How to Replace a Sink Strainer

Step 1: Make sure the sink strainer is the part causing the leak

1. Dry the area around the sink drain, the underside of the sink, and the drain connections below it.
2. Run a small amount of water into the sink and watch where the first moisture appears.
3. Look for water seeping from the rim of the strainer at the sink opening or from the strainer body just below the sink, not only from a loose slip nut farther down the drain.
4. Check the strainer for rust, pitting, cracks, or a basket that no longer seats properly.

If it works: You confirmed the leak or damage is at the sink strainer itself, so replacement is the right repair.

If it doesn’t: If the leak is only at a slip nut, trap joint, or supply line, tighten or repair that connection instead of replacing the strainer.

Step 2: Clear the area and disconnect the drain below the strainer

1. Remove items from the cabinet so you have room to work.
2. Place a bucket or shallow pan under the trap area.
3. If the sink has a disposer or dishwasher connection, make sure you understand which drain parts support each section before loosening anything.
4. Loosen the slip nuts or other drain connection directly attached to the strainer tailpiece and lower that section out of the way.
5. Wipe up any water that drains out so the hardware is easier to grip.

Step 3: Remove the old sink strainer

1. From below the sink, loosen the large locknut that clamps the strainer to the sink.
2. Remove any friction ring, gasket, or backup washer under the sink as the assembly comes apart.
3. Push the old strainer body up and out from below, or pull it out from above if it is already loose.
4. Scrape all old putty, sealant, and debris from the sink opening and from the surrounding sink surface.
5. Wipe the area clean and dry so the new seal can seat evenly.

Step 4: Install the new sink strainer with a fresh seal

1. Check the new sink strainer parts against the old one so the connection style and depth make sense for your drain setup.
2. Apply a rope of plumber's putty under the new flange unless the new strainer instructions call for a different supplied seal.
3. Set the strainer into the sink opening from above and press it down evenly.
4. From below, install the gasket, friction ring, and locknut in the correct order for the new assembly.
5. Hold the strainer centered while tightening the locknut until the flange is snug and putty squeezes out evenly around the rim.
6. Wipe away the excess putty from the sink surface.

Step 5: Reconnect the drain and align everything without strain

1. Reconnect the tailpiece or drain section below the new strainer.
2. Thread the nuts by hand first so they do not cross-thread.
3. Tighten slip nuts firmly but do not overtighten plastic parts.
4. Make sure the trap and connected piping line up naturally and are not being forced sideways to meet the new strainer.
5. Wipe all joints dry so leak testing is easier to read.

If it doesn’t: If the pipes no longer line up, adjust the trap or tailpiece arrangement before tightening everything fully.

Step 6: Test the repair under real use

1. Run a slow stream of water and check around the strainer flange, the underside of the sink, and each reconnected joint.
2. Fill the sink partway, then release the water to send a larger volume through the drain.
3. Wipe each connection with a dry paper towel to catch small leaks that are hard to see.
4. If needed, snug the locknut or slip nuts a little more, then test again.
5. Check again after the sink has been used normally for a short time.

If it works: The sink drains normally and stays dry at the strainer and drain connections during both light flow and a full drain-down test.

If it doesn’t: If water still appears at the flange, remove and reseal the strainer. If the leak is lower down, replace the affected washer or reconnect that joint correctly.