Shower drains often become clogged with the hair, dirt, soap scum and other elements that wash down the plughole as you shower. When the shower drain is blocked, water empties more slowly, leaving dirty standing water in the shower for long periods. Fortunately, removing the blockage from the drain is usually straightforward.
Pour 1/2 cup of baking soda followed by 1/2 cup white vinegar down the shower drain. When the vinegar reaches the baking soda, it produces a foam reaction. This foam works through the drain, breaking apart the blockage while also cleaning the walls of the pipes. Allow the foam to work for around 15 minutes.
Pour around 5 litres of boiling water down the drain to flush out the blocked residue down the main waste pipe.
Use a plunger if the boiling water is not emptying properly. Place the plunger over the centre of the drain and plunge vigorously for 30 seconds or so. Run hot water down the drain to rinse out the broken up residue and also to check for any remaining blockage.
Push a pipe snake through the shower drain if you can't shift the rest of the blockage. Buy snakes from home improvement centres, hardware shops and builder's merchants. They are designed to easily push through drains and break up clogged residue. When you feel the snake hit the blockage, push the snake back and forth a few times until you break through it. Flush the drain with hot water to rinse down the residue.
Use a hair trap over the drain opening to catch hair and larger chunks of residue.