Concrete vs Plastic inspection chambers

Well-designed surface water drainage systems with high quality components help support natural surface water cycles by collecting and conveying water while preventing water buildup and, eventually, flooding.

A key part of any drainage system is the inspection chamber, also known as a catch basin. Other than acting as a connection to stormwater systems and sewers, inspection chambers serve two major functions:

  1. They collect surface water. When water accumulates on roads, pavements, and other surfaces, inspection chambers are placed at low points or areas prone to accumulation to capture this surface water.
  2. They help prevent flooding. A catch basin ensures that excess water is removed, reducing the risk of water damage to properties.

Inspection chambers can store water and dispose of them by conveying them to the adequate pipes and channels. In addition, they facilitate the maintenance and repair of water drainage systems

The benefits of siphonic rainwater inspection chambers

Siphonic inspection chambers carry two major benefits over their non-siphonic counterparts. First, the rapid drainage and reduced standing water helps minimize bad smells, preventing them from reaching the surface/opening.

Secondly, siphonic inspection chambers require less maintenance and are easily opened and cleaned with their removable covers.

PVC or concrete inspection chambers: which to choose?

Just like most components of a surface water drainage system, rainwater inspection chambers differ in characteristics such as the material with which they are made. Just a few decades ago, concrete was the choice of material while, today, modern construction practices prefer plastic.

There is a reason for this - PVC and polypropylene carry a number of benefits over concrete when it comes to inspection chambers:

  • They are lighter and hence easier to transport
  • Their weight also makes them simpler to install, reducing installation times and labor costs
  • They are resistant to mechanical stress and have significant chemical resistance
  • They allow for the use of plastic covers and grates, which are safer and easier to handle than concrete manhole covers
  • They are more eco-friendly and can be reused and recycled
  • They are cheap

The technical characteristics of plastic rainwater inspection chambers

The structure of inspection chambers anticipates the insertion of pipes of various sizes on all four sides, with pre-cut circular sections that are designed to be easily broken or removed to connect the required drainage pipes and fittings.

Based on their typical use and the interventions they are installed for, rainwater inspection chambers come in various sizes and configurations. The upper part of the inspection chamber has a customizable frame that accommodates covers or grates for draining water at various flow rates. This allows for usage in pedestrian or vehicular areas with different levels of traffic. The design ensures the chamber can withstand a range of mechanical stresses.

Inspection chambers from the Dakota Group catalogue

Dakota Group is a building materials supplier that offers a wide range of products, including an extensive range of drainage supplies. Within our Drain Catalogue, there is an ample selection of inspection chambers to choose from. Additionally to the catch basins, we offer a series of accessories such as covers, grates, and frames. We also offer extensive channel drainage solutions.

Trusted by over four thousand customers, our plastic inspection chambers are a compelling alternative to traditional concrete chambers.

Our inspection chambers vary in dimensions from 200 to 700 mm per side. They come equipped with pre-cut circular sections that are designed to be easily broken or removed to connect pipes. 

There are seven major inspection chambers in the Dakota Catalogue:

Inspection chamber "Pluviale"

Designed for the collection and horizontal outflow of rainwater, it is equipped with a bulkhead which allows for perfect siphoning. Like all our inspection chambers, it can be fit with a wide range of covers and frames.

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Designed for the collection and vertical outflow of rainwater, it is equipped with an anti-reflux tilting bulkhead, removable anti-fall and inert collection basket, counterthrust perimeter pilasters, access points with multi-diameter predisposition (80-125 mm), customizable open-close lid, outlet coupling fitting 100/110mm diameter downpipe, and a descending end stop.

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Made of light gray polypropylene, it is light, resistant to impact, practical, and compact. It can be stacked, making it easy to transport. Dimensions available vary from 200 x 200 to 550 x 550 cm. Generally, it is used to house electric cables.

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Made of gray polypropylene, it is offered in dimensions ranging from 200 x 200 to 300 x 300 cm. It is light and can be installed by a single person. It is resistant to UV rays, first, and crystallization.

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Made of gray polypropylene, it is available in dimensions ranging from 200 x 200 to 550 x 550 cm. It is reinforced laterally with a ribbed design, yet it remains lightweight and easy to install.

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This inspection chamber has an airtight seal and plugs on the bottom. It is available in 250 x 250 mm and is commonly used to house electrical junction boxes or other electrical components. Thanks to the gasket kit, it guarantees airtightness and hence protection from water. 

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Made of polypropylene. Its dimensions are 735 x 735 x 650 mm and its weight is under 25kg. It is extremely resistant and practical, with the bottom designed for drilling. It is suitable for housing hydraulic and electrical devices for grounding systems and can be lifted by a single person, without the use of a crane. It is our most popular inspection chamber from the Drain catalogue.


As your supplier of building materials, Dakota Group commits to providing you with high quality products and an exceptional post-sale service. By choosing us as a drainage supplier, you benefit from the wide range of products we offer within each construction system, including our modern and high performance drainage systems. Discover why efficient drainage systems matter.

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