1.) Please Burn Those Pie Charts of the Amount of Freshwater on EarthYes, as part of understanding Earth systems one should know that most water on the planet is salty or frozen but this graphic is very sticky and counterproductive for water Sustainability. Why? Because it gives the impression that water is a global like food supplies or greenhouse gases. But water supply is Local not Global. So if I choose to reduce my carbon emissions or go vegetarian this (if multiplied) can have ripple effects throughout our global society. If someone in New York turns off their tap when they brush their teeth that is not going to do diddly squat for the water crisis in California let alone some place in Africa. Each watershed has distinct challenges and solutions and more importantly except for a handful of extreme engineering projects their Sustainability is independent from each other. So we do not have a GLOBAL water challenge, the Earth still has the same amount of water it always did, we just have watersheds and regions that have water challenges. Additionally this graphic gives the impression of a supply which could be used up. Water is not used up like other resources, e.g. oil, that supply of freshwater we see is constantly being renewed by the water cycle (mostly with water from the oceans).
2.) Access to Clean Water is NOT an Issue of SupplyThere are currently about 750 million people without access to clean drinking water .1)People and organizations continue to use the greatly outdated 1 billion number which hides the remarkable, if still too slow, progress being made. This is a terrible problem but the issue is not the total supply of water, there is plenty of water. It is a lack of infrastructure and other related problems (see this story about the situation in Ghana ). This problem of clean water is COMPLETELY unrelated to the issues around Sustainability and water that we have in a developed country such as the USA.2)While we can always improve and must remain vigilant. Our tap water is remarkably clean and its wonderful--just check out this map of what the CDC thinks of the rest of the world . Let me repeat. There is not a problem with the total supply of water for direct consumption by humans.3)This is my other issue with that famous pie chart, it gives the impression that there is hardly enough water to drink on our planet. There is plenty of water to drink and more is raining down all the time as long as we collect, treat and distribute it.
Photo by cindy47452  
3.) Plenty to Drink but Enough to Eat?So if there is plenty to drink, why do certain regions of the world such as California have such severe water shortages? In California, as is typical for dry regions around the world, 80% of the water used by people is used for agriculture .4)You may see 40% cited as well which includes all the water which is allowed to stay in rivers and not captured by people. Most of this water is in the wetter, north part of the state, remember what I said about distinct regions… That means our water is not being used up by all of the people who don't turn off the water while they shave instead it goes to crops like cotton, which in Arizona requires covering the field to a depth of five feet of water over the course of a growing season. This is not to trivialize the importance or necessarily question the value of irrigated agriculture, it is HUGELY important (for better or worse) for our modern food system. It is nice to see that agriculture is finally getting recognition  as the primary user of our water. The GLOBAL challenge about water supply is how we can grow enough food if we have to reduce how much goes to irrigated agriculture (or just can't continue expanding it).
4.) Bad Policies are RampantIn general water policy in arid regions is pretty terrible and California is a prime example.5)Interestingly enough Arizona has some of the best water policies, not something you hear often about our state. Water restrictions have finally been passed and they leave out agriculture completely , the biggest consumer! Unfortunately water conservation policies which skip agriculture are not just likely to be ineffective but also be disproportionately born by the poor . Irrigated agriculture largely relies on cheap water so price increases which reflected the actual scarcity of drought years would drive farmers out of business and no one would then be there to use the water that is arriving in already built canals in good years.
So if you live in California and do your best to use very little water, you know that an almond tree or a cow is still drinking (via alfalfa) its fill. My further problem is that any surplus water generated through conservation, will ultimately just end up being used elsewhere in the system. We imagine that if we turn off the tap there will be more water for the poor fish but in reality the only way water is returned to our rivers for nature is through the endangered species act and the courts. 
Photo by Link576  
Photo by Link576  
5.) Individual Action is (almost) FruitlessMisunderstandings and bad policy is common in almost any Sustainability area, so that does not sufficiently explain why I think water is a terrible topic to introduce Sustainability. I feel this way principally because individual direct use is a tiny portion of water usage so changing behaviors will have little to no impact.6)Now for myself I do try and cut my water use wherever possible, but I view this more as part of my general goal of using as few resources as possible and certainly don't consider it a high impact area. Compare this to climate where we directly emit GHG from driving and indirectly from electricity use and diet which can be drastically reduced via behavior changes. For water supply, landscaping is about the only really impactful direct action an individual can take. Now direct action is not the only way to make Sustainable change. Unfortunately effective indirect action seems unlikely to be very helpful due to what I mentioned previously: the regionalism of water issues (e.g. coffee has a big water footprint but it is generally only grown in the tropics with plenty of rain), regional supply being relevant not global (if I save water in Florida I am not going to help California's drought), current bad policies and the path dependence of existing agricultural infrastructure.
Great News! We CAN Achieve Sustainability with WaterI may seem like a negative Nelly but actually being an Arizonan gives me faith that we actually Achieving Sustainability with water, even without some crazy new technology.7)In contrast I believe we are going to need massive technological advances in clean energy to Achieving Sustainability in that area. The great news:
- There is a lot of water and it renews itself every year, for free! We just have to deal with some variability.
- We are getting closer to getting clean drinking water to everyone in the world.
- Water withdrawals are actually falling in the US. 
- There are ways we can use water for agriculture in vastly more efficient ways, which is really the key area when we talk about supply
- There are good, proven policies, from tiered metering to groundwater management strategies which can ensure supplies.
Footnotes [ +  ]
|1.||↑||People and organizations continue to use the greatly outdated 1 billion number which hides the remarkable, if still too slow, progress being made.|
|2.||↑||While we can always improve and must remain vigilant. Our tap water is remarkably clean and its wonderful--just check out this map of what the CDC thinks of the rest of the world .|
|3.||↑||This is my other issue with that famous pie chart, it gives the impression that there is hardly enough water to drink on our planet. There is plenty of water to drink and more is raining down all the time as long as we collect, treat and distribute it.|
|4.||↑||You may see 40% cited as well which includes all the water which is allowed to stay in rivers and not captured by people. Most of this water is in the wetter, north part of the state, remember what I said about distinct regions…|
|5.||↑||Interestingly enough Arizona has some of the best water policies, not something you hear often about our state.|
|6.||↑||Now for myself I do try and cut my water use wherever possible, but I view this more as part of my general goal of using as few resources as possible and certainly don't consider it a high impact area.|
|7.||↑||In contrast I believe we are going to need massive technological advances in clean energy to Achieving Sustainability in that area.|