Leaking sink strainer. Every time I ran the faucet, water pooled under the cabinet and soaked the particle board shelf. The plumber quoted me $180 just to come look at it. I said no, drove to Home Depot, bought a $12 Danco replacement kit, and did the whole job in under 45 minutes. Here’s exactly how to do it — no plumbing experience needed.
TL;DR: Turn off the water, remove the old strainer with slip-joint pliers and a locknut wrench, scrape the old putty, press in the new strainer with fresh plumber’s putty, secure the locknut from below, reconnect the drain pipe, test. Total cost: $10-25 for parts. Time: 30-50 minutes.
What Tools and Materials Do You Actually Need?
You need fewer things than most guides claim. Here’s what I used:
- Plumber’s putty (a $4 tub covers 5 jobs — use DAP or Oatey brand, both work fine)
- Slip-joint pliers (a basic pair, nothing fancy)
- Adjustable wrench or channel-lock pliers
- Flathead screwdriver
- Plastic putty knife or an old credit card for scraping
- New strainer kit (Danco, Keeney — most standard kitchen drains are 3.5 inches)
- Old towel or a bucket for residual water
A rotary tool is optional. I never used one. Skip the power tools entirely for this job.
How Do I Know If the Strainer Needs Replacing?
Water under the cabinet after you run the sink is the clearest sign. A slow drain can just be a clog, but if you see water at the joint where the strainer meets the sink — that’s the seal. Rust streaks around the drain opening, a strainer basket that wobbles, or a locknut you can’t tighten any further all point to replacement rather than re-sealing.
I tried re-caulking mine once. Lasted three weeks. Just replace the whole unit.
How to Remove the Old Kitchen Sink Basket Strainer
Step 1: Clear out under the cabinet and put down a towel. There’s always a splash of standing water in the trap that goes somewhere when you disconnect the pipe.
Step 2: Disconnect the drain pipe from the strainer tailpiece. You’ll see a slip-nut (usually white PVC) connecting the P-trap to the bottom of the strainer body. Hand-loosen it, then use slip-joint pliers if it’s stuck. The pipe will drop an inch — that’s normal, let it hang.
Step 3: Stop the strainer from spinning. From above, press a pair of needle-nose pliers into the crossbars of the strainer basket. This holds it steady while you work from below.
Step 4: Loosen the locknut. The large plastic or metal nut below the sink is what holds the strainer in. Turn counterclockwise. Use channel-lock pliers or a large adjustable wrench. If it’s been there 10 years, expect resistance — it’ll budge. Mine took real effort on the first quarter turn, then came off by hand.
Step 5: Pull the strainer up from the top. Once the locknut is off and the rubber washer and snap ring are removed, push the strainer body up from below with a finger while pulling from the top. If it’s stuck in dried putty, twist and rock it — don’t yank straight up or you’ll chip the sink finish.
Step 6: Clean the sink opening. Scrape off every trace of old putty with your plastic knife. Go slow around stainless — a metal scraper leaves scratches. A rag with rubbing alcohol gets the residue off cleanly.
How to Install the New Basket Strainer
Step 1: Roll the plumber’s putty. Take a rope of putty about the diameter of a pencil and long enough to ring the drain opening — roughly 12 inches. Roll it between your palms until soft and pliable. Press it evenly around the lip of the sink drain hole.
Step 2: Seat the new strainer. Press the strainer firmly into the putty from above. Push down hard and twist slightly to squeeze the putty into the gap. Excess will ooze out around the edges — good. That’s the seal forming. Wipe the excess with a cloth or the putty knife.
Step 3: Install the hardware from below, in order. Slide the rubber gasket up against the sink underside first, then the paper washer, then the locknut. The gasket is the watertight seal; the locknut clamps everything in place. Thread the locknut up by hand until snug.
Step 4: Tighten the locknut while holding the strainer still. Same move as removal — pliers in the basket from above to stop it spinning, wrench on the locknut from below. Tighten until firm. Don’t overtighten or you’ll crack a plastic locknut.
Step 5: Reconnect the drain pipe. Slide the slip-nut back onto the strainer tailpiece. Hand-tighten, then a quarter-turn with pliers. No thread tape needed on plastic slip-joints.
How to Test for Leaks — Do This Before Closing the Cabinet
Plug the sink and fill it about halfway. Unplug it all at once — full pressure on the new joint. Dry the area under the sink completely first so you can see any drip. I run a strip of toilet paper along the joint at the strainer and along the drain pipe connection. Wet paper catches leaks the eye misses.
Drip at the strainer: the locknut needs another quarter turn. Drip at the pipe connection: tighten the slip-nut. Seepage from above around the sink opening: pull the strainer and add more putty — happens if the surface wasn’t fully clean.
What Surprised Me About This Job
The hardest part wasn’t the plumbing — it was breaking loose a locknut that had been on since 2008. Channel-lock pliers, a firm grip, patience. Also: some strainer kits come with a rubber gasket instead of putty instructions. The rubber gasket works fine for most sinks but not on rough or textured surfaces. On those, putty is more forgiving.
The other thing: plumber’s putty stains some composite and acrylic sinks. If your sink isn’t stainless, check the manufacturer’s recommendation. Oatey makes a “stain-free” putty that works on all surfaces.
Common Mistakes to Avoid
- Using silicone caulk instead of plumber’s putty. Caulk bonds permanently and makes future removal a nightmare. Putty stays soft and re-seals properly.
- Forgetting to check the drain pipe connection. Half the “leaking strainer” problems are actually loose P-trap nuts. Check both while you’re under there.
- Overtightening a plastic locknut. Firm is enough. You’re not building an engine.
- Skipping the leak test. Spend two minutes doing this before putting everything back. A second repair call costs another hour.
For related plumbing DIY, the guide to unclogging a shower drain covers similar under-sink work with the same basic tools.
If you run into a larger issue once you’re under there, 10 common plumbing issues walks through what’s DIY-safe and what needs a licensed plumber.
When Should You Call a Plumber Instead?
Call a professional if the drain pipe has corrosion damage, if the sink has cracks around the drain opening, or if the P-trap connects to a cast iron stack. A bad connection to cast iron inside a wall can cause long-term hidden damage. If everything under your sink is PVC or ABS plastic, you’re fine doing this yourself.
FAQ: Replacing a Kitchen Sink Basket Strainer
How long does it take to replace a kitchen sink basket strainer?
For a first-timer, budget 45-60 minutes including cleanup. Once you’ve done it once, 30 minutes is realistic. There are maybe eight steps, none of which requires special skill — just patience with the locknut.
Do I need to turn off the water supply to replace the strainer?
The strainer is in the drain, not the supply. You don’t technically need to turn off supply valves, but keep the faucet off while working. The bigger concern is draining the P-trap before disconnecting the pipe — tilt the trap into a bucket or towel.
What size strainer do I need?
Nearly all standard kitchen sinks in North America use a 3.5-inch drain opening. Buy a kit labeled “fits standard 3.5-inch drain” and it will fit. Some older farmhouse or non-standard sinks differ — measure the opening diameter if unsure.
Can I use silicone instead of plumber’s putty?
Only if the strainer kit specifically calls for it. Some kits with rubber gaskets do. Silicone creates a permanent bond and makes future removal messy. Plumber’s putty forms a flexible, watertight seal that stays workable for years.
Why is my new strainer still leaking after installation?
Most post-install leaks are one of three things: the locknut needs another half-turn, the putty wasn’t pressed in evenly (especially if the sink surface wasn’t clean and dry first), or the slip-nut on the drain pipe is loose. Work through each in order before assuming the strainer is faulty.
Updated June 2026 | By john
Thank you for reading!
