Faucet Has Low Water Pressure? Fixes
When faucet low water pressure turns a normal hand wash into a weak trickle, the cause is usually small and close to the faucet itself. A clogged aerator, a half-closed shut-off valve, or sediment in a supply line can cut flow dramatically while the rest of your plumbing works fine. Before you call a plumber or replace the faucet, work through the simple checks in this guide. Most homeowners find and fix the problem in under an hour with no special tools, and the steps below are ordered from the easiest fix to the deeper checks, so you can stop as soon as the flow returns.
Is It One Faucet or the Whole House?
The first question decides everything else. Test the affected faucet on both hot and cold. Then test a nearby faucet, a bathroom faucet, and a shower or tub. If only one faucet is weak, the blockage is almost certainly at that faucet: its aerator, cartridge, or supply lines. If both hot and cold are weak at one faucet but other fixtures are fine, suspect the faucet itself rather than the water heater or main supply. If only the hot side is weak at several fixtures, the problem may be at the water heater, such as sediment buildup or a failing shut-off valve on the heater line.
If every fixture in the house is weak, look at shared components. Confirm the main shut-off valve is fully open, because a valve left half-closed after a repair is a common and embarrassing cause. Check whether a water softener is in bypass or needs service, and look at the pressure regulator near the main line if your home has one. Normal household pressure is usually 40 to 80 pounds per square inch. A simple screw-on pressure gauge that attaches to an outdoor hose bib costs under 20 dollars and tells you in seconds whether house pressure is actually low or whether the problem is local to one fixture. Also check with neighbors or your water utility. If the whole street is affected, the cause is a municipal issue, and no faucet repair will fix it.
Clean or Replace the Aerator
The aerator is the small mesh screen at the tip of the faucet spout, and it is the most common cause of low pressure at a single faucet. It mixes air into the stream and catches sediment, mineral scale, and debris. Over time that screen clogs, and flow drops even though supply pressure is normal. To clean it, unscrew the aerator by hand or with pliers wrapped in cloth to protect the finish. Note the order of its parts: screen, washer, and flow restrictor. Soak the parts in white vinegar for 30 minutes, scrub gently with an old toothbrush, rinse, and reassemble in the same order.
Test the faucet with the aerator removed before you reinstall it. If flow is strong without the aerator and weak with it, you have found the problem. A cleaned aerator often restores full flow, but if the screen is torn, corroded, or heavily scaled, replace it. Universal aerators cost 5 to 15 dollars and come in standard thread sizes, so bring the old one to the store to match the thread. While the aerator is off, run the faucet for a few seconds to flush loose debris from the spout. For broader faucet help, see our faucets and fixtures hub and our step-by-step guide to fixing a leaky faucet, which covers removing handles and cartridges safely.
Check the Shut-Off Valves
Under the sink, the hot and cold shut-off valves control flow to the faucet. If either valve is only partly open, flow drops. Turn each valve fully counterclockwise to open it, then back it off a quarter turn, which is standard practice to prevent seizing. Older multi-turn valves can fail internally even when the handle turns. The rubber washer inside can swell, break apart, or block the passage, cutting flow while the handle feels normal. Quarter-turn ball valves are more reliable, and if your old valves are corroded or stiff, replacing them during this repair prevents repeat trouble.
Check the valve outlets and supply lines for kinks as well. Flexible braided supply lines can kink if they are pushed against the cabinet wall or tangled with cleaning supplies. Straighten any sharp bends and confirm the lines are not pinched. If a supply line looks swollen, cracked, or corroded at the connection, replace it rather than reusing it. Braided stainless supply lines cost 10 to 20 dollars each and are a cheap insurance policy against a burst line. While you are under the sink, look for dampness, drips, or white mineral trails at connections. A slow leak at a valve can reduce pressure slightly and cause cabinet damage long before you notice a puddle.
Flush the Supply Lines and Cartridge
If the aerator and valves check out, sediment may be trapped deeper in the faucet. Turn off both shut-off valves, disconnect the supply lines from the faucet inlets, and point each line into a bucket. Turn the valve on briefly to flush the line. If water flows strongly into the bucket but weakly through the faucet, the blockage is inside the faucet. If flow from the line itself is weak, the line or valve needs replacement. Catching the water in a bucket also lets you see sediment, rust flakes, or grit that would otherwise keep clogging the faucet.
Next, remove the faucet cartridge or stem, following the same careful disassembly used for a leak repair, and inspect it for debris and mineral buildup. Soak the cartridge in vinegar, rinse it, and flush the faucet body by turning the supply on briefly with the cartridge removed and a towel over the opening. Reinstall the cartridge in its original orientation, reconnect the lines, and test. In homes with hard water or old galvanized pipes, this flush often restores flow dramatically. If the cartridge is scored, cracked, or swollen, replace it with an exact match. A new cartridge costs 15 to 60 dollars and often fixes both pressure and drip problems at once.
Fix Low Pressure in Kitchen Sprayers
Kitchen faucets with pull-down or side sprayers have extra parts that can restrict flow. A clogged spray head, a kinked pull-down hose, or a stuck diverter valve can make the main spout weak while the sprayer works, or vice versa. Start by unscrewing the spray head and cleaning its screen the same way you cleaned the aerator. Check the hose under the sink for kinks, especially where it passes through a weight or guide. Pull the hose out fully and let it retract smoothly. If the hose is kinked or the weight is stuck, repositioning it often restores flow immediately.
The diverter valve, which sends water to the sprayer when you press its trigger, can also stick partly open. When it sticks, water divides between the spout and sprayer, and neither gets full pressure. On many faucets the diverter is a small part inside the faucet body that can be cleaned or replaced for 10 to 25 dollars. Consult your faucet manual or manufacturer support for the exact location. If your kitchen faucet is older and several of these parts are worn at once, compare the repair cost against a new faucet. Our kitchen faucet buying guide explains flow rates, spray options, and finishes so a replacement, if needed, is an upgrade rather than a guess.
When Low Pressure Signals a Bigger Problem
Some pressure problems point beyond the faucet. A sudden drop across the whole house, discolored water, or the sound of running water when no tap is open can signal a broken pipe or a major leak. Turn off the main supply and check your water meter. If the meter moves with all taps closed, water is going somewhere it should not. Look for wet spots in the yard, damp drywall, or a warm spot on a slab floor. These symptoms need a plumber promptly, because hidden leaks cause mold and structural damage quickly. Similarly, if your home has old galvanized steel pipes, internal corrosion narrows them over decades, and pressure falls gradually at every fixture. No aerator cleaning will fix that, and repiping is the long-term answer.
A failing pressure regulator can also cause house-wide low pressure or pressure that swings wildly. Regulators typically last 10 to 15 years. If a gauge shows pressure below 40 psi at the hose bib with the main valve fully open, or pressure fluctuates when fixtures run, have the regulator tested. Replacement usually costs 250 to 450 dollars professionally. Finally, remember that low-flow fixtures are sometimes working as designed. Modern faucets are limited to 1.5 gallons per minute or less by federal standards, and some homeowners mistake an efficient faucet for a broken one. Compare flow with a similar modern faucet before assuming a fault. If you need help diagnosing a stubborn case, our guide to touchless versus touch faucets also covers sensor and solenoid issues that can restrict flow in electronic models.