Household water use between November and March is generally the time period that San Antonio Water System (SAWS) uses to determine our monthly sewer charge for the next year. To conserve water and keep your utilities cost down, reduce water use as much as possible. About 40 percent of residential water use is for maintaining yards and gardens. If you have a sprinkler system, put it on its manual setting until next spring. Water lawns only about every three weeks and flowerbeds as needed when the top 2 to 3 inches of soil is dry. Moisture evaporation is slower in cooler weather.