Both bottle traps and P traps do the same essential job: they hold a water seal that keeps drain smells out of your bathroom. The difference is in how they look, how much space they take up and how easy they are to clean. Here is how they compare.
What Is a Bottle Trap?
A bottle trap has a compact, upright body. Water enters from the top, collects in the base to form the seal and leaves through a side outlet towards the wall. Most bottle traps have a base that unscrews, so you can clear hair and debris without removing the whole trap.
What Is a P Trap?
A P trap is a curved pipe shaped like a sideways letter P. Water runs down, round the bend where the seal sits, and then out horizontally into the wall. Its shape is simple and it gives a smooth flow path.
Appearance
Bottle traps are the usual choice when the pipework is on show, such as under a pedestal, wall-hung or countertop basin. Metal bottle traps in chrome, brushed brass or matt black can look like a design feature. P traps are more often used where the trap is hidden inside a cabinet or behind a pedestal.
Space
A bottle trap is compact and sits close to the wall, which suits narrow spaces. A P trap needs a little more room for its curve, but it can work well where there is depth to spare. Inside vanity units, compact and adjustable traps are often the easiest fit.
Cleaning and Maintenance
Bottle traps are generally easier to clean, because the base unscrews to give direct access. P traps usually need to be loosened at the joints to clear a blockage. On the other hand, the smooth bend of a P trap can be less prone to collecting debris.
Flow
P traps have a smooth, continuous path, which helps water move quickly. Bottle traps change direction more sharply, but for a basin's normal flow this is rarely noticeable.
Height and Adjustment
Many bottle traps come with an extension tube so you can adjust the height to meet the waste pipe. Telescopic P traps can also be adjusted in height and length, which is useful when the pipes do not line up perfectly.
Which Should You Choose?
- Choose a bottle trap if the trap will be visible, if space is tight against the wall, or if you want easy cleaning.
- Choose a P trap if the trap is hidden, if you want a simple and smooth flow path, or if you need an adjustable telescopic design.
Do Not Forget the Size
Basin traps in the UK are normally 1¼" (32mm). Make sure the trap matches your basin waste and the waste pipe it connects to. Our guide to what a basin trap does covers the other trap types and what to measure.
Shop Basin Traps
Compare bottle traps, plastic traps and adjustable designs in our basin waste traps, or explore the full waste and traps range.