If your toilet cistern fills up promptly after a flush but the bowl is slow to drain, then there is likely to be a partial blockage that is creating a bottleneck. Sometimes this problem will disappear of its own accord after a couple of flushes. Remember not to flush again until your toilet's bowl is at its usual level, or you may end up with overflowing water into your bathroom. However, if the problem persists, then you may need a blocked toilet plumber to help you. What can you do in the meantime?
Operate a Plunger
When you use a plunger on a toilet bowl, you are changing the pressure in the U-bend, thereby forcing the blockage back and forth in small increments until it clears. Householders should always have a toilet plunger at their disposal to clear such issues. Sink plungers have a different design and won't work on a poorly flushing toilet. Remember that you may get splashed doing this and that fixing the problem can take some time. As such, getting a blocked drain plumber in to do the work for you is often advisable.
Rod Your Drainage Pipes
If working with a plunger has failed to resolve the problem, then you will need to inspect your drains to see if your wastewater is free-flowing or not. Lift the manhole cover of your inspection pit. If you see standing or slowly draining water, then you will need to insert push rods into the drain until you can force the blockage apart. Twist the rods clockwise so that they don't unscrew from one another underground. This is hard work and will mean you inevitably get dirty with foul water. A blocked drain plumber will usually be able to rod a clogged-up drain in minutes, but it often takes much longer if you are not experienced in this sort of work.
High-Pressure Blockage Jets
When a blocked sewer drain is so severe that little is passing through and drainage rods have not worked, an alternative method will be needed to resolve the issue. Most good blocked drain plumbers will carry a high-pressure water jet device they can insert into your drains. These force their way along pipes by squirting out water supplied under pressure from a hose. When they reach blockages formed by nappies, sanitary items or congealed fat, they can blast their way through, thereby allowing your drain to flow freely once more. This will also mean your toilet begins to flush properly again.