A slow sink is an early warning. Left alone it becomes a blocked one, and a blocked outside drain can back up into the house, which is a far worse morning.
Inside, most blockages are fat and food in a kitchen waste or hair and soap in a bathroom one. Outside, it is more often wipes, roots into an old clay run, or a section that has dropped and no longer falls the way it should.
We clear the blockage and then look at what caused it, because the cause is what decides whether you see us again in a month. If the reason is the drain itself — a collapsed section, roots through a joint, or a run laid without enough fall — that is a different and bigger job, and you are better knowing it than having it cleared over and over.
