By Bloomberg Among the environmental worries posed by hydraulic fracturing, including the release of methane into the air and contamination of groundwater, one has recently escalated: the concern that the enormous quantities of water used in fracking will leave parts of the country parched. In 2012, fracking consumed some 50 billion gallons of water – water that many communities can ill afford to spare. New practices can make fracking somewhat less thirsty, however. States should see that drilling companies are encouraged to use them. Each fracking site needs 2 million to 4 million gallons of water, to create sufficient pressure to fracture oil- and gas-containing rocks deep underground. When fresh water is used, it may be diverted from other users, including farms, manufacturing plants and households. There's not always enough to go around; 55% of the wells fracked since 2011 are in drought areas. One way to minimize fracking's drain on fresh water is to substitute, as much as possible, water that's already been used to frack other wells. After fracking, 10% to 50% of the water flows back up through the oil or gas well and is typically disposed of through injection into deep wells, a practice that has been linked with minor but troubling earthquakes. If it is instead cleaned of chemical additives as well as metals and minerals from deep underground, it can be reused. Frackers can also use brackish water from aquifers or municipal and industrial wastewater. Some are even beginning to frack not with great quantities of water but with a foam that contains nitrogen, carbon dioxide and relatively small quantities of water. Some of these options even make fracking cheaper. Regulators need to ensure these alternative practices are consistently adopted. Pennsylvania has the right approach. Before withdrawing water in that state, drillers must win approval for a water-use plan that discloses how much water a well will use, from where and what effect that will have on local sources. To be approved, these plans must include wastewater recycling. Other states – including Kentucky, which exempts frackers altogether from its water-withdrawal rules, and Texas, which allows unlimited withdrawals from groundwater – should follow Pennsylvania's lead. By making approval for fracking contingent on responsible water practices, states can drive even greater innovation – perhaps to the point where frackers come to operate without using any water at all. Gasfrac, a Canadian company, has been using liquefied petroleum gas in gel form to fracture shale, which so far is relatively expensive. But as the technology improves – and water grows harder to come by – operators may find it to be the most attractive strategy.