A cash crunch for public water utilities is creating an opportunity for the growing for-profit water companies—but it’s one that might drain customers’ wallets. Companies like American Water Works Co. and Aqua America Inc. are finding the time is right to purchase small, troubled water utilities from local governments that are facing political pressure to keep rates low—often by delaying infrastructure upgrades. Acquisitions like these are helping private water companies grow even while per capita water consumption continues its long-term downward trend.