The self-supplied population may be determined by subtracting the permanent resident population served by public water supply from the total population. The estimated self-supplied population will be too low if nonresidents are included in the population served. When using this technique, vacationers and users of second homes are not considered residents. Resident population estimates may be obtained from county planners or consulting firms who have recently studied developments of second homes in an area. Breakdown of domestic consumptive use pre-1980 and post 1980 fixture implementation.
Consumptive use is estimated for self-supplied and delivered domestic water.
Domestic consumptive use is typically estimated by a percentage of water that is withdrawn and delivered for domestic purposes. Percentage of consumptive use should be based on information obtained from contacts with water suppliers or from references for each state. The largest amount of domestic consumptive use probably is from lawn watering, because most lawn water is evaporated or transpired. Therefore, estimates of lawn watering are useful when estimating domestic consumptive use. Amounts not released are subtracted from water users wastewater-treatment bills.