Shower Drain Clogged but No Hair? 6 Other Causes and Fixes

The good news is that these clogs usually sit in the strainer, the pipe just below it or the trap, and you can reach them with a screwdriver, a stiff brush and a drain snake.

Graphic: summary of this guide, made by our team from the cited sources.

Match what you see to the cause

What you notice	Likely cause	First fix
Gray, waxy film on the strainer and tub or tray	Soap curd from soap plus hard water	Brush the strainer and the pipe below it
White, crusty spots on the drain and faucet	Hard water scale	Scrub with a descaler; consider a water softener
Black or brown slime when you scrape inside the drain	Organic film (biofilm)	Stiff brush, then snake; enzyme cleaner after
Grit or sand on the tray floor after showers	Sand, mud or exfoliant beads	Remove the strainer and clear the trap
Drain went slow suddenly	A dropped cap, razor guard or similar object	Look under the strainer; snake or call a plumber
Shower, tub and toilet all slow, or gurgling	Clog further down the line or a blocked vent	Check other fixtures; call a plumber

1. Soap curd from soap and hard water

This is the most common hidden cause. Hard water carries dissolved calcium and magnesium. University of Nebraska-Lincoln Extension says in its hard water guide that soap used in hard water combines with these minerals to form a sticky soap curd, and that the curd deposits on bathtubs, showers and all water and plumbing fixtures.

You will usually see the same gray film on the shower walls or glass. North Dakota State University Extension's page on hard water issues says hard water causes films on glass shower doors, walls and bathtubs, and that soap curds or soap scum form when regular soap combines with dissolved calcium and magnesium. If your shower walls have it, your drain pipe almost certainly does too.

Fix: remove the strainer, scrub its underside, and scrub as far into the pipe as a stiff bottle brush reaches. Then run hot water for a few minutes.

2. Hard water scale

Scale is the hard, white mineral crust that hard water leaves behind. UNL notes that heated hard water forms a scale of calcium and magnesium minerals. NDSU says scale deposits also corrode and plug plumbing fixtures, and UNL notes that pipes can become clogged with scale that reduces water flow. Scale alone rarely closes a shower drain, but it gives soap curd and grit a rough surface to grab.

Not sure if your water is hard? UNL says public water systems must send customers an annual water quality report, called a consumer confidence report. The report may include the hardness of your water, or you can ask your water supplier for it.

3. Slime inside the drain

Soap film, skin oils and shampoo feed a layer of organic slime on the pipe walls. You can check for it the way the University of California IPM program describes on its moth and drain fly page: remove the drain plate and scrape the sides of the drain with a dull knife or similar tool. If it comes up black or brown and slimy, you have found part of your clog. Small flies with hairy, moth-like wings around the shower are another sign of the same film; UC IPM says bathroom drains are their most common breeding site in homes.

UC IPM makes a point most guides skip: pouring boiling water or bleach down the drain does not remove this organic film. It recommends scrubbing with a hard bristle brush used with a drain cleaner, and says drains may need to be snaked first to clear a blockage causing slow draining. It adds that regular use of an enzymatic drain cleaner may help prevent the buildup from coming back.

4. Grit, sand and small objects

Sand from the beach, mud from work boots, exfoliating scrubs and pet baths all leave grit that sinks into the trap instead of washing away. Small objects also slip past a strainer: shampoo caps, razor guards, earring backs. A drain that was fine yesterday and slow today often points to an object rather than buildup.

Shower drains usually have a removable strainer on top. Oatey's guide to all things drains shows shower drains sold with snap-in or screw-in strainers, including a universal 4-1/4 inch round snap-in strainer. Under the strainer, the drain connects to a P-trap. Oatey's No-Caulk shower drain instructions call for 2 inch Schedule 40 DWV pipe connected to the drain P-trap, so the trap sits just below the floor, within reach of a small drain snake.

5. Hair you cannot see

"No hair" usually means no hair on top. Hair that slipped past the strainer weeks ago wraps around anything in the pipe and holds soap curd like a net. Pull the strainer and look down with a flashlight before ruling it out. A plastic barbed drain stick or a small snake pulls it up.

6. A problem past the shower

If only the shower is slow, the clog is in the shower's own drain. If the tub, toilet and sink are slow too, or the toilet gurgles when the shower runs, the trouble is further down. The City of Minneapolis page on sewer problems in the home says slow drainage in toilets, showers and sinks is typically caused by clogs in the property's own plumbing. It also says to check that the stack vents on your roof are not blocked by leaves, snow or ice, and that if your neighbors are having similar problems, a city sewer line problem is possible, though rare.

How to clear it, in order

1. Remove the strainer. Pry a snap-in strainer up from the edge with a flat screwdriver, or take out the screw (or screws) holding a screw-in one. Clean its underside.
2. Look and scrape. Use a flashlight, then scrape the pipe walls to see what you are dealing with: hair, slime or grit.
3. Brush. Run a stiff bottle brush or drain brush down the pipe as far as it goes, then flush with hot tap water.
4. Snake the trap. Feed a small hand auger down the drain and through the trap. Turn it as you go, pull it back and clean it.
5. Flush and test. Run the shower for a couple of minutes and watch the water level.
6. Prevent it. A hair catcher, a monthly brush, and an enzymatic cleaner if slime keeps coming back.

The same steps apply to a tub drain, though the stopper has to come out first. If your shower drain smells as well as drains slowly, our guide to why a bathtub drain smells bad covers the odor side.

Go easy on chemical drain cleaners

Chemical cleaners are not the first step here. Poison Control's article on what is in drain cleaner explains that many contain concentrated acids or alkalis such as sulfuric acid or sodium hydroxide, and that some generate heat when poured down a drain. It warns that a cleaner can splash back if it is poured from too high or if too much is poured into a completely blocked drain. If you use one, wear goggles and rubber gloves and pour close to the drain. Never mix products, and never plunge or snake a drain that has chemical cleaner sitting in it.

Poison Control also says the baking soda and vinegar recipe makes carbon dioxide gas that escapes through the drain cover, and that the mix is unlikely to be strong enough to clear tough clogs from oil and grease. If someone is splashed or swallows drain cleaner, call Poison Control at 1-800-222-1222.

When to call a plumber

• The shower stays slow after you have cleaned the strainer, brushed the pipe and snaked the trap.
• More than one fixture is slow, or the toilet gurgles or bubbles when the shower drains.
• Water backs up into the tub or shower when you flush or run the washer.
• You dropped something solid into the drain and cannot reach it.

If the shower is just one of several drains that clog over and over, see why a drain keeps clogging for how to trace a repeat clog to its source.