If the problem has occurred suddenly, there may be a break in plumbing. Check all of your faucets to see if it is your plumbing. If all faucets are affected, there may be a nearby main water line break or it could be from an unusually high demand on the system. Check with neighbors to see if they are experiencing a similar problem. If the answer is yes, call the Water System. Otherwise check for signs of a leak and contact a plumber. You can turn off all of your faucets and check your water meter.