Drain Repair

A household drain system removes waste water from sinks, tubs, showers, and even a wet basement, dumping it into the sewer or drainage system exiting your home. This Fix-It Guide on drain repair tells how a drain system works, what often goes wrong, how to identify a drain problem, and what parts and tools you will need to fix it. It then gives simple step-by-step instructions for how to clear a clogged sink or bathtub drain, how to adjust a bathroom sink stopper, how to stop leaks around a drain flange, how to service a bathtub drain assembly, how to replace a drain flange and other drain repairs.

How Does a Drain Work?

Drain System Repair

Components of a typical drain system.

A household drain system consists of the drain assembly at the sink, tub, shower, or floor and the pipes that conduct it out of the house. Most drains include a trap (a U-shaped pipe) below the fixture to trap sediment and to create a barrier that prevents drainage odors from traveling back up the pipe, through the drain, and into the room. Household drains also include a ventilation system to allow gases and odors to escape through a home’s roof.

What Can Go Wrong with a Drain?

By far the most common problem with a drainage system is clogs. Fortunately, most clogs occur in the trap. In fact, that’s the intent of the trap, to give household drains a place to collect sediment in a location that’s easily accessed and cleaned. Less frequently, sink stoppers can get out of adjustment and pipes under the sink or in a wall can leak.

Fix-It Tip

The most common cause of clogged drains in bathtubs and showers is hair and soap sludge. Periodically use a drain cleaning product to dissolve these impediments and send them down the drain where they belong. Make sure you carefully follow instructions on the product’s container.

How Can I Identify a Drain Problem?

Household drains will tell you when they have a problem doing their job. Solutions are relatively easy to apply. Ongoing maintenance will keep them from becoming damaging problems.

  • If a drain becomes clogged, first try to clear the drain with a plunger (see below).
  • If a sink stopper doesn’t stop water from draining or doesn’t open all the way, adjust the stopper (see below).
  • If the problem is at the main drain, use a plumbing auger or expansion nozzle to clear the line (see below).
  • If pipes under a sink leak, tighten connections or replace the drain flange (see below).


If the drain is completely stopped up, don’t use chemical drain cleaners as they can release noxious fumes and burn unprotected skin. You’ll be left with a sink or tub full of caustic chemicals. Also, never use chemical drain cleaners with a plunger as the pumping action can splash the chemicals on you.

What Do I Need for Drain Repair?

You’ll find replacement parts for household drains at your local hardware or plumbing supply store, along with tools to do the job right:

  • Plunger
  • Pipe wrench
  • Screwdrivers
  • Auger or wire coat hanger
  • Expansion nozzle
  • Garden hose
  • Adjustable pliers
  • Bucket and rags
  • Plumber’s putty
  • Vinegar
  • Bottle brush

What Are the Steps to Drain Repair?

Clear a clogged (not stopped) sink or bathtub drain with a plunger:

  1. If you have a dishwasher, pinch off the rubber dishwasher drain hose that leads to the garbage disposer using a clamp or locking pliers. If clearing a bathtub, remove the drain stopper and cover the overflow opening with a wet rag.
  2. Remove the sink basket or tub stopper and clean any debris from the drain opening.
  3. Fill the sink or tub with sufficient water to cover the plunger cup, usually about 2 inches. If you are working on a double sink, seal the other sink with a stopper so the plunger can create a vacuum.
  4. Set the plunger on the drain opening and repeatedly pump it up and down, then pull away sharply to dislodge debris. Repeat if necessary.
  5. Turn on warm or hot water to flush loosened debris from the drain.
  6. If the clog remains, use an auger (see below) or an expansion nozzle (see below) to clear the drain.

Clear a clogged drain using an auger:

  1. Remove the stopper or strainer. If unable to do so, disassemble the drain trap (see below) and feed the auger directly through the pipe. Make sure you have a pail and rags nearby in case of a water spill.
  2. Release the setscrew on the auger and begin feeding the cable into the open drain.
  3. Once the auger tip hits the clog, set the screw and crank the auger clockwise to break up the clog.
  4. Continue breaking up the clog and moving it down the drain line with the auger. Once there is no more resistance to forward motion of the auger, stop and carefully remove the auger.
  5. If the clog can’t be moved, continue twisting the auger to possibly snag and retract the clog.
  6. Once the clog is cleared, flush the drain with boiling water.

Clear a clogged drain using an expansion nozzle:

  1. Attach the expansion nozzle to a garden hose and attach the hose to a faucet.
  2. Seal off all nearby drains so you can build water pressure in the line with the expansion nozzle.
  3. Insert the nozzle as far into the open drain as possible.
  4. Turn the water slowly to full force, inflating the nozzle to seal the drain and to apply water pressure for 15 to 30 seconds to clear the clog.
  5. Once done, detach the hose from the faucet to let the nozzle deflate before removing it.

Clear a clogged drain by removing the trap:

  1. Place a pan or pail under the trap to catch water and debris.
  2. Loosen the slip nuts on each end of the trap with adjustable pliers.
  3. Remove the trap and pour out any water and debris. If the trap is blocked, use a straightened coat hanger to clear it.
  4. If there is no clog in the trap, the blockage may be in the wall pipes. Use an auger or the coat hanger to clear the drain line on each side of the trap. Reinstall or replace the trap.

Adjust a bathroom sink stopper:

  1. Remove the stopper from the drain. On some models, twist the stopper to free it from the pivot rod or unscrew the retaining nut on the back of the drainpipe and pull out the pivot rod.
  2. Clean the stopper and replace the O-ring, if used.
  3. Reinsert the stopper, reconnect the pivot rod, and tighten the retaining nut. To test, add water to the basin and watch to see if the stopper holds water; if it does not, continue with step 4.
  4. Adjust the metal spring clip, sliding it up or down the pivot rod as needed to seat the stopper.

Stop leaks around a drain flange:

  1. Remove the stopper and drainpipe, and disconnect the lift rod to remove the drainpipe from the sink.
  2. Apply plumbers’ putty or silicone caulk under the lip of the drain flange.
  3. Reinstall the parts and wipe away any excess putty or caulk around the flange.

Service a bathtub drain assembly:

  1. Remove the stopper and clean the drain.
  2. Remove the overflow plate screws and remove the lift assembly. Clean debris from the pipe.
  3. If necessary, purchase and install a replacement bathtub drain assembly following the manufacturer’s directions.

Replace a drain flange:

  1. Remove the pop-up stopper or strainer.
  2. Remove the overflow plate and lift assembly.
  3. Disconnect the lift rod and reinstall the overflow plate.
  4. Use pliers to unscrew the drain flange.
  5. Apply plumbers’ putty or silicone caulk under the lip of the drain flange.
  6. Screw the flange into the drain opening and thread the metal stopper into the cross piece.

Fix-It Tip

Most clogs can be avoided. Place strainer baskets in drain openings. Pour grease and coffee grounds into the trash instead of down the drain. Occasionally pour boiling water down each drain to keep it from getting clogged.