After installing the device, the toilets will use 1.5 fewer gallons per flush.
So each year, the town will save
10,000 (people) * 365 (days in a year) * 8 (flushes per person a day) * 1.5 (gallons per flush saved)
= 10,000*365*8*1.5= 438,000,000 (gallons a year)
Answer: The town will save about 44 million gallons of water each year