Faucet Aerator: Function, Types, and Replacement Guide

A faucet aerator is a small screen-and-mesh device that threads onto the tip of a faucet spout and mixes air into the water stream to reduce flow rate and prevent splashing.

Aerator (Faucet) diagram — labeled parts, dimensions, and installation context

What It Is

An aerator is a small fitting, usually less than an inch in diameter, that screws onto the end of a faucet spout. It contains one or more fine mesh screens and a flow restrictor. As water passes through, air is drawn in and mixed with the stream. The result is a soft, bubbly flow that uses less water than an unrestricted stream while still feeling adequate for rinsing and washing.

Aerators are one of the least expensive plumbing components in a home, but they play a meaningful role in water conservation. In the United States, WaterSense-labeled aerators reduce kitchen and bathroom faucet flow to 1.5 gallons per minute (gpm) or less. Standard faucets without aerators can exceed 2.2 gpm. In high-use households, the savings add up over a year.

Aerators also collect sediment and mineral deposits over time, which is why a faucet that once had strong pressure may gradually weaken — the aerator screen is likely clogged.

Types

Standard aerators are the most common. They thread onto external faucet threads (male-threaded spout) or insert into internal faucet threads (female-threaded spout) using a cache/recessed design. Flow rates typically range from 0.5 gpm to 2.2 gpm.

Dual-thread aerators fit both male and female spout configurations with an adapter and are useful for replacement when the original spout thread type is unknown.

Laminar flow aerators do not mix in air — they produce a clear, non-aerated stream used in medical and laboratory settings to prevent mist that could carry pathogens.

Swivel aerators allow the spout to pivot or rotate, common on kitchen faucets.

Where It Is Used

Aerators are standard on bathroom sink faucets, kitchen faucets, and utility sink faucets. They are not used on bathtub spouts, outdoor hose bibs, or faucets designed to fill containers quickly where flow rate is more important than conservation.

How to Identify One

Unscrew the tip of the faucet spout by hand or with slip-joint pliers wrapped in a cloth to avoid scratching. Inside you will find a small assembly: a housing, rubber washer, one or more mesh screens, and a flow restrictor disk. If the screens are discolored, caked with white mineral deposits (calcium scale), or visibly clogged with debris, the aerator needs cleaning or replacement.

Replacement

Aerators are inexpensive (typically $3–$15) and require no tools beyond pliers for stubborn fittings. Before purchasing a replacement, remove the existing aerator and note the thread size (most common are 15/16 in. male or 55/64 in. female) and the desired flow rate. Soaking a clogged aerator in white vinegar for 30–60 minutes dissolves most mineral deposits and often restores full function without replacement.

Aerator (Faucet) — FAQ

What does a faucet aerator actually do?

An aerator mixes air into the water stream as it exits the faucet. This reduces the overall flow rate — measured in gallons per minute — while maintaining enough pressure for effective rinsing. It also breaks the stream into fine droplets that spread out rather than splash, which keeps water in the sink instead of on the counter.

Why is my faucet pressure low after I cleaned the sink?

Low pressure after cleaning is almost always a clogged aerator. Cleaning products, dislodged sediment, or disturbed pipe scale can wash into the aerator screen and block flow. Unscrew the aerator from the spout tip, rinse the screen under running water, and soak it in white vinegar for 30 minutes to dissolve any mineral deposits. Reassemble and test.

Do I need a permit to replace a faucet aerator?

No. Replacing an aerator is a minor maintenance task that does not require a permit anywhere in the United States. It is a tool-optional job that homeowners can complete in a few minutes. No water shutoff is required — you are only working at the faucet tip, not touching supply lines.

How much does it cost to replace an aerator?

Aerators cost between $3 and $15 at any hardware store, depending on thread size, flow rate, and brand. If you hire a plumber to replace one, expect to pay a service call fee ($75–$150) that far exceeds the part cost — most homeowners handle this themselves.

What flow rate aerator should I choose?

For bathroom faucets, 0.5–1.0 gpm is sufficient for handwashing. For kitchen faucets, 1.5–2.2 gpm is more practical for filling pots and rinsing dishes. WaterSense-certified aerators cap at 1.5 gpm and meet EPA efficiency standards. If your water pressure is already low, avoid going below 1.0 gpm or the flow will feel too weak.

How often should I clean or replace my aerator?

In areas with hard water (high mineral content), aerators may need cleaning every 3–6 months. In areas with soft water, annual inspection is usually enough. If you notice reduced flow, spray pattern changes, or visible buildup on the screen, clean it immediately. Replace it if the screen is physically damaged or corroded.