2006 Water Comprehensive Plan - City of Bellevue

Water BalanceA water balance is an accounting for all water that is produced and/or purchased. Table 4-2shows the water balance format developed by the International Water Association (IWA)and recommended by the AWWA Water Loss Committee, along with the relevant numbersfor Bellevue in 2004. The IWA format has been modified slightly to include a sub-categorycalled “Remainder”; this modification is discussed below.Table 4-2 - Water Balance 2004WaterProducedand/orPurchasedLevel #1 Level #2 Level #3Revenue WaterNon-Revenue WaterBilled AuthorizedConsumptionUnbilled AuthorizedConsumptionApparent LossesVolume(gpd)% of WaterPurchasedBilled Water Exported 1,852,710 10.7%Billed Metered Consumption -Permanent Meters14,786,929 85.6%Billed Metered Consumption -Temporary Meters0 0.0%Billed Unmetered Consumption 0 0.0%Unbilled Metered Consumption 0 0.0%Unbilled UnmeteredConsumption 1 0 0.0%Unauthorized Consumption 0 UnknownCustomer Metering Inaccuracies 0 UnknownKnown Leakage on Mains 0 0.0%Known Leakage on ServiceReal LossesConnections0 0.0%Leakage and Overflows atStorage0 UnknownRemainder 626,480 3.6%TOTAL 17,266,119 100%The water balance allocates the Water Produced and/or Purchased to different categories atthree different levels.The first level simply allocates the Water Produced and/or Purchased to either RevenueWater or Non-Revenue Water. As implied by the names, Revenue Water generates incomewhile Non-Revenue Water does not. This is helpful in understanding what percent of waterproduced and/or purchased generates income for the water utility.The second level splits Non-Revenue Water into the following four sub-categories which areuseful in identifying potential additional revenue sources and identifying the magnitude ofleaks that could be fixed:• Unbilled Authorized Consumption: Includes uses such as water system flushing,firefighting, street cleaning, main testing, main breaks, and reservoir draining andcleaning.4-4