Discussion Paper - Harvard Kennedy School

Thirsty Colonias: Determinants of Water Service Coverage in South Texas

This paper examines the reasons why some poor communities in the Texas-Mexico border region have obtained central drinking water services, and some have not. Identifying some specific determinants of water service coverage in Texas communities, the paper''s conclusions speak to the common global phenomenon of lack of access to drinking water and sanitation services in poor communities.

This study analyzes Texas colonias, unincorporated rural and urban subdivisions near the U.S.-Mexico border lacking basic infrastructure, including paved roads, drainage and, in many cases, utility service. In the mid-1990s, Texas colonias emitted nearly 2 million gallons per day of untreated wastewater into the Rio Grande, the border river. The region comprises the largest concentration of households without basic sanitation in the United States, and it suffers numerous public health consequences related to this problem.

The most common explanation for the absence of public utility service in these communities is that they are both poor and expensive to connect, making them risky revenue prospects for public or private utility infrastructure. I test this assertion. While the analysis bears out that both of these factors - high potential cost of service and low revenue potential - do play some role in determining which communities obtain service and which do not, they are by far not the only important factors.

This study is the first to examine the influence of institutional factors, specifically the characteristics of state-identified "most likely" water service providers, on service coverage among Texas colonias, and I find that these factors are at least equally as important as the cost and revenue factors. For example, colonias within the service territories of non-profit water supply corporations were 42 percent more likely to have obtained water service by 1996 than colonias within the service territory of municipal water systems, and 31 percent more likely to have obtained service than those within regional water districts or county water service territories. The magnitude of the influence of potential water service provider on service coverage is far greater than the magnitude of the influence of income, location in an urban vs. a rural area, population, and other factors.

This finding is consistent with qualitative analyses of water and sanitation service provision in the developing world, where it is difficult to find examples of efficient, large-scale public monopolies serving the poor. I conclude that this apparent difference among service providers has important policy implications for the State of Texas.

In addition, policies designed to address the problem of inadequate water and sanitation services for Texas colonias do not differentiate between urban and rural communities. This analysis indicates that urban and rural water supply are really two separate problems. For example, large rural colonias are more likely to obtain service than small rural colonias, but the reverse is true for urban colonias, which may suffer for their size. Incorporating large populations of low-income ratepayers into existing urban water supply systems may be more of a political problem than an engineering problem. Even when they have similar socioeconomic characteristics, urban and rural colonias appear to face very different challenges to obtaining water service, requiring different policy responses.

While this study examines poor communities in four Texas border counties, its results have implications for extending public services to poor urban, peri-urban and rural communities in other states and countries, as well. Of the 3.9 billion people living in the 25 largest developing countries in 1999, only 84 percent of urban residents and 51 percent of rural residents had access to clean drinking water. Given that many poor households do obtain safe drinking water services, this analysis is a first step at understanding why so many do not. The results indicate that characteristics of potential water service providers are at least as important as characteristics of poor households themselves in determining who obtains service.

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For Academic Citation: Cavanagh, Sheila. “Thirsty Colonias: Determinants of Water Service Coverage in South Texas.” Discussion Paper, 2001-14, Harvard Kennedy School, September 30, 2001.