Clean water is what really matters

My favorite measure of socioeconomic progress – I might in fact argue it’s the only one that matters – is increases in life expectancy. The gap between life expectancy in the United States and Southern Africa is staggering, and the same can be said of the difference between the US today and in 1900. In both cases the difference is roughly 30 years. For all its importance, however, there’s little consensus on where life expectancy gains actually came from. We’ve known for decades that life expectancy follows something called the “Preston curve” with respect to income:

Life expectancy vs. income; each dot is one country

The relationship is usually described as log-linear, but it’s pretty close to a steep initial curve joined to a flatter one at a kink point. Getting over that initial hump near $6000 (2005 PPP dollars) is pretty crucial. Based on the curve, economists have often argued that the real action in life expectancy is driven by income gains – give people more money and they take better care of themselves, moving right along the curve.

Anybody who’s read the stuff I post here, or just talked to me about traveling to developing countries, knows I’m fairly skeptical of that approach. Clean water clearly has a huge impact on people’s daily lives, and I’m convinced very few people have any idea how important it is. Americans who travel to poor regions commonly talk about “traveler’s diarrhea” and relate it to eating street food or just a strange diet. Their afflictions are in fact caused by intestinal parasites in the drinking water, and eating any kind of cooked food is fairly low-risk relative to drinking from the tap, brushing your teeth with tapwater, or even eating (rinsed) fresh vegetables. I’m singling out my own countrymen here just as an example – outside of a select group of middle-class people in the developing world, very few people anywhere understand how dangerous dirty water is. My instinct is that major health gains, at least with respect to oral-fecal disease transmission, have come from public policies that imposed higher standards from the outside, rather than people learning how to protect themselves from contaminated water and then gaining the income to afford it.

So it’s no surprise to me that David Cutler and Grant Miller were able to attribute over half of the drop in mortality in the early 20th-center US to better water treatment. But I’d argue their approach might understate the benefits of better sanitation. As I’ve pointed out repeatedly, better health, especially early in life, lead to outsized gains in income and wellbeing down the road. If that holds for waterborne illnesses as well then in addition to “shifting the Preston Curve up” – improving mortality at all income levels – water quality improvements can give people more income so that they can move along the curve as well, and ideally past that crucial $6000 hump.

I’ve seen a lot of encouraging efforts to promote better water quality in poor countries. My fellow UM graduate student Jess Hoel is working on a project to scale up home chlorination, for example. But most seem focused on individual behavioral change, and I’m doubtful that can succeed. In the US, at least, we sidestepped the tricky problem of public health education and compliance entirely, and imposed clean water from the top down. As I speculated in the title of this post, I think that’s the kind of intervention that can make a huge difference.


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3 Responses to Clean water is what really matters

  1. James says:

    Hi Jason –

    I’m a friend of Adam Schwarz’s and reader of your blog. I really enjoy your posts which are always very thorough, well researched, and engaging.

    I manage clean water, sanitation, and hygiene (WASH) projects in Africa and share your assessment of the core need for WASH in development and your skepticism of approaches focused behavior change.

    That said, even if we increased funding two or three-fold to infrastructure installation we still have an uphill climb. 50% of water projects fail within 5 years. In my opinion, that’s the most important statistic you need to know to understand the water crisis in the developing world (sanitation and hygiene are a bit different). We simply haven’t figured out a reliable way to deliver water services to the poor.

    Those groups that are looking at this issue closely have identified long-term financial planning, coordination with governments, charging for water, the development of accountable water management institutions, and partnership with the private sector as key factors in the success of a water project. There are programs like Triple-S (Sustainable Services at Scale), WASHCost, Water for People, WaterAid, and IRC doing some great work on this problem. WaterHealth International is an interesting company (an Acumen Fund portfolio company) that installs micro water utilities and maintains them for 10 years or more.

    Thanks for starting the discussion on this issue.

  2. Jason Kerwin says:

    James –

    That 50% failure rate is troubling, but it raises a couple of questions. Do you know if it covers all water projects (including irrigation, damming, etc) or is it for sanitation/drinking water alone? Also, I wonder how much of the failure hinges on trying to get people to change their behavior as opposed to inability to maintain infrastructure, etc.

    I couldn’t agree more about charging for water. What people rarely realize is that usually discounted or free water is going to agriculture rather than toward, say, drinking water for the poor; this leads to huge waste. I’d like to hear more about your own organization, and your take on what other people are doing, when you get a chance.

    As an aside, my instinct is that the path to success in providing clean water is urbanization – it’s hard to see how you can lay down the infrastructure needed to make it work with people spread out in rural communities. The septic systems that make this stuff work in the US seem pretty costly.

    – Jason

  3. James says:

    Hi Jason,

    Thanks for the response. On the 50% failure rate, that refers to drinking water programs. I’m not sure if research has been done to identify the contributions of various factors to this statistic. Reports I’ve read suggest that leading drivers include a) lack of sufficient financial planning (i.e. no money to cover repair or replacement), b) absence of locally-available spare parts or trained technicians to repair the infrastructure, and c) over-drawing the aquifer. So I think you’re right on with regards to inability to maintain infrastructure being the leading cause here.

    I’m with you on pricing of water and think this is really critical to addressing water issues throughout the world – from California to Kenya. However, I would clarify that most Africans don’t use borehole (or otherwise “safe”) water to water crops, so I don’t think the problem is a market distortion in a shift away from household use toward ag. But there is over consumption at the household level when water is given away for free and that can lead to waste and water shortages. But most critically, water pricing is important because communities need the revenues to support long-term repair and replacement of infrastructure. Of course, that requires effective and ethical governance by water committees or service providers to ensure the funds are not misappropriated for other purposes when the water infrastructure is functioning as it should (myopia is a real issue here).

    Your point on urbanization is a great insight for someone who’s not focused on water specifically. Laying pipes, and pumping and treating water is extremely expensive. In California, 20% of the state’s electricity is directed toward pumping and treating water. It’s simply not possible to get piped water to many rural areas in Africa in the near future.

    There is real promise that some micro utilities, like WaterHealth can bridge the gap in rural regions between boreholes (which are inconvenient and can be unreliable) and piped water (which will never reach there – it’s a pipe dream, no pun intended). I predict that we’re going to start to see some of these smaller, decentralized water treatment and piping schemes scale in the near future. These systems might represent a “skip” in the historical progression of water service delivery which has largely followed the path of expanding networks from a massive, central water treatment plant (much like cell phones “skipped” land lines avoiding massive infrastructure costs). We’ve seen that these utilities can sustain themselves as a business and I think we’ll see these reach scale in the coming decades.

    The big question, for me, is how to bring sanitation to the developing world quickly and at a high quality. In many ways, this is a bigger problem and a more complicated one since water-based sanitation suffers from the same issues of infrastructure costs which you identify and because scaling sanitation involves a high degree of behavior change. Most people feel the need for clean water. They understand that. It’s not the same for sanitation and that’s a huge barrier.

    What’s the future look like for serving the 2.6 billion people without sanitation? I really can’t tell you but there is some very early stage promise around using the biosolids for fertilizer and energy to support the installation of sanitation facilities. We’ll see how that goes. It’s a huge problem and a significant driver of disease.

    Glad to continue the conversation and keep up the great posting. I really enjoy this blog.


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