Why does a 300mm Access Chamber not have a lid for driveway use?

Access Chambers are installed close to a house, usually on a path or patio near to the top of the drain so they ONLY have the option of a light-duty lid for pedestrian areas such as patios and paths (A15 Rating).

Only a 450mm Inspection Chamber should be used on a driveway or high foot traffic area, and the appropriately rated lid must be used to comply with The Building Regulations.

When and where should an Inspection Chamber be used?

Inspection Chambers are a very important part of an underground drainage system, they provide access for testing and inspecting, as well as clearing blockages.

There are different types of inspection chambers, each with its own intended use and placement, depending on circumstances such as location, depth and foot or vehicle traffic. We’ve created a quick guide below:

Access Chambers

Access Chambers, often referred to as mini or shallow access are used close to a house, and near to the top of the drain, so they’re not fitted deeper than 600mm (0.6m) and have a diameter of 300mm. They provide easy access for inspection and equipment.

*Access Chambers ONLY have the option of a light-duty lid for pedestrian areas such as patios and paths (A15 Rating).

Inspection Chambers

Inspection Chambers are a larger version of an access chamber, usually with a diameter of 450mm to 600mm, enabling them to be installed further away from a house, and to a maximum depth of 1200mm (1.2m). They tend to also have more branches feeding into them.

Inspection Chambers a more versatile so have a choice of compatible lids rated for different applications, for example, driveways etc.


Manholes are larger than access and inspection chambers as they’re designed to be big enough for maintenance staff and equipment to enter the drainage system, they’re usually deeper than 1 metre and wider than 600mm x 900mm and lead to the sewer. They’re kept sealed and not accessible to the public.

How deep can inspection chambers be installed?

Mini Access Chambers (300mm Diameter)

Mini Access Chambers can be used effectively to a maximum depth of 600mm (0.6m), this is simply due to their narrow width. However, as they’re supposed to be installed near the house, they’re close to the top of the drain.

Standard Inspection Chambers (450mm Diameter)

Due to them being wide enough for a child to fall down, Standard Inspection Chambers have a maximum permitted depth of 1200mm (1.2m).

*Using an inspection chamber deeper than 1200mm: In the rare instance that a deeper inspection chamber is required, then a 350mm Chamber Reduction Ring must be used, under these circumstances the maximum depth would be 3000mm (3m).

Can I contact you if I’m having trouble using the website?

Yes, our friendly team are here to assist you with using our website and you can call us on 0161 302 3100 or contact us on Live Chat during office hours (Monday to Friday: 9am until 4:30pm).

Do I have to register?

No you do not have to register but it would be beneficial to you as we would keep you informed of special offers based on items you purchase.

Do you offer trade /credit accounts?

No we don’t offer trade specific prices or discounts as we already offer our very best prices upfront on our website and these everyday low prices are available to all customer whether they’re public or trade.

If I send you a drawing will you be work out what I need?

At the moment this isn’t a service we are readily offering. However, we are hoping to resume this service in the near future.

All the information needed to help you calculate what you’d need can be found in the product descriptions and installation guides.

Do you provide a job specification service?

As we’re an online shop we’re limited in the technical advice that we can offer, we can help you with information provided by the relevant manufacturer but will be limited beyond that. For example we can help with explaining how a particular product is installed for specific drainage requirements but we can’t tell you how to construct the entire system from scratch.

Can I cancel an order?

Once an order has been placed and is processing we are unable to cancel your order and our normal returns policy will apply.

Can I return my leftovers if I over order?

No, unfortunately not, we only accept returns if you change your mind about the whole order and wish to return all the items within 14 days of receiving them, this is in line with your consumer rights providing that the goods were ordered for non-business use.