Low Water Pressure at Sink Faucet — Causes and Fixes

Low water pressure at a single faucet is almost always caused by a clogged aerator, a partially closed supply valve, or a clogged cartridge. If all fixtures in your home have low pressure, the issue is with the municipal supply or pressure regulator and requires a plumber.

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   Step 1: Clean the aerator

   The aerator is the small screen screwed onto the end of the faucet spout. Unscrew it counterclockwise by hand or with padded pliers (wrap jaws with tape to avoid scratching the finish). Disassemble it by separating the housing, screen mesh, and flow restrictor. Rinse all parts under running water and use a toothbrush to scrub mineral deposits from the screen. Soak in white vinegar for 30 minutes for heavy scale buildup.

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   Step 2: Check the supply valves

   The hot and cold supply valves under the sink should be fully open (turned counterclockwise until they stop or handle parallel to the pipe). A partially closed valve dramatically reduces pressure. This is easily overlooked after plumbing work or if the valves were accidentally bumped.

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   Step 3: Check for a kinked or partially blocked supply line

   Flexible braided supply lines under the sink can kink or partially collapse after years of service. Inspect both hot and cold supply lines for bends or kinks. A kinked line is easy to spot — replace it with a new stainless steel braided line.

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   Step 4: Remove and inspect the cartridge

   In hard water areas, cartridges and internal ports can clog with mineral deposits. Remove the cartridge (see the Faucet Dripping guide for instructions) and soak it in white vinegar for 1–2 hours to dissolve scale. Also inspect the valve body ports — use a small pick to clear any mineral deposits from the inlet holes.