SLIP OF SMALL METERS 85 



domestic meter for one day may be assumed to consist of passing 

 200 gallons of water, more or less, in about two hours, the whole 

 time being made up of many short intervals during the day. 

 During the remaining twenty-two hours no water will ordinarily 

 be flowing. If the service pipe and plumbing are perfectly tight, 

 no water will pass during those twenty- two hours; if there is a 

 leak of such size that the water lost by it will turn the meter, 

 then the meter will register the flow throughout the twenty-four 

 hours, and all the water passing will be recorded, except that there 

 may be some slip in the meter at a low rate. If there is a leak 

 in the service or plumbing which allows water to escape, but in 

 amount so small that it does not serve to move the disc or piston 

 of the meter, then the amount of water lost by such leakage in 

 the twenty-two hours when the piston or disc is not moving will 

 be entirely unrecorded. Probably no meter in ordinary service 

 will register a flow of less than 100 gallons in twenty- two hours. 

 Many meters in actual service will allow much larger quantities 

 to pass without registering. It is probable that the plumbing 

 in every house has leaks at times, through defective washers in 

 the faucets or automatic valves which permit the loss of water 

 in amounts too small to be recorded. In some houses such loss 

 is always taking place. In the aggregate the amount of this 

 unrecorded leakage from plumbing is large. It probably fur- 

 nishes the greatest single reason why the amount of water 

 registered by meters never approximates closely the total quan- 

 tity of water furnished by the system. 



Water lost in this way is running at a steady rate through- 

 out the twenty-four hours, and increases but slightly the peak 

 load of the plant. It can, therefore, be supplied at the lowest 

 relative cost, and for the purpose of this estimate should be 

 reckoned at the lowest rate charged for any water that is 

 sold. 



The amount lost per service will range from nothing to 

 loo gallons per day, and occasionally to much larger quantities. 

 Assuming an average of 50 gallons per day per service at a mini- 

 mum price of 10 cents per 1000 gallons, the value of water so 

 lost amounts to $1.82 per service per annum. 



