If you have pressure issues here are some possible causes and solutions.
1) Hardness clogging up faucets: Faucet screens (especially ones that you use a lot of warm/hot water) will get scale build-up from hard water. Showerheads will also get clogged with the scale from hot water. To correct the issue – soak screens/showerheads in white vinegar for an hour and then scrub with a toothbrush. To correct the issue long-term, install a water softener that will remove the hardness before it enters your home.
2) New installation of a water softener: Especially if you are on well water and/or have galvanized pipes in the house, the installation of a water softener will start to clean the pipes in your home. Sometimes the resulting sediment will clog up faucet screens/showerheads. You can test by removing a screen and cleaning with a toothbrush. This is a temporary issue and should clear up within a week.
3) Media in your water softener has failed: There are several causes of failing media in your water softener. If you are on city water and your provider didn’t provide a system with carbon to filter out the chlorine, the chlorine will damage the resin. When damaged by chlorine, the water softener resin will turn into goo and will clog the system and/or get pushed into the pipes in your home (building up in your faucets). If it has pushed into your home you may also be getting a yellowish discolor to your water.
If you are on city water and haven’t kept up with regular maintenance (replacing the carbon when the chlorine has broken it down); then you could have the resin degrade at 5-7 years after installation depending on water usage and chlorine levels.
If you are on well water and the PH on your well has dropped below 7.0 or you have sulfur on your water – that can both cause damage to the media. Most resins on well systems will last more than 10 years and some systems as much as 25 years.
4) Sediment filter/carbon filter is clogged: Many well systems include a sediment filter (to remove sand) or carbon filters to remove smaller contaminants. Some of these filters do not backwash or clean themselves and they need to be removed and cleaned off or replaced every 90-24 months depending on the filter and the amount of contamination. To test – remove the filter (or bypass it) at your home and see if the water pressure increases.
5) Well pressure tank/bladder/pump: If there is a very acute (not gradual) drop in water pressure on a well, it is best to contact a reputable well company to look at your system. It could be leaking back into the well, the pump may not be performing properly or you may have issues with your pressure tank or bladder (which pressurize the water in your home).