How to Fix a Leak in a Kitchen Sink Flange

Sink flanges connect and create a seal between the sink surface and the drain pipe or garbage disposal underneath. Over time the seal can break down due to a cracked gasket, dried-out plumber's putty or movement from the garbage disposal. If there is a small amount of water leaking down the side of the drainpipe from directly under the sink drain, a leaky flange is likely to blame. Left unfixed, the leak could grow, causing water damage.

Sink flange pictured at right

Step 1

Turn off the water. If you have a garbage disposal, turn off the main circuit breaker switch for the disposal before proceeding.

Step 2

Loosen the drainpipe with the adjustable wrench. If you see nuts and bolts connected to the underside of the sink, loosen the nuts instead, and gently push the bolts upward.

Step 3

The sink flange pictured here. Note that some flanges are just the outer rim you see here while the center piece comes out when you remove the flange.

Lift out the flange on the top side of the sink. The flange is the framing of the sink drain and is thin metal. Carefully inspect the rubber gasket underneath for cracks or tears. The gasket is rubber and generally black in color, and is exposed once you life off the flange. If the gasket is torn or cracked, remove it and replace it with a new gasket.

Step 4

Apply plumber's putty around the inner edge of the sink opening where the opening meets the gasket. Pop the flange back in place.

Step 5

Apply some plumber's putty in the small gap between the underside of the flange and the pipe or garbage disposal top where the nuts and bolts connect.

Step 6

Tighten the nuts, which squeezes the putty further between the sink and pipe. Do not overtighten.


  • Never try to replace the gasket or work on the flange with the water running or the disposal powered on.
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