What is a catchpit? Catchpit chambers explained

When installing a drainage system, a key consideration is how to prevent debris from entering and blocking the pipework. This is where catchpits come in.

These simple yet effective chambers collect silt, leaves, and grit carried by surface water, helping to prevent blockages and reduce the risk of system failure.

In this blog post, we’ll answer the question ‘what is a catchpit?’, explain how they work, where they’re commonly used, and what materials they are made of.

We’ll also introduce our Accesso catchpit products, a smarter, ready-to-install solution that’s trusted by contractors and specifiers across the UK.

What is a catchpit?

A catchpit is a chamber designed to trap silt, debris, and other solids carried by surface/stormwater. It prevents these materials from reaching and clogging downstream drainage components.

They effectively remove 30-50% of suspended solids, particularly coarse particles over 500 µm, making them a reliable first step in sediment capture.

Typically installed at low points, such as beneath road gullies or in line with pipework, catchpits allow heavier particles to settle at the bottom, while cleaner water exits through an outlet pipe positioned above the sediment level.

Their design simplifies maintenance and helps keep the wider drainage network running efficiently.

Where are catchpits used?

Catchpits are found in a wide range of drainage applications, including highways, car parks, commercial developments, and residential projects. Wherever runoff is likely to carry debris, catchpits serve as the first line of defence.

They are commonly placed upstream of critical components like soakaways, attenuation tanks, or infiltration systems, acting as a safeguard that reduces blockages and prolongs the performance of the system.

They are especially valuable in urban environments with large impermeable surfaces, where high volumes of runoff can quickly overwhelm unprotected drainage systems. In flood-prone areas, catchpits also contribute to resilience by maintaining flow capacity during heavy rainfall events.

What are catchpits made from?

Traditionally, catchpits were made of concrete, a durable material that is heavy, labour-intensive to install, and not always the best choice for modern drainage schemes.

Today, an increasing number of projects use plastic catchpits made of HDPE (High-Density Polyethylene) LLDPE (Linear Low-Density Polyethylene).

These modern alternatives have numerous advantages: they are strong, resistant to corrosion and chemical damage, and much easier to handle on-site. Their lightweight design enables faster installation, fewer plant requirements, and lower overall project costs.

The Accesso catchpit range: a smarter drainage solution

At Turtle Enviro, we’ve redefined what a catchpit chamber can be.

Our Accesso catchpit product is a smarter, more efficient alternative to traditional systems, created with installers, specifiers, and end users in mind.

Made from tough, lightweight HDPE or LLDPE, our Accesso chambers are factory-built and delivered to site as one complete unit, ready to install with no on-site assembly required. This significantly speeds up installation time and reduces labour costs, with no need for heavy lifting equipment.

Each chamber is designed to perform. Integrated silt sumps help trap sediment and debris before it reaches the wider system, and larger chamber sizes offer increased capacity, up to 90 litres, making maintenance easier and more effective.

Our catchpits are built to meet key industry standards, including Design & Construction Guidance (DCG) for Type D & E chambers, and BS EN 681-1. Selected models, such as our 600mm Accesso unit, are suitable for adoptable sewers.

With a wide range of sizes, invert depths, and pipe configurations available, Accesso chambers are trusted by contractors and specifiers across the UK to provide high-performance drainage with less hassle on-site.

Explore our full Accesso range or contact our team for technical details, spec sheets, or a tailored quote.