Ninety-Five Per Cent Is a Distance: Spare-Parts Travel, Maintenance Funds, and the Availability of a Village Hand Pump

For a hand pump with 180-day mean time between failures, 95 percent availability allows a 9.47-day mean repair time, crossed at about 80 km parts distance without local stock; a fund of about 203 USD per year covers repairs at 20 km, village parts stocking raises availability to 0.997, and downtime at 80 km costs about 366 USD per year in collection time. SIMULATED, NOT MEASURED.