Almost every slow shower drain is a hair clog within 100 mm of the grate. You do not need a plumber, and you do not need a chemical: you need to see it and pull it out.
Chemical drain cleaner works by dissolving grease and protein. Hair is keratin, which resists it. What usually happens is the liquid runs past the hair ball, opens a channel through the soap scum around it, and leaves the hair itself as a slippery mass that is now much harder to grip.
Why the hook beats the bottle
A hair clog is a physical object, not a coating. Pulling it out removes 100% of it in one go. Dissolving it depends on the chemical reaching the whole mass, and hair is dense enough that it usually does not.
There is also a safety argument. Caustic drain cleaner left sitting in a trap is a hazard for the next person who opens it, and mixing two different cleaners can release chlorine gas. If you have already poured one in, flush it thoroughly with cold water before you put a hand anywhere near the drain.
The two-minute weekly habit
Once the drain is clear, the cheapest way to keep it that way is a silicone cover that catches hair before it enters the pipe. Empty it after every shower — it takes four seconds — and the clog never forms.
Then once a week, a kettle of boiling water down the drain melts the soap scum that the hair was sticking to. No chemicals, no smell, no surprise on a Sunday night.
If the water still drains slowly
A cleared grate that still drains slowly means the blockage is past the trap. That is a different job with different tools: read the standing-water guide before you start forcing anything through the bend.
Step by step
Each step is one picture. The hotspot marks the part you touch; the caption is the whole instruction.
Cover plate
Lift the cover straight up. No tools needed.
Hair mat
90% of clogs are right here.
Snake barb
Hook it out. Don't push it down.
Twist direction
LOOP · Rotation · 2 frames
Twist the filter counter-clockwise, then lift.
Kettle spout
Pour boiling water to melt the soap scum.
Water flow
Put it back. Test with hot water.
What not to do
These are the four ways a ten-minute job turns into a call-out. Every one of them is a red-bordered figure for a reason.
DON'T
Don't use chemicals first — it turns hair into jelly.
DON'T
Don't push the hair deeper. Hook it, always.
Before you close the page
No snake to hand?
A wire coat hanger bent into a small hook works. Tape the sharp end first.
What good looks like
After the boil, water should drain with a clean swirl and no gurgle at the end.
Never mix cleaners
Bleach plus caustic cleaner releases chlorine gas. One product, or none.
Related guides
The $5 Fix: Installing a Silicone Drain Cover and One-Way Valve
Two parts, ten minutes, no tools. This is the highest-return job on the whole site.
Standing Water: When to Snake, When to Call a Plumber
Water that will not move at all is a blockage past the trap. There are three tests that tell you whether you can reach it yourself.
The 5-Minute Weekly Drain Routine That Prevents Everything
Three habits, five minutes a week. Every problem on this site starts with one of them being skipped.
Safety
Wear gloves and eye protection. Ventilate the room. Never mix chemical cleaners — bleach plus caustic cleaner releases chlorine gas. Trap contents are grey water and may carry bacteria. If water backs up in more than one drain, or you smell gas, stop and call a licensed plumber.