This depends on the nature of the blockage. If it’s a minor blockage, as is often the case in toilet basins, it can often be fixed yourself. If it’s a major blockage or blocked sewer line, you’ll need to call a plumber.
This is because sewer line blockages are often clogged up with non-flushable objects like tree roots. Therefore, any DIY attempts to clear the blockage using conventional DIY techniques are likely to cause damage to the sewer lines which end up costing you an arm and a leg to repair. It can also cause your property to become exposed to raw sewage, and nobody wants that.
If you’re unsure, it’s best to play it safe and call a professional. Plumbers like AEB Heating & Plumbing Services can identify whether or not your sewer line is blocked and carry out a safe fix.
