I have a well system and have low water pressure and or pressure drops when using the shower and a faucet is turned on, toilet flushed or washer is on. The pump is 1 hp, I have a accumulator tank with the pressure set at 38 psi. The pump on off is 40-60 psi. Measuring the pressure at the accum. Tank it stays between 40 and 60 psi. When I measure the pressure on the faucet on a sink in the garage the pressure goes as low as 25 psi when using multiple water sources: two showers, shower and clothes washer/dish washer and so on. The pump performs at > 10 gpm and supports a sprinkler system with a usage of just under 10 gpm per circuit. The inlet line is 1 inch to 3/4 inch to 1/2 inch lines to each water point. I have in line filters and have the same effect whether the filter element is installed or removed. There are no signs of a kink and I do not know how to check for a blockage. I do not understand the pressure loss at the house and not at the tank. Any suggestions?