like a dehumidifier – powered by solar is therefore a seasonal example, not a promise of constant yields.
Symbolic image · Photo: Kadir Avşar · Pexels
Gobabeb, Namibia
Fog yield, converted0.08–0.27L per m² of net per day (annual mean)
Near Gobabeb, rain is scarce, but fog regularly arrives from the Atlantic. A fog net with treatment and storage fits this example; the local fog yield must be measured on site.
Symbolic image · Photo: Francesco Ungaro · Pexels
Figures from the map’s data: rain and sun from ERA5, the climate reanalysis of the EU’s Copernicus Earth observation programme – mean 2011 to 2025, per cell of about 50 × 50 km. Fog yield: measured at known fog measuring points, or converted to an annual mean from the yield per fog day. Sources per measuring point
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Values of the 0.5° grid cell, mean 2011–2025 – the same as on the map.
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A roof or other surface collects rainfall and channels it into a tank. No rain, no water – but also no electricity.
A mesh hung vertically; fog droplets catch on it and run down into a gutter. Only works where fog passes through regularly.
A machine that draws in air and cools it until the water in it condenses – like on a cold bottle. Needs warm, humid air and a lot of electricity.
A container that bridges the days when nothing comes in. Without storage the best source is useless the moment it pauses.
Carbon with a huge internal surface binds odour, taste, chlorine and organic compounds. Removes neither germs nor salts.
Short-wave light destroys the genetic material of bacteria and viruses as the water flows past. Works only on clear water and removes no chemicals.
One to four solar panels with a plug, on a railing or terrace. Feeds at most 800 W into the home and can be connected without an electrician (Germany).
Hoses deliver water drop by drop straight to the root. Loses far less to evaporation than watering or sprinkling.
Get a rough idea of what rainwater, a tank or a solar panel can deliver and cost where you live – no prior knowledge needed.
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Good enough for a first estimate, not for a building plan. The climate figures are averages over cells of about 50 × 50 km for the years 2011 to 2025; a valley or a coastline can differ considerably. A real installation needs measurements on site and a check by a professional.
Climate figures: ERA5, the climate reanalysis of the EU’s Copernicus Earth observation programme – calculated from measurements and weather models. Places: Natural Earth and GeoNames. Prices in the builder: reference values from common online offers, as of September 2026 – not quotes. Every source, assumption and known weakness is listed on the “Sources & method” page.
Because many people work on it every day: waterworks, pipes and treatment plants. On average a person in Germany uses 122 litres a day (BDEW, 2024). 1,000 litres of drinking water cost €2.06 on average, €4.77 including wastewater (Destatis, 2025). Depending on where you live it can be much more or less.
Not yet. Droply calculates and explains; the prices in the builder are reference values, not offers from us. If you would like to hear when that changes, write to us via the contact form.
The calculation runs in your browser and is not transmitted. The map loads map tiles from OpenFreeMap, which sees your IP address. For “Weather now”, the coordinates, rounded to about one kilometre, go to our server. Your settings and drafts stay in your browser. The only thing stored is what you send yourself through a form.
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