How to fix a slow drain

Steps

Goal: Remove the cover, clear visible debris, and try the simplest fix first.

• Unscrew or pry up the drain cover with a flathead screwdriver. If the stopper is push-pull or lift-and-turn, twist it counterclockwise and lift it out.
• When the cover is off, look for hair or soap buildup at the opening. If you find one, pull it out with needle-nose pliers and check that water flow improves.
• Good: Water drains after removing debris. Proceed to Verification.
• Bad: Still slow—proceed to Try the plunger.

Try the plunger

Goal: Use a cup plunger to clear soft clogs (hair, soap, grease) near the opening.

• Use a cup plunger—not a flange plunger—for flat drains. Fill the sink or tub with enough water to cover the rubber cup.
• Press the plunger down to form a seal and pump firmly 10–15 times. When you lift the plunger, verify that water drains freely.
• If it still pools, repeat two more rounds before moving on.
• Good: Water drains freely. Proceed to Verification.
• Bad: No change—try Flush with hot water or Baking soda and vinegar.

Flush with hot water

Goal: Loosen grease and soap buildup before trying baking soda and vinegar.

• Use very hot tap water (from the tap at maximum heat). If you have metal pipes, you can use boiling water. Pour it slowly into the drain in two or three stages, pausing 5 seconds between pours.
• For PVC pipes, use very hot tap water only—do not use boiling to avoid softening the plastic.
• Good: Standing water swirls and drops; drain flows better. Proceed to Verification.
• Bad: No change—try Baking soda and vinegar or Drain snake.

Baking soda and vinegar

Goal: Break down grease and soap buildup with a safe, non-chemical treatment.

• Pour half a cup of baking soda directly into the drain opening. Follow with half a cup of white vinegar.
• When the mixture foams, cover the drain with a wet cloth to direct the pressure downward. Wait 15–20 minutes, then flush with hot water.
• For PVC pipes, use very hot tap water instead of boiling to avoid softening the plastic.
• Good: Water drains at normal speed; no pooling. Proceed to Verification.
• Bad: Still slow—try Drain snake or Clean the P-trap.

Drain snake

Goal: Reach deeper blockages that the plunger cannot clear.

• Feed a hand-crank drain snake into the opening until you feel resistance. Crank the handle clockwise to bore through or hook the clog.
• When the snake moves freely, pull it back slowly. If you find debris on the tip, you have reached the blockage. Run water and verify the drain flows at full speed.
• Good: Water drains at full speed. Proceed to Verification.
• Bad: Snake hits a hard stop that will not budge—that could be a pipe fitting, not a clog. See When to get help.

Clean the P-trap

Goal: Clear blockages in the P-trap (the U-shaped pipe under the sink) when the snake does not reach the clog.

• For tub or shower drains, the trap may be behind an access panel or under the floor; call a plumber if you cannot reach it.
• Place a bucket under the P-trap. Unscrew the slip nuts on both ends by hand or with channel-lock pliers.
• When the trap drops free, dump its contents into the bucket. Look through the trap and pipe stubs—you should see daylight or light from the other end.
• Reassemble finger-tight, then snug a quarter turn with pliers. Run water and verify the drain flows.
• Good: Water drains; no drips at the slip nuts. Proceed to Verification.
• Bad: Water still pools—the clog is deeper than the trap. See When to get help.

When to get help

Call a plumber if:

• The snake hits a hard stop that will not budge (could be a pipe fitting or main-line blockage).
• Water backs up from multiple fixtures (suggests main-line blockage).
• You smell sewage (possible main-line or vent issue).

A plumber has longer snakes and can scope the pipe to locate the problem.

Verification

• Run water at full volume for 60 seconds. Water should drain without pooling.
• Check for drips at the P-trap connections (under the sink) or at drain connections.
• Repeat the flow test after 24 hours to confirm the drain has not slowed again.