How to snake a bathtub or shower drain

01 /Where do tub and shower clogs usually sit?

Tub and shower clogs usually sit in the first 30 cm below the drain, on the stopper, the crossbars of the drain body or the strainer, and in the trap just beneath. Hair combines with soap film and conditioner into a mat that thickens every time water runs through it. Sand from children's play, pet hair from bathing a dog, and grit from outdoor gear speed it up.

Before you open anything, run the tub or shower for ten seconds and watch the toilet and the bathroom sink. If either gurgles or the water level in the toilet bowl moves, the problem is downstream of all three, and the Clog Locator will help you place it.

02 /What kind of tub stopper do you have?

The stopper type decides how you get at the hair, and whether the overflow opening holds a linkage you have to lift out. Designs vary by maker, so if yours does not come apart as described, stop before forcing anything and look for the model instructions.

• Toe-touch (foot-actuated): the cap unscrews counter-clockwise when the stopper is in the open position, and the post beneath it unscrews with a screwdriver or by hand. Hair collects around the post.
• Lift-and-turn: a small knob on top; hold the body and unscrew the knob, then unscrew the stopper body, or remove a set screw under the knob on some models.
• Push-pull: similar to lift-and-turn; the knob unscrews and the body comes out.
• Trip lever with plunger: there is no stopper in the drain, only crossbars. The lever on the overflow plate lowers a brass plunger inside the overflow tube. Remove the two overflow plate screws and lift the whole linkage out; hair often hangs off the plunger.
• Trip lever pop-up: a rocker arm runs from the overflow linkage through the drain. Pull the stopper and its rocker arm straight up out of the drain, then remove the overflow plate and linkage.

03 /How do you snake a bathtub through the overflow?

Snake a bathtub through the overflow because the drain opening has crossbars that stop the cable and a sharp elbow, called the drain shoe, directly underneath. The overflow tube drops vertically into a tee on the same pipe, which gives the cable a straighter line into the trap below.

1. Protect the tub

   Lay a folded towel in the tub under the overflow so the cable and drum never touch the finish. Enamel chips, and acrylic or fibreglass scratches.

2. Remove the overflow plate

   Unscrew the two screws, pull the plate away and lift out any linkage attached to it. Note how it came out so it goes back the same way.

3. Feed cable down the overflow

   Push 1/4-inch hollow-core cable down the overflow opening by hand. It drops about 30 to 40 cm to the tee, then turns toward the trap.

4. Rotate at the first stop

   Lock the drum with a hand's width of cable exposed and crank clockwise with gentle pressure. The trap is usually the first real resistance.

5. Work through in short bites

   Advance a few centimetres, pull back, advance again. Hair clogs often feel spongy and then grab the head.

6. Retrieve while cranking clockwise

   Keep turning forward as you pull the cable back so the hair comes out on the head rather than staying in the trap.

7. Refit the linkage and test with volume

   Replace the linkage and overflow plate, fill the tub with 10 to 15 cm of water, and release it. A tub that empties in about the time it took to fill a few centimetres is clear.

If the cable passes the trap and runs another metre or two before meeting resistance, the clog is in the trap arm or the branch. You can keep going with 25 feet of 1/4-inch cable, but if it starts to coil or twist, the pipe is probably larger than the cable suits; see the auger cable size chart.

04 /How do you snake a shower drain?

Snake a shower drain by removing the strainer and feeding the cable straight down, because in most showers the trap sits directly below the drain opening. Canadian showers commonly drain through 2-inch pipe, some older ones 1-1/2 inch, so 1/4-inch cable handles the trap and 5/16 or 3/8-inch cable suits a clog further along.

1. Remove the strainer

   Most unscrew with one or two screws; some snap out with a flat blade at the edge; some tiled-shower strainers thread into the drain body and turn out by hand or with pliers on a crossbar.

2. Pull the hair you can see

   A barbed strip or bent-tip grabber reaches the first 20 to 30 cm, which is where most shower hair sits.

3. Feed cable down

   Push the cable in without rotation until it meets the trap bend, usually within the first half-metre.

4. Crank through the trap

   Rotate clockwise with light pressure; the trap bend passes more easily when the cable is turning.

5. Retrieve and flush

   Pull back while cranking forward, then run the shower hot for a few minutes and watch for pooling.

Linear shower drains have a long grate over a channel; lift the grate, clean the channel and its hair catcher, and snake the outlet at one end. Do not pry at the clamping ring or flange of a tiled shower drain. That ring holds the waterproof membrane, and disturbing it can create a leak under the tile that shows up later as a ceiling stain below.

05 /What if the house has an old drum trap?

Some older houses have a drum trap instead of a P-trap on the bathtub: a short metal canister, sometimes set in the floor near the tub with a screw-on lid flush with the floor or under an access panel. Hair and sludge settle in the canister, and a cable fed from the tub often cannot find its way through the inlet and outlet inside it.

If you find one, the drum trap lid is the access point. Old brass and lead lids seize and the canister itself can be fragile, so turn the lid gently with a proper wrench and stop if it will not move. Modern practice has moved to P-traps, and replacing a drum trap is plumbing work that may need a permit; confirm with your municipality (in Calgary, call 311) before planning it.

06 /Is it the tub or the bathroom branch?

It is the bathroom branch, not the tub, when water rises in the tub as the toilet flushes, or when the tub, sink and toilet in one bathroom are all slow. Those fixtures drain into a shared pipe below the floor, and a blockage downstream of all of them backs water up into the lowest opening in that bathroom, which is usually the tub or shower.

• Tub alone slow: tub trap or drain shoe. Snake through the overflow.
• Tub fills when the toilet flushes: shared branch below both. A 1/4-inch cable from the tub rarely clears it; the pro route is a toilet pull with 3/8 to 1/2-inch cable.
• Tub, sink and toilet slow, other bathrooms fine: that bathroom's branch.
• Basement floor drain also gurgles: the building drain or main. See main line vs branch clogs.

The Auger Cable Sizer gives the cable, length and head for a 1-1/2-inch tub line, a 2-inch shower line or a 3-inch toilet branch, and flags when the job should be handed off.

07 /How do you keep a tub or shower drain from clogging?

• Fit a hair catcher over the drain and empty it after every few showers.
• Clean the stopper monthly. Pulling a toe-touch or lift-and-turn stopper takes a minute and removes the hair before it reaches the trap.
• Rinse sand and mud off outside where practical, and use a mesh catcher when bathing a dog.
• Run hot water for a minute after oily bath products to move residue past the trap.
• Skip chemical cleaners. They rarely dissolve a hair mat and they make the next snaking job hazardous.

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