AS TO PEAK LOADS 167 



all the domestic services in a system the average rate of output 

 is probably not over 2 or 3 per cent of the combined capacities 

 of the services and meters. Practically speaking, it makes no 

 difference to the water- works system whether an individual con- 

 sumer draws 5 gallons of water in one minute or in ten minutes. 

 It does perhaps make a very little difference whether it is drawn 

 during those hours of the day when heavy drafts are common 

 or in the hours when the normal use is light. 



The peak loads in a water-works system resulting from 

 domestic service are at most only a small fraction of the loads 

 that have to be provided for in connection with fire service. 

 The pipes in the streets, the reservoirs, the pumps, or whatever 

 appliances are depended to furnish the water to meet the peaks 

 must always have capacity greatly in excess of the domestic 

 peak load to meet fire service. 



Further, ordinarily these pipes, reservoirs and pumps are 

 built to meet a certain amount of anticipated future growth, 

 and until otherwise required that margin is also available to meet 

 peak loads. 



On the other hand, it is undoubtedly a fact, when the analysis 

 is carried to a logical conclusion, that the capacity in all these 

 structures that must be provided is somewhat greater because 

 of the domestic peak loads. While the proportion is relatively 

 small, it is one of the elements that influence cost, and the cost 

 of the service is somewhat greater because of these fluctua- 

 tions. 



The situation differs from the electric situation in the rela- 

 tive importance of the peaks. In the electrical business these 

 peaks are large and meeting them is costly to the works. In 

 the water works business they are relatively small and easily 

 provided for. Under these conditions, the demand charges for 

 domestic water consumers become so small relatively that it 

 is hardly necessary to try to separate them, and they may be 

 more conveniently and with all needed accuracy divided into 

 the two remaining classes. That is to say, they may be divided 

 between the service charge and the output charge. 



This is the method that has been followed by the New 



