How To Unclog a Drain

By: Fix-It Club

There are a number of plumbing repairs that require immediate attention. Chief among these is a clogged drain. Everyone knows the inconvenience and mess that accompany a sluggish drain. Even so, many people wait until the drain stops completely before they take corrective action. Sometimes a clog can be cleared with a simple homemade remedy.

If you have a moderately clogged drain, try this homemade drain cleaner: Pour 1/2 cup of baking soda down the drain followed by 1/2 cup of vinegar. Be careful. The baking soda and vinegar interact with foaming and fumes, so replace the drain cover loosely. Let the concoction set for about three hours before running water.

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If you know the slow drain is from grease, try this treatment: Pour in 1/2 cup of salt and 1/2 cup of baking soda followed by a teakettle of boiling water. Allow to sit overnight.

You can keep your drains clog-free and odorless by using the following homemade noncorrosive drain cleaner weekly. Combine 1 cup baking soda, 1 cup table salt, and 1/4 cup cream of tartar. Stir ingredients together thoroughly and pour into a clean, covered jar. Pour 1/4 cup of mixture into drain, and immediately add 1 cup boiling water. Wait 10 seconds, then flush with cold water. Flushing weekly with a generous amount of boiling water also works well.

If the homemade drain cleaners don't work, try the helpful steps on the next page.

How To Clear a Clogged Drain

To unclog a sink drain, cover the plunger's rubber cup with water and plug the fixture's vent opening with wet rags.

Dealing with a clogged drain is just no fun. Fortunately, there are steps you can take before calling a plumber to try to clear that clog. 

Step 1: Cover overflow opening in basin or tub with wet cloth. Most kitchen sinks don't have an overflow vent, but if you're working on one of two side-by-side basins, plug the other basin's drain opening with wet cloths. In homes that have two bathrooms back to back in adjacent rooms, both may be connected to the same drain. In such cases you must block the other basin at both its drain and overflow vent. Shower facilities seldom have overflow vents; bathtubs do. Cover all of them with wet cloths for plunger to work properly.

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Step 2: Fill clogged basin with enough water to cover head of plunger. Coat lip of plunger with petroleum jelly (this helps create better seal). Slide plunger's cup over drain opening, then rapidly pump plunger up and down. You should feel water move in and out of drain. It is this back-and-forth water pressure that can eventually build up enough force to dislodge whatever is blocking drain. After about a dozen firm strikes, jerk plunger up quickly. Water should rush out. If it doesn't, try same procedure two or three more times before attempting another method.

If the clog is not in the fixture's trap, insert a drain-and-trap auger into the drain extension that goes into the wall, and work the auger into the drainpipe.

Step 3: If plunger doesn't remove clog, consider using chemical drain opener. For drain that's completely blocked, however, it's best not to use chemicals, as they contain caustic agents that can actually harm some fixtures. Instead, use drain-and-trap auger. To use it, remove popup stopper or strainer from clogged drain and insert auger wire into opening. As you feed flexible wire in, crank handle of device, loosening and then tightening thumbscrew on handle as you advance wire. If wire encounters something, move it back and forth while you turn auger handle. Then continue to turn handle while slowly withdrawing auger.

A clog near the tub's drain can be attacked from several places -- the overflow opening (as shown), the tub drain opening, or the drum trap. Start working at the tub drain. If you can't remove the obstruction there, move onto the overflow and then the drum trap.

Step 4: If auger doesn't clear drain, remove clean-out plug from under sink, catching water from trap in bucket. You can use wire coat hanger with hook shape in one end to try to reach clog. If this fails, insert wire of drain-and-trap auger through clean out. Work wire toward basin and drainpipe to remove blockage.

Step 5: If trap does not have clean out, remove trap. (The section How to Replace a Drain Trap provides complete instructions on how to remove and replace a drain trap.) With trap removed, clean it out with wire coat hanger and then with stiff brush and hot soapy water; replace trap. If clog wasn't in trap, insert drain-and-trap auger into drain extension that goes into wall and continue working auger down into drainpipe itself. You should be able to reach blockage, unless it's in section of main drain.

Step 6: If bathtub drain is clogged and plunger doesn't clear it, use drain-and-trap auger first through tub drain opening. If this doesn't work, remove overflow plate and insert auger directly into overflow pipe and down into drainpipe.

Unclogging floor drains and main drainpipes is another job altogether. Find suggestions for tackling these plumbing issues in the next section.

How To Clear Floor Drains and Main Drainpipe Blockages

A clog in the main drain can be reached from the main clean out, which is the Y-shape fitting near the bottom of your home's soil stack or where the drain leaves the building.

For clogged floor drains, such as those in basements and showers, a garden hose can be effective in unclogging drains, especially if the clog is not close to the opening. Attach the hose to a faucet, feed the hose into the drain as far as it will go, and jam rags around the hose at the opening. Then turn the water on full force for a few moments.

If you suspect a clog is in the main drainpipe, locate the main clean out. This is a Y-shape fitting near the bottom of your home's soil stack or where the drain leaves the building. Set a large pail or container under the clean out, and spread plenty of papers and rags around the site to soak up the backed-up water.

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Using a pipe wrench, slowly unscrew the clean-out plug counterclockwise, trying to control the flow of water that will seep from the clean out. Once the flow has stopped and you've cleaned up the flooded site, insert the auger to remove the debris.

If you still haven't located the blockage, another place you can try is the house trap. This is a U-shape fitting installed underground. You can locate it by finding two adjacent clean-out plugs in the floor, if the main drain runs under the floor. Again, place papers and rags around the site before opening the clean out nearest to the sewer outside.

If the clog is in the house trap or between the trap and the main clean out, you should be able to remove it. But if the water starts to flow out of the trap as you unscrew it, check quickly beyond the house trap with an auger. If you can remove the clog rapidly, do so. Otherwise, replace the trap plug and call in a professional to do the job.

The house trap is a U-shape fitting installed underground. You can locate it by finding two adjacent clean-out plugs in the basement floor. A blockage between the trap and the main clean out can be reached by removing the plug closest to the main clean out.

There is one type of drain clog that will not respond satisfactorily to a plunger or an auger. This is when the main drain outside the building or a floor drain in the basement gets stopped up from tree roots that have grown in at the joints. The most effective solution in this case is a power auger or an electric rooter, which is inserted into the pipe and cuts away roots from the pipe walls as it moves along. You can rent a power auger at a home improvement or tool rental store. Feed the auger cable into the cleanout opening closest to the blockage. When the device's cutting head encounters roots, you should be able to feel the cable strain. Keep feeding the cable slowly until you feel a breakthrough, then go over the area once again.

Remove the cable slowly, and run water from a garden hose through the pipe to wash away the root cuttings. Before you return the power auger to the rental firm, replace the clean-out plug, and flush a toilet several times. When you're sure the drain is clear of tree roots, clean the cable.

The drain trap is an integral part of your home's drainage system. We'll show you how to replace a drain trap in the following section.

How To Replace a Drain Trap

To remove the drain trap, unscrew the slip nuts with a wrench and slide them out of the way.

Directly beneath the drain outlet of every kitchen sink and every bathroom lavatory is a trap. This element is vital not only to the proper functioning of the drainage system but also to your health and safety. Each drain trap contains and maintains a plug of water within its curved section that seals against the entrance of harmful sewer gases. If the drap trap leaks, this water barrier may disappear and create a hazardous situation.

All drain traps must be kept in proper working order. Restrictions and clogging are immediately noticeable because the drainage flow is slowed or stopped. Clearing the blockage takes care of the problem. Leakage or seepage can often go undetected for a while, so check your traps from time to time and make quick repairs if anything seems wrong.

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Drain trap assemblies have several parts. The short piece of pipe that extends downward from the drain outlet flange in the sink or lavatory is called the tailpiece. The curved section of pipe connected to the tailpiece is the trap itself. The trap may be either one piece or two coupled sections. The piece of pipe extending from the end of the trap to the drainpipe outlet in the wall or floor is the drain extension. All of these pieces may be made of rather thin metal that is subject to corrosion, seal failure, and mechanical damage. Damage can also result from reaming with a plumbers' auger. Whatever the reason for failure, a malfunctioning trap should be repaired immediately.

Sometimes the problem is simply that the slip nuts holding the drain trap assembly to the drain and the drainpipe have loosened. Tightening them may solve the problem. But if the metal has corroded through, if the slip-nut threads are damaged, or if other damage has occurred, the only solution is replacement.

Drain trap assemblies and parts to fit just about any possible installation requirement are readily available at most hardware and all plumbing supply stores. Chrome-plated thinwall brass traps are popular, especially where appearance is important. Polypropylene (PP) plastic traps, notable for their ruggedness and longevity, will outperform all other types. ABS plastic traps are also in use, but they become deformed and eventually fail when forced to handle frequent passage of boiling water and caustic household chemicals. In addition, they may not be allowed by your local plumbing code. Ask the plumbing clerk at your local building materials retailer for recommendations.

Whatever the material, there are typically two trap diameters: 11/2-inch traps for kitchen sinks and 11/4-inch traps for lavatories. Take the old trap with you when you buy the new one; if possible, also take the old tailpiece and drain extension. In most cases, trap replacement is simple. Here's how:

Step 1: If trap is equipped with cleanout plug on bottom of curved section, remove plug with wrench and let water in trap drain into bucket. Otherwise, unscrew slip nuts and slide them out of the way.

Step 2: If trap is a swivel type, curved trap section(s) will come free. However, keep trap upright as you remove it, and pour water out after part is free. If trap is fixed and does not swivel, remove tailpiece slip nut at drain flange and slip nut at top of trap. Shove tailpiece down into trap itself, then twist trap clockwise until you can drain water in trap. Pull tailpiece free, and unscrew trap from drain extension or drainpipe.

Step 3: Buy drain trap of proper diameter, new tailpiece, drain extension, or other fittings, as necessary. A swivel trap is the easiest to work with because it can be easily adjusted for angled or misaligned drainpipe/fixture installations. A clean-out plug on a trap is handy so trap can be cleaned out without removing it.

Step 4: Replace parts in appropriate order, making sure you have slip nuts and compression seals, or large washers, lined up on the proper pipe sections. Couple parts together loosely with slip nuts, make final adjustments for correct pipe alignment, and tighten nuts snugly but not too tight. Plumbers' joint tape or compound is not usually necessary, but you can use either.

Step 5: Run water into new trap immediately, both to check for leaks and to fill trap with water to provide that all-important barrier against sewer gases.

As you can see from the tips in this article, a clogged drain does not necessarily mean a huge plumbing bill. Follow the steps detailed on these pages and you may just unclog that drain all on your own.