A blocked tap aerator is one of the most common — and easiest — plumbing fixes a homeowner can tackle themselves. The aerator is the small mesh screen screwed onto the end of your tap spout, and over time it collects mineral deposits, grit, and debris that restrict water flow. In most cases you can have it cleaned and refitted in under 30 minutes with basic household tools.
What Is a Tap Aerator and Why Does It Block?
An aerator mixes air into the water stream, giving you a smooth, splash-free flow while reducing water use — a handy feature for meeting the water-efficiency goals encouraged by Energywise. The fine mesh screen inside the aerator is very effective at trapping sediment, and in areas with hard water (common in parts of Canterbury, Hawke's Bay, and Waikato), limescale build-up can block it surprisingly quickly. Signs of a blocked aerator include:
- Reduced water pressure from one tap only
- Uneven or spluttering water stream
- Water spraying sideways from the spout
Tools and Materials You'll Need
- Adjustable spanner or slip-joint pliers
- Soft cloth or masking tape (to protect chrome finishes)
- Small bowl or container
- Old toothbrush
- White vinegar (distilled)
- Toothpick or pin (for stubborn debris)
- Replacement washer or O-ring (optional, in case the old one is worn)
You can pick up replacement aerators, O-rings, and white vinegar at Bunnings or Mitre 10. Take the old aerator with you so you can match the thread size.
Step-by-Step: Removing the Aerator
- Turn off the tap fully. You do not need to turn off the water supply at the toby (main shutoff) for this job.
- Place a cloth in the sink to catch any small parts that may fall.
- Wrap the spout with a soft cloth or a few layers of masking tape to protect the chrome finish.
- Unscrew the aerator by hand — turn anti-clockwise (lefty-loosey). Most aerators are hand-tight. If it won't budge, use an adjustable spanner over the cloth for extra grip. Avoid excessive force, as older fittings can be brittle.
- Note the order of parts as you disassemble. A typical aerator has a housing, one or two mesh screens, a flow restrictor disc, and a rubber washer. Lay them out in order on the bench.
Cleaning the Aerator
Soaking in White Vinegar
Place all the components in a small bowl and cover with undiluted white vinegar. Leave to soak for at least 30 minutes — or up to a few hours for heavy limescale build-up. The mild acid in vinegar dissolves mineral deposits without damaging the parts.
Scrubbing
After soaking, use an old toothbrush to gently scrub each mesh screen and the housing. A toothpick or pin can clear individual holes in the mesh. Rinse all parts thoroughly under running water.
Inspect the Washer
Check the rubber washer or O-ring for cracks or flattening. A worn washer is a common cause of drips once the aerator is refitted — replace it if in doubt. These cost very little at any hardware store.
Refitting the Aerator
- Reassemble the parts in the correct order (mesh screens, flow restrictor, then washer).
- Screw the aerator back onto the spout clockwise by hand until snug.
- Give it a gentle quarter-turn with the spanner — do not overtighten, as this can crack the housing or damage the thread.
- Turn the tap on slowly and check for leaks around the aerator. If it drips at the joint, tighten slightly or check the washer is seated correctly.
How Often Should You Clean Your Aerator?
As a general guide, cleaning every 6–12 months is sufficient for most NZ households. If you're on tank water or in a high-sediment area, you may need to clean more frequently. Rental properties covered by the Healthy Homes Standards must have functional hot and cold water supply, so landlords should keep aerators in good working order.
When to Call a Professional
Cleaning an aerator is not restricted plumbing work under the Plumbers, Gasfitters and Drainlayers Board (PGDB) rules, so homeowners can do this themselves. However, call a licensed plumber if:
- The aerator thread is damaged or the spout is cracked
- Low pressure persists after cleaning (could indicate a deeper supply issue)
- You notice corrosion or leaks at the tap body itself
- You want to replace the entire tap — tap replacement involving supply pipework is restricted work and must be carried out by a licensed plumber
For peace of mind or if you're unsure, you can find a qualified local plumber on tradedirectory.co.nz.
Safety note: Always confirm the tap is fully off before removing the aerator. If you accidentally drop small parts down the drain, turn off the water supply at the toby before attempting retrieval.
Master Plumbers
