Branch & fixture drains

What makes it a branch

If one fixture is slow and nothing else in the house is affected, the restriction is between that fixture and the point where its pipe joins everything else. That is a couple of feet to a couple of dozen feet of small pipe, and it is a fundamentally different job from the main line under the lawn — different machine, different time, different price. Anybody bundling the two together at the front door is not diagnosing.

The usual suspects, by fixture

The slow drain that is not a blockage

Drains need air. A vent lets air in behind the water so the pipe can fill and empty; without it, the water pulls a vacuum and the drain glugs, runs slowly, and sometimes siphons the trap dry — which is the point at which a bathroom starts to smell, because the trap seal is the only thing between you and the drain.

A blocked or badly arranged vent produces a slow drain with a distinctive gurgle, and a cable put down that line will find nothing and fix nothing, and you will still have paid for it. We listen for it before we start the machine, and a roof vent is a perfectly cablable thing in its own right if that is what it turns out to be.

One warning about what is in the cupboard

Please do not pour a caustic opener into a fully blocked fixture and then call somebody. It rarely gets through a packed trap, it sits in standing water, and the person who opens that trap is going to meet it with their hands and their face a foot away. If it has already gone in, just say so when we arrive — nobody minds, and it changes how the job is set up.