How to Snake a Drain

snake a bathtub drain

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If you've tried unsuccessfully to clear a clogged drain with a plunger, do what a plumber would do and use a drain snake. Drain snakes come in a variety of types and sizes. Most sink clogs can be cleared with a standard 25- or 50-foot drain snake, while toilet clogs are a cinch if you have a toilet auger. For very long drain runs in the house, a mini-rooter might be necessary, and for 4-inch sewer drains you'll need a full-size sewer auger. Regardless of the type, all drain snakes use cables with special ends for snagging or cutting through the source of the clog.  

Toilets

A toilet stoppage is probably the most common of all household clogs. If the stoppage is in the toilet itself or in the drain close to the toilet, you should clear the clog with a toilet auger. It is not safe to use any other type of snake in a toilet. A toilet auger can be pushed all the way up into the throat of the toilet before going through the toilet trap, so it will not scrape the insides of the toilet bowl. Also, the cable of the toilet auger is stiff enough so that it won't loop back on itself when it hits the stoppage.

Tub Drains

Tubs and tub/shower combos are snaked through the overflow drain of the tub. To clear a clogged tub, first, check to make sure that there is no collection of hair stuck in the cross-hairs of the tub drain. You may need to remove the tub stopper to access the cross-hairs. If the cross-hairs are clean, the tub stoppage is likely to be farther down the drain, and you can snake the tub drain through the overflow. Use a standard drain snake with a 1/4- or 5/16-inch cable. Heavier cables may be hard to get through the bends in the trap under the tub and could damage the drain pipe.

Shower Drains

A drain for a standard shower (not a tub/shower combo), usually has a 2-inch drain going straight down into a trap below the shower base. While this is bigger than a tub drain, it's still a good idea to use a standard snake with a 1/4- or 5/16-inch cable, so the cable goes through easily. Most 1/4-inch drain snakes come with a 25-foot cable, which is plenty long to clear a shower stoppage. Shower clogs are usually caused by a buildup of hair and soap scum and are easy to clear.

Washing Machine Drains

Many washing machine drain lines have a clean-out near the washing machine that can be used to run the snake directly into the drain pipe. If the stoppage is close to the machine, such as in the trap or standpipe, you can use a small standard snake and run it down the standpipe and through the trap. If the stoppage is farther down the line, you should feed the snake through the clean-out, and you may need a mini-rooter with a 50- or 75-foot cable.

Kitchen Drains

Kitchen drains may include a clean-out on an outside wall (in warm climates only) or inside the sink base cabinet or in the basement or crawlspace area underneath the kitchen. If so, it's best to snake the drain from the clean-out. A standard 25- or 50-foot drain snake should do the trick. If the stoppage occurred before the clean-out, you may have to disconnect the P-trap under the sink and feed the snake directly into the drain pipe.

Bathroom Sink Drains

Many lavatory drain stoppages are due to hair clogs around the pop-up stopper assembly. You may be able to reach the clog with needlenose pliers or a metal coat hanger with a hook on the end. Failing that, disconnect the P-trap and check it for clogs. If you find nothing in the trap or pop-up area, then the stoppage is farther down the line and can be snaked from under the sink. A standard 25-foot drain snake takes care of most bathroom sink stoppages.

Main Drains

A main drain, or main sewer drain, is typically 3 or 4 inches in diameter and requires a sewer auger to clear most stoppages. Using a standard snake or, in some cases, a mini-rooter, can lead to problems, such as the cable doubling back on itself or tying itself into knots inside the drain pipe. This happens because the cable isn't stiff enough and the extra room in the large-diameter pipe allows the cable to wind up into knots.

Full-size sewer augers have 5/8- or 3/4-inch cables that are very rigid so they don't twist or get stuck easily. Sewer augers are commonly available at rental centers for half-day (4-hour) and all-day rental. They are great for pushing or cutting through most stoppages, including those caused by annoying tree roots. Make sure to get a quick lesson on operating the machine from the rental company; they can be dangerous if not used properly.

Tools and Supplies You Will Need

  • Wrench or tongue-and-groove pliers
  • Rags
  • Rubber or latex gloves
  • Drain snake

Instructions

Open the Drain

Gain access to the drain line by removing the appropriate part, using a large adjustable wrench, a pipe wrench, or tongue-and-groove pliers, as applicable. Remove the cleanout plug from the drain line, if available. Otherwise, for a sink drain, remove the drain stopper or the P-trap; for a tub drain, remove the overflow assembly; for a washing machine drain, remove the washer drain hose from the drain standpipe.

Prepare the Snake

Put on rubber gloves. Loosen the setscrew on the drain snake so you can freely pull out the cable.

Begin Snaking

Insert the snake into the drain, sliding in the cable until it meets resistance; this usually means it has hit a bend in the pipe but also could be the clog itself. Tighten the setscrew to clamp down on the cable; you don't need a lot of pressure, just enough to keep it from turning. Crank the snake handle clockwise while applying moderate pressure on the cable to work it into the drain. Stop when you can feel the cable move past the bend.

Continue Snaking

Loosen the setscrew, then feed the cable by hand until it meets resistance again. If, at any point, you can't feed the cable by hand, just let out about one foot of cable, tighten the setscrew, and crank the cable while pushing it into the drain. Continue snaking, using the same process, until you feel the clog or you've likely reached beyond the clog.

Retract the Cable

Loosen the setscrew and manually pull the cable back into the snake housing; it will wind itself inside the housing. If desired, run the cable through a rag held in one hand as you retract it, to keep the housing relatively clean. If the cable gets stuck inside the drain, tighten the setscrew and turn the handle counterclockwise while pulling backward on the cable; this should free the end of the cable so you can continue retracting it manually. When the cable is all the way out, remove any debris from its end.

Snake Again

Snake the drain again at least once, using the same techniques, to make sure the clog is cleared out. Even if you break through the clog on the first pass, you may have made just a small hole through it, especially if it's food or soap. Snaking two or three times helps to clear the drain completely.

Flush the Drain

Reinstall the cleanout plug, drain overflow, or P-trap, then flush the drain with a full flow of water for a few minutes. For a washing machine, you can run a small rinse and drain cycle, but watch the drain carefully to be sure the water is draining.