Grip the plastic aerator tip and turn it counter-clockwise by hand. If it comes off easily, run the faucet directly into a cup for ten seconds at full blast. If it takes less than 15 seconds to fill that cup, your aerator was clogged — cleaning will fix it. If it takes longer than 15 seconds even without the aerator attached, you have a supply line or pressure regulator problem that cleaning won’t solve.
I’ve cleaned aerators on every faucet in my 1970s house, and this test has saved me from chasing the wrong fix more than once. Low water flow has multiple causes, but a clogged aerator is the only one you can solve in ten minutes with vinegar and a toothbrush.
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When aerator cleaning actually solves your problem
Aerator cleaning restores water flow at a single faucet by removing mineral deposits and sediment from the screens. You’ll notice:
- Flow is weak or comes out in uneven spurts
- Water sprays sideways instead of straight down
- Flow was normal last month but has gradually slowed
If water is weak at every faucet in your house, the aerator isn’t your problem — that’s a main supply or pressure regulator issue, and you should call a plumber. The diagnostic test confirms this before you start disassembling anything.
The EPA WaterSense standard caps faucet flow at 2.2 gallons per minute, which means even a small amount of debris creates noticeable pressure loss. That 2.2 GPM benchmark translates to a practical test: a standard cup (8 ounces) should fill in about 10 seconds at full flow. If it takes more than 15 seconds with a clean aerator, your flow rate is below spec.
What you’ll need
Tools:
- Adjustable wrench or channel locks (if the aerator won’t unscrew by hand)
- Old toothbrush or small soft-bristle brush
- Smartphone (to photograph the disassembled parts)
- Measuring cup (to verify flow rate after cleaning)
Materials:
- White distilled vinegar (or CLR for heavy buildup — about $4)
- Small bowl or cup
- Towel (to lay out small parts and prevent loss down the drain)
Optional:
- Replacement aerator ($5–$10 if yours is cracked or the gasket is dry)
- Water hardness test strips ($5–$10 for 50-count pack, measures PPM)
- Teflon tape (to wrap wrench jaws and avoid scratching chrome)
Step 1: Remove the aerator
Most aerators unscrew by hand — grip the ridged plastic housing and turn counter-clockwise. If it’s stuck from mineral buildup, wrap a small piece of cloth or Teflon tape around the metal collar and use an adjustable wrench. Turn gently. Aerators cost $5 to replace; faucet bodies cost $150. If you meet significant resistance, stop and soak the base with vinegar for 20 minutes, then try again.
For cartridge-style aerators (common on pull-down kitchen faucets), grip the entire metal collar at the spout tip rather than just the plastic insert.
Step 2: Lay out the parts in order
Aerators contain three to five small pieces: a threaded outer collar, one or two mesh screens, a plastic flow restrictor or mixer, and a rubber gasket. Disassemble over a towel spread across the counter — it keeps you from losing tiny parts, and the white background makes the screens easier to see.
Take a photo with your phone of the parts laid out in the order they came apart. You’ll need this reference when you reassemble. The screens have a specific orientation; installing them backward reduces flow even after cleaning.
Step 3: Soak the screens in vinegar
Place the metal screens and plastic mixer in a cup of white vinegar. Let them soak for 30 minutes for light buildup, or up to two hours for heavy white crust. Vinegar dissolves calcium, magnesium, and lime — the minerals in hard water that clog aerator holes.
For stubborn deposits, use CLR instead of vinegar — follow the label instructions, and do not mix it with bleach or other cleaners.
Step 4: Brush the screens and rinse
After soaking, use a soft toothbrush to scrub both sides of each screen, paying attention to the underside where debris collects. Rinse under running water. Hold the screen up to a light — you should see light pass through every hole. If any remain blocked, return the screen to the vinegar for another 30 minutes.
The plastic mixer often has small slots or channels on the interior — brush those too. I’ve found sediment packed into mixers that looked clean from the outside.
Step 5: Inspect the gasket
The rubber gasket or O-ring sits between the aerator body and the faucet threads. Wipe it with a damp cloth but do not scrub it. If the gasket is cracked, flattened, or feels brittle, replace it. A bad gasket will leak after reassembly no matter how well you cleaned the screens. Replacement aerator kits at hardware stores include spare gaskets for $2 to $5.
Step 6: Reassemble in the correct order
Refer to your phone photo and stack the parts exactly as they came apart. The most common order is: inner mixer → gasket → fine screen → coarse screen → threaded collar. Hand-tighten only — aerators use plastic threads that strip easily. Snug is enough. If water drips from the base after you turn it on, the gasket is misaligned, not undertightened. Unscrew, reseat the gasket, and try again.
Step 7: Test and verify flow
Turn the water on slowly. Check for leaks at the aerator base and confirm that flow is strong and even. Run the objective flow test: fill a standard 8-ounce cup at full blast. At the EPA standard of 2.2 GPM, the cup should fill in about 10 seconds. If it takes 15 seconds or longer, either you missed a clogged section or the screens are installed backward — remove the aerator and recheck.
Faucet maintenance: how often to clean aerators
Cleaning frequency depends on your water hardness, which varies widely by region. The USGS water hardness data shows that much of Texas, South Florida, and parts of the upper Midwest have water hardness above 200 parts per million — enough to re-clog an aerator every few months.
How to test your water hardness:
Buy water hardness test strips at a hardware store for $5–$10 (50-count pack). Dip a strip in tap water and compare the color to the chart. Readings above 180 PPM indicate hard water; above 250 PPM is very hard. This number tells you how aggressive your cleaning schedule needs to be.
Recommended cleaning schedule:
- Soft water (0–60 PPM, common in Pacific Northwest and parts of New England): once per year
- Moderate hardness (61–180 PPM, most of the Southwest and Midwest): every 6–9 months
- Hard water (181–250 PPM, Texas, Arizona, South Florida): every 3–6 months
- Very hard water (above 250 PPM): quarterly
Decision framework:
If your aerator clogs more than twice per year despite regular cleaning, you have hard water and should consider installing a whole-house water softener or scheduling quarterly maintenance. I tested my Cleveland water at 210 PPM and moved to a quarterly cleaning cycle — it’s faster than re-cleaning the same aerator every eight weeks.
If you’re renting, treat this as preventive faucet maintenance — hard-water staining or reduced flow becomes a fixture-damage dispute when you move out. I cleaned the aerators in my last rental twice a year, took photos, and never had a deduction from my deposit.
When to replace instead of clean
Replacement makes sense if:
- You’ve cleaned the same aerator three or more times in six months
- The gasket is cracked or the threads are stripped
- You want to upgrade to a lower-flow aerator to reduce water bills
- Screens are corroded or physically damaged
Aerators cost $5 to $20 depending on the brand. I keep a spare standard aerator in my tool drawer — if I’m cleaning the same one for the third time in four months, I just swap it out.
Troubleshooting weak flow after cleaning
Flow improved but still not normal:
Your aerator may be rated for lower GPM than you expect. Older aerators flowed at 5–8 GPM; modern plumbing codes require 2.2 GPM or less. A 2.2 GPM aerator that’s partially clogged feels weak; a clean 2.2 GPM aerator also feels weak compared to what you remember. Check the side of the aerator for a flow rating stamp.
Flow is fine but water sprays unevenly:
The screens are installed backward or out of order. Disassemble, refer to your photo, and reinstall with the fine screen closest to the spout opening.
Cleaned thoroughly but flow is still low:
Remove the aerator completely and run the water. If flow is strong without the aerator, the aerator itself is damaged and needs replacement. If flow is still weak, the problem is upstream — check the shut-off valve under the sink (it may be partially closed), or call a plumber to inspect the supply line.
When to call a professional
Aerator cleaning is as low-risk as plumbing work gets, but these scenarios require a plumber:
- Water pressure is low at multiple faucets — indicates a main supply, pressure regulator, or check valve problem
- The aerator won’t unscrew after moderate force — risk of damaging the faucet body; a pro has better tools and can replace the faucet if needed
- Water leaks from the faucet base (not the aerator threads) after cleaning — likely a cartridge or valve seat issue inside the faucet body
- You’re a renter and your lease requires landlord approval for fixture work — notify maintenance first
I won’t force a stuck aerator. Replacing a $6 aerator is smart; replacing a $200 faucet because I stripped the threads is not.
Cleaning a faucet aerator takes ten minutes and costs nothing if you have vinegar and a toothbrush. The diagnostic test — unscrewing the aerator and timing how long it takes to fill a cup from the bare spout — tells you in 30 seconds whether cleaning will solve your water flow problem or whether you need to look elsewhere. For another low-risk plumbing fix that prevents expensive service calls, see How to Fix a Running Toilet in 3 Steps.