Boiling water is the simplest and easiest solution for clearing a drain blockage. This won’t work on trickier blockages, but sometimes it is all that is needed to loosen and clear debris. The simplest fix on the list is often worth starting with boiling water when attempting to clear a sink or shower drain blockage. When dealing with a blockage from hair, grease, or soap scum build-up, boiling water may be all that is needed. Regularly pouring boiling water down your shower drain will help avoid these types of blockages.
If your drain is attached to PVC pipes, the boiling water could damage or melt the pipes. In this case, try one of the other solutions in this guide.