If you have a Moen shower head and the water pressure isn't what it used to be, there are a few things you can do to increase the water flow. First, check to see if the water flow is restricted by sediment build-up. If so, clean out the shower head with vinegar or a commercial shower head cleaner. If that doesn't improve the water pressure, disassemble the shower head and check for mineral deposits on the internal parts. Soak these parts in vinegar or CLR overnight, then rinse and reassemble the shower head. Once you've done all of this, if your Moen shower head still has low water pressure, it may be time to replace it with a new one.