Clogged Sprayer Head
One reason sprayers have low water pressure is due to sedimentary buildup throughout the sprayer head. Mainly the sediments and minerals in your water gather in the nozzles of the sprayer head. Deposits might form along the inside of the sprayer as well. To fix this issue, take the sprayer head off by turning it and removing the top portion. Soak the sprayer in a sediment dissolving solution like CLR or any cleaning product made to reduce lime and calcium buildup. Rinse the sprayer thoroughly in clear water, and replace the sprayer head.
Reduced Water in Faucet
If there is reduced water in the faucet as well, several factors are to blame. The first is a partially closed supply line valve, which is underneath your sink countertop. It is on the water pipes leading to the faucet. Turn the valve all the way to the open position, which is counterclockwise on most faucets. Verify that both valves are all the way open. Turn the faucet on, and test it to see if this helps improve water flow.
Clog in Faucet Line
A clog inside the faucet reduces water flow to the sprayer because the sprayer draws water directly from the faucet. It is connected at the base of the faucet. The hose is secured to a connector here. Turn off the water to the faucet by shutting the water pipe valves. Remove the sprayer hose from the connection, and see if anything is lodged inside the faucet. Remove all residue, reconnect the hose, turn on the water and test the faucet.
Diverter Valve Clog
Each sprayer has a diverter valve inside the faucet that sends the water to the sprayer. If this is clogged or broken, the sprayer loses water pressure. Usually, the sprayer receives no water if this part is broken. To fix this issue, take off the faucet handle by unscrewing the retaining nut and pulling it off. Remove the bonnet or dome cap, and lift the spout off the base of the sink. Look for the diverter valve, which sticks out from the faucet base. Remove it by pulling it out and clean it. Rinse the area around the valve, and replace the diverter. Reassemble the faucet, and test for water flow.