A plastic drain snake (zip-it tool) or a wire hanger. The Cost: $3–$5. How to do it: Push the barbed tool down the drain, twist it, and pull it up. You will pull up a disgusting, wet "rat" of hair and sludge. This solves 90% of shower clogs instantly.
For homes with septic tanks, bleach can kill the beneficial bacteria needed to break down waste, leading to system failure. Safer and More Effective Alternatives will bleach unclog a shower drain
It cannot effectively cut through the thick grease from body oils or the solid mineral deposits found in soap scum. A plastic drain snake (zip-it tool) or a wire hanger