Domakihub Replace a Kitchen Sink Strainer Without Leaks
A step-by-step guide to swapping out a seized strainer and sealing the new one so it stays watertight for years.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
A leaking or corroded sink strainer is one of the most common — and most overlooked — causes of under-sink water damage in Greek homes, holiday apartments, and hotel kitchens. The video above walks through the full process clearly, and the steps below give you the detail you need to do the job right the first time. Whether you are maintaining a villa in Crete or a city apartment in Athens, this repair takes under an hour and requires no specialist skills.
Why Strainers Fail — and Why It Matters
Sink strainers sit in a constant cycle of hot water, soap residue, and mechanical stress from drain plugs being pushed in and pulled out. Over time the putty or silicone seal beneath the basket flange hardens, shrinks, and cracks, allowing water to seep through the sink hole and drip onto the cabinet below. In holiday rentals and hotel properties, where the sink may be used intensively by many guests, this deterioration happens faster than in a primary residence.
A weeping strainer does not always announce itself with a dramatic drip. More often it leaves faint mineral stains on the cabinet floor or a faint musty smell from damp wood. Catching it early — and replacing the strainer body entirely rather than just re-caulking — is the correct fix.
Tools and Parts to Gather Before You Start
You will need a replacement strainer basket that matches your sink's drain opening diameter (the standard is 90 mm / 3.5 inches in most European kitchens), plumber's putty or silicone sealant suited to your sink material, a pair of channel-lock pliers, a strainer wrench or a pair of needle-nose pliers, and a flat-blade screwdriver. A bucket and a few old towels will keep the cabinet dry while you work.
If the existing strainer is badly corroded, also pick up a penetrating oil spray such as WD-40 and allow it to soak for 15 minutes before attempting removal. This alone saves most of the struggle on old Greek stone or ceramic sinks where fittings have not moved in a decade.
How to Replace a Kitchen Sink Strainer: 5 Steps
- 1
Clear the cabinet and disconnect the drain
Empty the cabinet beneath the sink completely. Place a bucket under the P-trap. Loosen the slip-nut where the drain tailpiece meets the P-trap by hand or with channel-lock pliers, then slide the trap down and set it aside. This gives you clear access to the lock nut that holds the strainer body in place from below.
- 2
Remove the old strainer body
Have a helper hold the strainer basket from above — pressing down firmly with a screwdriver through the crossbars — while you use a strainer wrench or needle-nose pliers to turn the large plastic or metal lock nut counter-clockwise from below. On a seized fitting, apply penetrating oil first and wait 15 minutes. Once the nut is off, lift the old strainer body up through the hole from above. Scrape away every trace of old putty or silicone from both the sink surface and the underside of the hole using a plastic scraper; residue left behind will prevent a good seal on the new fitting.
- 3
Prepare and seat the new strainer
Roll a rope of plumber's putty roughly 1 cm in diameter and press it around the underside rim of the new strainer flange. If your sink is stainless steel or the manufacturer recommends it, use clear silicone sealant instead. Lower the new strainer body into the drain hole from above, pressing it down firmly and evenly so the putty spreads to fill the gap. Do not twist it at this stage — just press straight down.
- 4
Secure the lock nut from below
Working beneath the sink, slide the rubber gasket, the friction ring, and the lock nut onto the tailpiece of the strainer in that order, then thread the lock nut clockwise by hand until snug. Use the strainer wrench to tighten it a further quarter to half turn. As you tighten, excess putty will squeeze out from under the flange above — this is correct. Once the nut is firm, go back up top and use a screwdriver or your fingers to peel away the squeeze-out cleanly. Do not over-tighten: cracking a ceramic sink flange is an expensive mistake.
- 5
Reconnect the drain and test for leaks
Reattach the P-trap tailpiece and tighten the slip-nut hand-tight plus a quarter turn — no tools needed on plastic fittings. Fill the sink with water, then pull the plug and observe the underside while the water drains. Run your finger around the flange edge from below; it should be completely dry. Let the sink drain fully, then check again after two minutes. If any moisture appears at the lock nut, tighten it a fraction more. Silicone-sealed installations should be left to cure for 24 hours before the sink is used heavily.
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FAQ
- Can I use silicone sealant instead of plumber's putty?
- Yes, and for composite, granite, or certain coated sinks silicone is actually the better choice because plumber's putty can stain those surfaces. Use a clear or white kitchen-grade silicone rated for constant water contact. The trade-off is curing time — you need to leave the sink unused for at least 24 hours, compared to an instant seal with putty.
- My lock nut is completely seized and will not turn. What should I do?
- Soak the nut with penetrating oil and wait at least 15 minutes. If it still will not budge, use a hacksaw or oscillating multi-tool to carefully cut through the plastic nut from below — the blades will not reach the sink surface if you angle them correctly. Alternatively, a licensed plumber with an impact driver can free almost any seized fitting in seconds. Forcing it with excessive leverage risks cracking the sink.
- How often should a kitchen sink strainer be replaced?
- A good-quality stainless or brass strainer body should last 10 to 15 years. In a holiday rental or hotel kitchen with heavy continuous use, inspect the seal annually and replace the entire unit if the basket shows significant corrosion, if the seal has visibly cracked, or if you notice any moisture in the cabinet below. Replacing the strainer proactively during a general kitchen renovation is also good practice.