November 17, 2025
Behind every neat, odour-free basin, there is one small fitting doing a lot of quiet work – the bottle trap. Choosing the right bottle trap for a wash basin is not just about clearing water. It affects smell control, cleaning effort, and the appearance of the area below a counter or wall-hung basin over time in Indian conditions.
This guide focuses solely on bottle traps, utilising Watertec’s catalogue-backed range to demonstrate what to check before purchasing and how to match model type, size, and finish to your bathroom.
What is a bottle trap for a wash basin?
A bottle trap is a small trap unit which is fitted under the basin for hand wash, and it keeps a water seal that stops bad smells from the sewer while the water from the sink can flow freely. The bottle trap has the seal in a vertical chamber; thus, the straight tube can be directly connected to the wall outlet without the need for a long-swept bend of a P-trap.
The result is:
A tidier cylindrical body that looks better in exposed installations
A bottom or side clean-out that can be opened for periodic cleaning
A compact footprint that suits wall-hung and top-counter basins, where the trap is visible
In premium homes, hotels, and show bathrooms, this “under-basin” visual becomes part of the design, not something to hide.
Types of Watertec bottle traps in the catalogue
In Watertec’s BAFT Cromo range, two main bottle trap families are relevant for a bottle trap for a wash basin, where appearance and build differ by use and budget:
C.P. Bottle Trap Light with S.S. Pipe (5 x 12 and 7 x 12)
C.P. Bottle Trap Heavy with S.S. Pipe (5 x 12 and 7 x 12)
Both versions use a chrome-plated (C.P.) body with a stainless-steel extension pipe, but the Heavy version has a more robust construction and presence, which suits high-visibility or high-use areas.
Light versions are ideal for smaller powder rooms or where a slimmer profile is preferred. Heavy versions feel more substantial and align well with premium mixers and fittings.
How to choose bottle trap size: 5 x 12 vs 7 x 12
The size markings in the catalogue (5 x 12 and 7 x 12) are about proportion and reach, not just a random label.
The “5” and “7” indicate the approximate diameter and body proportion of the trap
“12” refers to the stainless-steel extension pipe length suited for standard wall outlet spacing
For compact vanities or tight knee space, a 5 x 12 C.P. Bottle Trap (Light or Heavy) keeps the assembly more compact under the basin. Where the basin for hand wash is larger, the counter is deeper, or the trap is more visible, a 7 x 12 variant fills the space visually and makes the under-basin zone look deliberate and balanced.
The practical approach is:
Shorter projection or smaller basin: pick a 5 x 12
Larger projection or more “exposed” design: pick a 7 x 12 for better proportion
Light vs Heavy: which build suits your project?
Watertec lists separate MRP entries for C.P. Bottle Trap Light with S.S. Pipe and C.P. Bottle Trap Heavy with S.S. Pipe in both 5 x 12 and 7 x 12 sizes. The difference is in feel and robustness.
Choose Light when:
You want a clean C.P. finish without a very chunky look
The basin is compact, and the trap sits closer to the cabinetry
The bathroom sees light to moderate daily use
Choose Heavy when:
The trap is fully visible under a wall-hung or open counter basin
The site is a hotel, office, or a frequently used family bathroom
You want a more substantial, “solid” aesthetic to match heavy mixers and premium bathroom fittings
In both cases, the C.P. finish and stainless-steel tube pair well with other chrome bathroom elements such as mixers, angle valves, and waste couplings from the same Cromo family.
Sizing and connection: getting the fit right
For a trouble-free installation, match the bottle trap to the rest of the drain line:
Inlet compatibility: Standard basins typically use 32 mm waste. Pair the bottle trap with Watertec’s 32 mm C.P. waste couplings (full or half thread) from the same Allied section so threads, nuts, and seals work as a single set.
Outlet reach: The 12‑inch stainless pipe length in the 5 x 12 and 7 x 12 sizes is tuned for typical Indian wall outlet positions. If your outlet is unusually far or high, your plumber should confirm reach and choose the right offset or extension, still staying within the Watertec family for finish continuity.
Seal height: The Watertec bottle trap body maintains an adequate water seal depth for regular basin for hand wash, which helps hold the seal even in air‑conditioned powder rooms with intermittent use.
Installation tips for odour-free performance
A good bottle trap for a wash basin is only as reliable as the way it is fitted. Practical on-site steps:
Use matching Watertec washers and nuts from the same Allied range so the C.P. body, S.S. pipe, and waste coupling interface cleanly.
Align the stainless-steel pipe in a straight run to the wall outlet, avoiding improvised bends that can trap debris.
After tightening, run water and check for drips at three locations: waste coupling joint, bottle body joints, and wall outlet.
Leave the clean-out section accessible, not buried behind fixed panels, so periodic cleaning takes minutes, not hours.
These steps protect both smell control and the chrome finish by avoiding unnecessary rework later.
Design and coordination with other bath fittings
The C.P. Bottle Trap Light and Heavy lines are part of a larger Cromo ecosystem of taps, mixers, and accessories. This makes it easier to create a coherent look:
Pair the trap with C.P. waste couplings and floor traps from the same catalogue, so all visible metal elements read as one family.
In a design-led bathroom, align the bottle trap diameter (5 or 7) visually with the scale of the basin for hand wash and the underside of the counter.
For projects using Watertec wall mixers, angle valves, or shower sets, the common chrome language across all items produces a consistent aesthetic story with fewer finishing surprises.
Why shortlist the Watertec bottle traps for wash basins
Watertec’s Allied section clearly lists C.P. Bottle Trap Light and Heavy options with stainless-steel pipes and matching accessories such as waste couplings and PVC waste pipes. For an architect, contractor, or homeowner, this means:
One catalogue for the entire under-basin ecosystem
Factory-tuned proportions for standard Indian site dimensions
Matching finishes with other bathroom fittings in the same project
Because the system is designed to work as a set, installers spend less time improvising and more time delivering a clean, odour-free result.
Conclusion: Treat the bottle trap as a visible component
The under-basin zone is no longer a place to hide fittings. Treat the bottle trap for the wash basin as a visible, functional component that deserves the same attention as mixers or mirrors. Choose between Watertec’s C.P. Bottle Trap Light and Heavy in 5 x 12 or 7 x 12 based on space, usage, and visual balance.
Match them with compatible C.P. waste couplings and pipes from the same catalogue, insist on clean installation with checked joints, and keep the clean-out accessible. With that, a small fitting quietly protects hygiene, finish quality, and the overall impression of your bathroom for years.
