San Francisco Water Woes


  1. Sustainability problem: Unsustainable water sourcing for the San Francisco Bay Area
  • California has faced record-breaking droughts putting stress on existing water sources.
  • Existing water resources cannot be used at current rates without depleting long-term capacity.
  • Most of the water resources available to the city are far away and used by other municipalities. Water is not collected or controlled locally


  1. The technology: Advanced Fog Collection

“How to get fresh water out of thin air” MIT News [ ]

  • Fog collection is an ancient practice, but recent advances in materials science can make fog collection more efficient for use in densely populated areas.
  • San Francisco is surrounded by seawater, but does not have much fresh water. However, it experiences fog clouds that derive from evaporated seawater that blows inland from the Pacific Ocean.
  • Unlike existing desalination methods, no energy is required to collect fog, as it takes advantage of the sun’s energy to desalinate the water.  Fog collection methods are affordable and require little maintenance. They are easy to install on both small and large scales.
  • Innovators at M.I.T. have optimized the material characteristics and mesh-size of fog-catching nets to produce more water in a smaller space, and reduce evaporation off the nets back into the air. These new methods can extract up to 10% of the water in fog and triple the collection capabilities of existing methods. 


  1. Organizational stakeholders:
  • City Water Authority
  • Consumers
  • Property owners and developers
  • Environmental organizations


  1. Steps to deploy the technology:
  • Step 1: Identify areas that receive the most fog and relevant building codes.
  • Step 2: Identify pilot partners to install roof top fog collectors and MIT researchers and patent holders willing to pilot their designs and integrate them into a water system. Partnerships may be made with those who have or are looking to build green roofs, as water can be collected and distributed on the roof without creating new piping systems.
  • Step 3: Launch pilot with willing partners and optimal locations identified in Steps 1 and 2.

2 thoughts on “San Francisco Water Woes

  1. I think this is a very interesting technology, and one that I am sure will be used along coasts in the future. One reservation, or rather question, I have regarding this though, is how this technology is connected to purifying systems. If these fog collectors are installed on rooftops, then the purifying systems need to be quite small. In cities in California, where I would dare to say air quality is quite good, this may be very feasible. However, what about in cities that have terrible air pollution and where fog may contain more contaminants? Is this technology already feasible for such (more polluted) areas and if not, what is being done to do this?


  2. This is really interesting and could have some potential applications beyond just fog capture – in terms of air quality and pollution as well as re-use and re-application of other types of waste water into clean and purified drinking water. The article posted mentioned applications in agriculture, which would be huge considering how influential agricultural practices are on climate change.
    class june 16, 2016 – uni mst2135


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