Cities in the Western United States are growing faster than in other parts of the country. Cheap land and a strong regional tradition emphasizing property rights over government regulation have directed much of this growth outward, creating sprawling cities and far-flung suburban communities that threaten to undermine the long-term viability of the cities themselves. Limited water supplies and deteriorating air quality are among the obstacles to further growth in the region that are fueling efforts to curb sprawl. A 1973 Oregon law requiring localities to address the sprawl problem is among the models that states and cities throughout the West are studying as they grapple with fast growth. But in Portland, meanwhile, critics blame the landmark urban growth boundary with causing too much density.