If only 1 fixture in your bathroom is blocked like just the basin, then a blockage has likely occurred somewhere from the basin trap to your main drain in the ground outside. However if a number of fixtures or the whole bathroom is blocking up then, this is usually associated with a blockage in the main house sewer line.
Every bathroom and wet area is required by law to have a floor waste which drains water that is spilt on the tiles.
There are usually 3 diameters of floor waste 50mm, 80mm and 100mm. They can be seen as a grate in the tiled floor. 50mm floor waste grates are called dry floor wastes and are just 90 degree elbows with pipe that drains water from the floor and soaks into the ground outside the building.
80mm and 100mm grates will have a trap below the grate and will be connected to the main house sewer drain.
These floor wastes will have fixtures like basins, showers, baths or sinks running into them. If you run your basin for example and look down the grate you can see the water flowing into it.
These types of floor waste grates can have anywhere between 1 and 4 fixtures running into it. The reason why we’ve explained this is because if your trap in your floor waste (80mm or 100mm) gets clogged with hair, sludge, grease or some other substance or object then it’ll start to block up and as you use the fixtures that run into these floor wastes they will appear slow draining and you may get water rising and overflowing out of the floor waste.
This may be just a buildup of hair or sludge in the trap which will require the grate to be unscrewed and taken out of the insert so you can get down the drain. Getting a bit of wire and twisting it down into the trap below may hook clumps of hair and free the blockage, also dumping a bucket of water from a height into the drain opening could push or clear sludge and free up the flow.
The following are common causes of blockages:
- Hair- Hair can be a common problem particularly in the showers, as hair goes down the drain you can get a buildup in the trap this can cause slow draining of water.
- Soap Scum- This white residue builds up around particles like hair, creating a sludge that fills the trap of the fixtures. It may begin to smell and can attract mold and mildew.
- Galvanised Piping- You will find this steel pipe in older buildings from the 50’s to 70’s. This piping was tough and durable but over time the minerals in the water corrodes away the inside effectively closing the pipe in on itself. The steel pipe may drain into an outside gully. If the gully is overflowing then the blockage is downstream of the gully.
- Foreign Objects- Drains are an attractive place for young kids to poke things down, these objects can cause other substances like hair and soap scum to build up around. If the property is new then construction rubble down the drains can also be a cause for blockages.
- Tree Roots- Tree roots can find their way into pipes through breaks and unsealed inspection caps. Once they enter the pipe they grow rapidly with a constant supply of moisture.
- Broken Pipes- Broken pipes can come about through tree roots squeezing in on them over time, unintentionally hitting the piping with a shovel or other equipment. If the property is relatively new then construction equipment may have damaged the pipe also.
- Bad Installation- Build up in drains or slow draining of pipes can be caused by a bad installation. Back falling drains, reduced grade of piping or dips in pipework cause water and waste to settle in the bottom of pipes and not flow away.