The S-trap suits floor-connected wastes and was standard practice for decades. Its vertical outlet makes it more vulnerable to self-siphonage: a fast-emptying basin can suck the trap's own seal out with the last of the water.
Modern standards manage this with venting rules and trap design, but plenty of older S-traps still gurgle and smell for exactly this reason.
Provides a fixture water seal where the drain connection is in the floor.
Older bathrooms and kitchens with floor-penetrating waste pipes.
A CCTV drain inspection is the standard way to confirm whether this is what's happening in your pipes: the camera shows the condition on screen, a locator pinpoints the exact position and depth, and you get a recorded report before any repair decisions are made.
A CCTV drain inspection shows exactly what's happening inside your pipes — no guesswork.