A blocked toilet stops waste leaving the bowl. The water rises when you flush, or it drains away very slowly. Stop flushing at that point, because the bowl may overflow.
Most toilet blockages come from too much paper, wipes or sanitary items. Scottish Water says to flush only pee, poo and toilet paper. It also says to bin all wipes, even if the pack says flushable, because many contain plastic.
The drain from a home to the public sewer is usually about 10 cm wide, which is less than a DVD. It does not take much to block it. Sometimes the blockage sits further along the pipe, so a plunger cannot reach it. However, a drain rod or camera can.
If a bath or sink is also slow, the blockage may be in a shared pipe or the drain outside. In that case an engineer with rods, a snake or a drain camera can find the cause, while a plunger alone will not.
Stop flushing and check whether other drains are slow. This shows whether the blockage is in the toilet or further along the pipe, since a shared pipe slows every fixture.
A plunger or toilet auger can shift a blockage in the pan or trap. Ask the engineer what they plan to use, since strong chemicals rarely help.
If water still backs up, a drain snake or camera can reach the soil pipe and the drain beyond. This finds blockages that a plunger cannot reach.
Flush a few times to check the flow. Then ask what caused the blockage, because that helps you avoid a repeat.
Prices vary because every blockage differs in cause and access. A simple blockage in the bowl is a smaller job than a blockage in the drain outside.
Ask for a written quote before work starts, because it fixes what the price covers. Ask whether there is a call-out charge, since that is a separate cost. Also ask how the price changes if the job needs a camera check or jetting.
A plunger can clear a simple blockage, so it is worth a try first. If the water stays high or the blockage returns, stop and ask an engineer. Strong chemicals rarely shift solid items, so avoid them while you wait.
Flush only pee, poo and toilet paper. Bin wipes of every kind, even those sold as flushable. Many wipes contain plastic, so they do not break down in the sewer, and they can block it.
Your private drain runs from the house to your property boundary, and you are responsible for it. Scottish Water looks after the public sewer, while you look after your own pipe. If sewage is flooding from a public sewer, call Scottish Water on 0800 0778 778.