Drinking Water compliance

I received 100% of drinking water supply from water treatment works with free chlorine of 0.89mg/l and total chlorine of 1.78mg/l at the reservoir, while from water treatment works free chlorine is 1mg/l and total is 2mg/l.  Currently they reduce supply of drinking water from 100% to 20% from the water treatment works to reservoir ,  free chlorine and total chlorine now is higher at the reservoir free is 2.2mg/l and total is 2.2mg/l as well. While free chlorine and total chlorine from the water treatment works still the same: free chlorine is 1mg/l and total is 2mg/l. What is the cause of high level of chlorine while supply reduce from 100% to 20%?