When someone complains about having low water pressure it is usually at the sink faucet. The first thing to check is if the low water pressure is affecting both the hot and cold water. If both the hot and cold have low pressure the most likely cause is the aerator. Calcium deposits slowly build up in the faucet aerator and reduce the water pressure. A blocked aerator is a very easy thing to fix. To clean out a faucet aerator carefully remove the aerator, clean out any debris and build up on it and put it back on.