Looking for the best solution for a catchpit tank, but need a better idea of costs first?

The biggest concern when installing catchpits to a bespoke size using precast or in situ concrete is that it can be time-consuming and expensive.

The good thing about catchpit tanks is that they’re often mass-produced at around 2m (l) x 2m (w) x 2m (d), which means that if that’s what you need, they can work out to be very economical.

However, when they’re bespoke, they’re not so competitive in price to be constructed with in situ or precast concrete. Depending on the size, this will impact on the time it’ll also take to install with precast or in situ, whereas prefabricated steel is extremely fast to install on-site.

So, how much should a catchpit tank cost? Well, as a specialist subcontractor who specialises exclusively in prefabricated steel, I’m going to explain more below.

How much should a catchpit tank cost?

All prefabricated steel catchpit tanks are built to be entirely bespoke depending on your specific project, and your individual requirements – not to mention the size and complexity of your catchpit tank.

I’ve talked about typical costs of prefabricated steel substructures (which can include catchpit tanks) in a previous blog, so we’re looking at around £800 – £3,000 per sq. metre.

Now, I’m aware that’s quite a wide range – and may not be the most useful information – which is why I wanted to share a real-world example of a catchpit tank we built for Wide Lane, Southampton.

In this example, we constructed a catchpit tank measuring in at at 2m wide x 4m long x 4m deep, for a cost of between £20,000 – £25,000.

What other factors can affect cost?

One thing to bear in mind about prefabricated steel catchpit tanks is that they can become more economical the larger and more complex they become. This includes the amount of drainage connections required, and the quantity of wiers to allow the water to filter.

A significant factor to take into account when building a substructure to be used as an catchpit tank, is that it’d have to be built using stainless steel – this eliminates any rusting or corrosion issues later down the line, and may mean your catchpit comes out on the higher end of the price range I mentioned above.

TIP: Building with stainless steel can still save you money over other traditional methods such as in situ concrete, as I’ve outlined in this blog.

So, even if a prefabricated steel catchpit might work out as more expensive than in situ, for example, you could still save 70 – 80% of time spent on-site; not to mention other elements such as long-term costs that come from leaks, cracks and other issues.

TIP: Prefabricated steel catchpit tanks are welded together in an off-site factory environment, a bit like the hull of a ship – meaning they’re 100% watertight. They’re also built to much tighter tolerances than in situ or precast catchpit tanks.

In the case of Wide Lane, we were approached by our client Winvic Construction, the installation of the catchpit tank went smoothly, with all invert levels of the connections were installed off-site, and ladders and manholes were then refitted.

Due to the size of the catchpit tank, we were able to construct it in one piece in our factory. It was installed in just five days. A big bonus is that it’s 100% watertight and de-risked an extremely difficult activity the on-site construction team would have faced when building it in situ.

Advice from a specialist subcontractor

The generic way of constructing these is to use precast concrete or GRP. Catchpits also tend to be readily available to buy in standard sizes. However, if you require a bespoke structure with non-standard sizes, we’d recommend considering prefabricated steel.

In Wide Lane’s case, our client was aware that building using either with in situ or precast concrete may have caused problems on-site along with long-term leaking and quality issues, so we discussed the best material to build the catchpit out of to ensure it was going to be economical.

If you’re interested in the idea of prefabricated steel for your catchpit tank, but are still feeling uncertain if this is the right choice for your project due to costs, the best thing to do is to get in touch with us directly.


Well, there we have it! I hope this blog has managed to give you a better idea of costs when it comes to prefabricated steel catchpit tanks.

I’d recommend taking your time and comparing your options, and getting a quote that takes into account the specific requirements of your project – including everything from design right the way through to installation – would probably be a good next step.

We can issue you a budget and not only give you a better idea of costs, but also explain more about the benefits of a higher tolerance, speed on-site and long-term waterproofness compared to in situ and precast concrete.

In which case, I’d urge you to get in touch with me directly. Alternatively, if you just have a question, feel free to leave me a comment below. I promise to reply!