Seems like a build up on calcium deposits that are clogging up the faucet. To test this disconnect one of the flex lines going to the shutoff valves to the faucet. Open the valve and place the flex line into a bucket. If there is alot of water flow then something in the faucet is clogged. There are alot of small orifices in the faucet that the water must pass through and these are easily clogged with buildup. Disassemble the faucet and clean