The Intercontinental Hotels Group plans next year to give all 4,700 of its hotels access to an online tool that lets managers track how much energy and water they are using.The group hopes to use the system to cut water use by 12% over the next three years in water-starved areas like California.During a multimillion-dollar renovation three years ago, the Hotel Bel-Air in Los Angeles installed a filtering system to reuse bathroom water from a dozen hotel suites to irrigate its 12 acres of gardens.The Loews Santa Monica Beach Hotel plans to install a system to recycle about 70% of the water used for its laundry operation. The project, which is expected to be installed by mid-December, will cost about $96,000, after water and gas rebates, according to hotel officials.Hotel officials expect the investment will pay for itself in 17 months.