Clogged
Check Your Aerator
If you have especially hard water, aerators become clogged with hard water buildup, a common cause of low water pressure in kitchen fixtures. Clean your aerator for a quick and easy DIY fix. Remove the aerator from the faucet using pliers and a towel (to prevent scratching).
To restore water flow due to a clogged aerator, use pliers to remove the aerator from the faucet, scrub it with an old toothbrush and rinse in water. If the aerator is severely clogged, soak it overnight in vinegar, wash it, and reattach it to the faucet.
A fast drop in only one faucet means there's a problem with the faucet. Rapid low pressure affecting one area of the house may mean a corroded pipe issue. An abrupt water pressure drop affecting the whole house may mean a water main break (municipal water) or a well pump problem (well water).
If it's a sink, the most common causes are a clogged aerator or clogged cartridge. You can remove both using a pair of pliers, and clean them with a mix of water and white vinegar to scrub away limescale buildup.
Touch faucets have a screen below the sink. The debris screens and flow restrictors required for aerators and showerheads can clog, resulting in greatly reduced flow rates.
Sometimes faucets get clogged, broken or dislodged, and this can block the flow of water. To check if the problem is with your faucet, try other faucets, like bathroom faucets. Check to see if the water is coming out of them. If they are working fine, it means that the problem is in the faucet.
Open your main water valve.
Find the valve and check to see if it's completely open. Opening a half-shut valve is one of the quickest ways for increasing home water pressure. Sometimes the main valve is turned off accidentally during routine repairs and maintenance without the homeowner's knowledge.
If you want to increase pressure, you can try cleaning the aerator, rinsing the filter, or flushing the water supply lines. You can also fine-tune the shut-off valves to increase and decrease pressure. When you're finished, your faucet should run like new!
The cartridge is located inside the faucet and controls the flow of water. If it becomes clogged, it can restrict water flow, resulting in low water pressure. The cartridge may be clogged because of a build-up of minerals, soap scum, or other debris.
Low Water Pressure from Faucets and Fixtures
Water pressure problems could be as simple as faulty faucets and fixtures. If you're experiencing low pressure in a specific area, check for clogging or corrosion that could be slowing water flow.
Reasons for Low Water Pressure Only in the Kitchen Sink
Clogged aerator. Blocked or broken cartridge. Impaired water lines. Pipe leaks.
These air bubbles usually find their way to the highest points in your plumbing system, lower water pressure, and inhibit the flow of water through the pipes. Air in the water piping system can cause rust and corrosion. Rusted pipes weaken, and the rust can drop sediment into your water.
If only one faucet is having problems, you may simply be dealing with a clogged aerator. You should also see if the faucet's stopcock is open, as this too may be causing it to shut off. However, if you're having a problem with multiple faucets, you should probably move on to step two…
Water pressure drops in cold weather because of frozen pipes or high demand. Frozen pipes can burst, causing costly water damage. Other causes of low water pressure include buildup or partially closed valves. Check water valves and individual faucets to find the source of the problem.
Please keep in mind that all new faucets since 1994 are restricted to conserve water per EPA code mandates. Older faucets had no restrictions. Beyond intentional flow restriction, new installations can sometimes have reduced flow if the lines are not flushed prior to installation of aerators or shower heads.
Indoor faucets usually have aerators at the tip. This small but valuable part consists of a mesh responsible for the consistent water flow. Since it controls water pressure, it reduces water splashing in the sink.
Since the EPA limits water flow at 2.2 gpm, most modern faucets now come with a pre-installed aerator that limits the flow to 2.2 gpm while also infusing the water stream with air to reduce splashing.