What are waterless traps?

Steve Skeldon, Above Ground Product Group Manager at Wavin, explores how the latest innovations are transforming modern plumbing.

When it comes to household plumbing, the role of the trap cannot be understated. Installers are familiar with its traditional, distinctive U-shaped design – but is it still the best option to respond to the challenges posed by modern housing and its relevant maintenance?

The residential floorspace in new builds is getting smaller, and this is already defining urban and residential developments and presenting challenges onsite. While essential, when it comes to plumbing maintenance and installation, traditional traps present challenges – particularly in those properties with limited space.

Waterless traps are now recognised as a key alternative, offering greater flexibility, easier installation, and better performance.

The limitations of water-filled traps

Traditional water-filled traps play a vital role in preventing foul smells and gases from entering living spaces. However, they rely on a design that retains a water seal in a pipe run. This acts as a barrier against foul gases entering the building, but this can be prone to failure, begging the question – is this method still the best fit for today’s demands?

Installers and plumbers know that the choice of a trap largely depends on the project at hand. Innovations across the market have made this possible with common variations like ‘P’ and shallow traps being ideal for different applications such as under kitchen sinks and beneath bath or shower trays.

With minimal use, water can sit idle, dry out, or evaporate, compromising the seal and allowing foul odours to escape. In vacant properties, trapped water can also evaporate resulting in the loss of the crucial seal – this is especially common in holiday homes which lay empty for longer periods, or homes which are slow to sell.

Traditional U-bend designs have flaws too. A big issue here is potential blockages, which are often caused by common culprits like discarded food, cooking oil, and hair becoming lodged in the bend. Ultimately, failures can become real pain points for end-users, so it’s important that installers know there are alternative options.

The ideal alternative

Waterless traps are quickly becoming a go-to choice, offering an alternative to a traditional water-seal. Instead of relying on water to block the flow of sewer gases, these innovative traps use a soft silicone rubber membrane to create a seal, instead of ‘trapped’ water. The self-sealing valve opens when water flows through and closes once it stops, creating a reliable seal without the need for water.

This design brings immediate benefits. The absence of water prevents stagnancy during periods of limited use, and eliminates siphonage, which in turn better protects homeowners and residents from the foul odours and smells of sewage below – a critical job for a trap.

But the advantages don’t stop there. Many waterless traps remove the need for the cumbersome U-bend design, guaranteeing more flexibility and versatility during installation. With the U-bend removed, these can be installed either vertically or horizontally and are suited for a wide range of applications. For example, waterless traps like Osma HepᵥO, make installation simpler and faster – whether it’s under a sink, in a shower, or beneath a bath – saving both time and resources for installers on the job.

Making the switch

Swapping to a waterless alternative has never been easier, with many of today’s traps specifically designed for easier, quicker installations.

They’re not just for new installations either, as they work just as well in existing set ups. Installers can remove the pre-existing trap and reattach the waterless alternative to the knuckle-bend adaptor – and the system is ready for use. Solutions which offer this streamlined, quick installation are invaluable for installers jumping from job to job.

While some may continue to rely on the products they’ve experienced and are comfortable with, it’s important not to overlook innovations that can offer greater efficiency and performance.