The San Antonio Water System is installing digital meters that can monitor water usage by the hour. SAWS installed the 300,000th Advanced Meter Infrastructure unit on Tuesday. The plan is to replace all 610-thousand customer meters by the end of next year, about a year sooner than originally expected. The new meters allow both SAWS and its customers to track their water usage on an hourly basis instead of once a month. The utility says the constant monitoring will make it easier to notice a leak quickly.