Water traps
Everything you need to know about Purus water traps – function, types, and benefits
- Why is a water trap needed in the floor gully?
- Some of Purus most common water traps
- How does a water trap with NOOD function work?
- Advantages and disadvantages – plastic vs. stainless steel water trap
- Cleaning and maintenance of water traps
- Replacing or upgrading water traps – find the right model
- What is an untrapped gully?
Why is a water trap needed in the floor gully?
The water trap is one of the central parts of a floor gully. You can see it when you lift off the grating. It prevents bad odours, moisture and gases from the sewage system from penetrating into the room. The seal is created by a small water pocket that acts as a barrier against unwanted odours – a simple but crucial detail for a healthy indoor environment.
Purus is the market leader in floor gullies and water traps in the Nordic region and has been developing robust, reliable products for over 80 years. Our solutions are adapted to Nordic building traditions – they are durable, easy to maintain and built to last for generations.
“It prevents bad odours, moisture and gases from the sewage system from penetrating into the room”
Different types of water traps from Purus
Purus offers a wide range of water traps that suit different environments, load levels and floor gully models:
- Plastic water traps – Lightweight, affordable and easy to clean, some of which can be split. Most common in homes, bathrooms and laundry rooms.
- Stainless steel water traps – Extremely durable and hygienic, ideal for commercial kitchens, public premises and industrial environments. The stainless steel material also acts as an effective protection against pests that could otherwise get in through the sewage system.
- NOOD water traps – A mechanically spring-loaded solution that closes tightly when the water dries out. NOOD stands for “NO ODour”. This means that NOOD prevents odours from the drain from seeping through even if the water in the water trap has evaporated for a longer period of time without a water supply. Perfect in spaces where the floor gully is used infrequently or irregularly over the seasons of the year, such as holiday homes, hotel rooms or basements. Models with a locking ring ensure that the water trap does not come loose and can withstand up to 1 m of water column, which is great when heavy rain can cause flooding in basements, for example.
How does a water trap work with NOOD?
The illustration below shows how the NOOD lock, a Purus invention, combines a classic water trap and a mechanical odour trap for double security. The NOOD lock provides effective protection against backwater, bad odours and pests. The spring-loaded bowl always closes tightly against the top of the water trap when there is no water supply. Available in both plastic and stainless steel.
The weight of the incoming water flow causes the water trap’s centered spring mechanism to open, allowing the water to flow through unhindered into the gully.
The illustrations show the water trap in cross-section and are based on the NOOD water trap model with locking ring for Ø150 mm floor drains, RSK 7138448
When there is no water supply, the water trap closes automatically and seals tightly against the outlet. Here the water trap is seen in the closed position, with a small amount of water remaining in the lower part, just like a regular water trap with a water mirror.
If the floor gully is left unused for a longer period, the excess water will evaporate after a while. NOOD’s spring mechanism then keeps the water trap closed against the floor gully and prevents unwanted odours from penetrating through and up into the room.
Advantages and disadvantages – plastic vs. stainless steel water trap
Material | Advantages | Disadvantages |
Plastic water trap | Durable, cost-effective, easy to assemble and clean, especially the divisible models, available in many variants to fit different models of floor gullies. | Less resistant to prolonged high temperatures, but can withstand temporary temperatures of up to 90 degrees. |
Stainless steel water trap | Extremely durable with high mechanical resistance, resistant to heat and chemicals, and protects against pest attacks. | Slightly higher purchase cost, but significantly longer lifespan. |
Cleaning and maintenance of water traps
Purus water traps are designed to be easy to clean without tools. As a rule, it is enough to lift the insert, rinse with warm water and a detergent if necessary.
Water traps that can be divided are easiest to clean after they have been divided, the parts should then be cleaned separately and reassembled.
If you have a water trap with a mechanical NOOD odor stop or a Ran water trap, these are not divisible. Here, you can keep the parts apart, rinse them under warm water and brush them with a dish brush or an old toothbrush together with detergent.
When reassembling the water trap insert, it is important to ensure that the gasket is in its groove, otherwise sewage odors may risk seeping through the gap. Lubricate the water trap seal with dish soap, soap solution or special silicone and then reassemble it in the floor drain.
Hydrogen peroxide can discolor PVD-coated products.
If you have a stainless steel water trap, it may be good to know that ferrous objects such as hair clips that have been left on the stainless steel surface for a while have discolored and caused corrosion. Small superficial rust spots do not mean that the stainless steel has corroded. As a rule, minor stains can be rubbed off with a scouring pad and mild scouring powder.
Regular cleaning of the water trap gives a longer life, improves the flow and reduces the risk of odour.
Replacing or upgrading water traps – find the right model
Do you need to replace the water trap in an older Purus floor drain? No problem.
We offer spare parts and replaceable water traps for all our floor gully models and dimensions. Thanks to our standardized design, several variants often fit in the same gully, making it easy to find the right solution even for older installations that are discontinued and can no longer be ordered.
We are happy to guide you in finding the right spare part for older floor drains. First, we would like to receive pictures that can help us see which model you have on your floor golly and then see what common spare parts in the form of water traps and O-rings for older Purus floor gullies we can offer.
What is an untrapped floor gully?
An untrapped floor gully is a floor gully without a water trap, where the water flows straight into the drain. They are often used in garages, boiler rooms, industrial premises and commercial kitchens – environments where quick drainage and easy cleaning are more important than an odour barrier.
It is most often because the water trap dries out easily that people choose a floor gully in sauna areas. Here we recommend a water trap with a NOOD function instead, which is a better alternative because you avoid unwanted odours from the drain even when the water has evaporated.
Floor gullies are often installed as part of a system of gullies, channels and drain pipes that together provide high flow capacity and easy cleaning. These systems usually open into a collection gully with a water trap, which acts as an odour barrier for the entire installation.
Purus – the largest supplier in the Nordics in floor gullies, water traps and accessories
With over 80 years of experience, Purus is the Nordic countries’ leading manufacturer of floor gullies, indoor drainage systems and other plumbing products that ensure good drainage.
We offer the market’s widest range of gloor gullies, water traps, floor channels, untrapped gullies, extension rings, spare parts and accessories – developed to meet the requirements of both small and large projects.
Whether you are building new, renovating or maintaining existing installations, you can trust that Purus has a solution that combines durability, function and safety – adapted to Nordic conditions and future requirements.
Summary – why you should choose Purus water traps
- Market leader in floor gullies and water traps for over 80 years
- Adapted to high demands from Nordic building traditions and requirements
- Wide range in plastic, stainless steel and patented NOOD odour traps
- Fits all Purus floor drains and dimensions
- Robust construction with long service life
- Easy cleaning and access to spare parts
- Safe choice for both professional installers and private individuals
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