1. Rainwater Harvesting: Collecting rainwater from rooftops and other surfaces and storing it for future use.
2. Desalination: Removing salt from seawater through processes such as reverse osmosis and electrodialysis.
3. Surface Water Treatment: Treating water from rivers, lakes, and reservoirs by removing impurities, sediments, and harmful microorganisms.
4. Groundwater Pumping: Extracting water from underground aquifers through wells and boreholes.
5. Ice Melting: Collecting and melting snow and ice from glaciers, icebergs, or polar regions.
6. Fog Catching: Using nets or other structures to capture water droplets from fog.
7. Condensation: Collecting water vapor from the atmosphere through condensation and filtering to remove impurities.
8. Greywater Recycling: Treating and reusing household wastewater for irrigation, cleaning, or other non-potable purposes.
9. Spring Water Collection: Collecting water from natural springs or seeps.
10. Reverse Osmosis: A water purification process that uses a semipermeable membrane to remove impurities, salts, and minerals.
11. Distillation: Boiling water and collecting the condensed steam, leaving behind impurities and contaminants.
12. Ion Exchange: A water softening process that removes ions such as calcium, magnesium, and sulfate by exchanging them with sodium or chloride ions.
13. Filtration: Passing water through a porous barrier to remove suspended solids, particles, and microorganisms.
14. Ultrafiltration: A high-pressure filtration process that removes particles, bacteria, and viruses smaller than those removed by conventional filtration.
15. Ozonation: Treating water with ozone gas to disinfect and remove organic matter.
16. Chlorination: Adding chlorine to water to disinfect it and kill bacteria.
It's worth noting that the method used to obtain fresh water may depend on factors such as location, water source availability, energy requirements, and local conditions.