Attenuation Tank Cost UK: Price per m³ Direct From the Manufacturer

Priced per m³, showing the merchant markup openly – this is factory-direct FOB, not from a UK reseller buying someone else’s crates.

Get a Costed FOB Quote

Published ranges from UK suppliers and cost guides indicate that an attenuation tank costs around £200-350/m for a geocellular crate system, against £280-600/m for precast concrete and £300-500/m for GRP. That crate accounts for just £70-150/m of that figure . This cost guide aims to set that expectation early: while those figures provide a broad indication, only a site-specific costed quote based on your storage requirements and ground conditions can tell you the definitive number for your project. Working on a project, rather than just a driveway? This guide breaks down the per-m price by material, clarifies the position of the UK merchant markup and costs out the ancillaries that typically boost the initial crate invoice by 25-40% – details on surface runoff, flood risk and rainwater harvesting can be found on the main pages this cost guide serves.

Attenuation Tank Installation Cost and Manufacturer Direct Crate Pricing
95% Void ratio (usable storage)
£200–350 Installed cost / m³ (geocellular)
D400 Load class to EN 124 / SLW60
50+ yr Design life (Virgin/Recycled PP)
1 m³ Flexible MOQ, FOB direct
330 m³ Per 40HQ container load

What Drives Attenuation Tank Cost — The Five Price Levers

Often when a buyer asks “what does an attenuation tank cost per m?”, they expect a single, definitive figure. In reality, the modular crate forms the least significant line item on any invoice. In fact, the storage volume, site ground conditions and necessary ancillaries are the key drivers that will have far more impact on the total project cost than the crate itself. Get these five critical levers correct at the design stage and the project cost estimates you receive from contractors will be far less of a surprise.

LEVER 01

Storage volume

Sized to impermeable catchment area, rainfall and the discharge rate your LLFA permits. Per-m³ rates fall 15–25% once a scheme passes ~20 m³.

LEVER 02

System & material

Geocellular crate vs precast concrete vs GRP. This choice alone doubles the per-m³ rate — see the cost ladder below.

LEVER 03

Ground conditions

Clay, high water table or rock can double excavation cost and add dewatering or a concrete surround for buoyancy.

LEVER 04

Ancillaries

Impermeable liner, geotextile, silt trap and a vortex flow control turn a stack of crates into a sealed attenuation system — typically +20–35% on the crate bill.

LEVER 05

Freight & supply route

Where you buy — UK merchant shelf price or manufacturer-direct FOB — sets the markup layer you pay. This is the lever most cost guides never show you.

An attenuation tank provides temporary storage for stormwater and surface water runoff within an impermeable liner and is designed to discharge the stored water slowly over time through a flow control mechanism, thus preventing sudden surges from reaching the sewer system. It serves as the storage component in a two-part stormwater management system, where a soakaway crate lets rainwater infiltrate into the ground, a stormwater attenuation system stores and controls its release. Cost is inherent to the compliance objective; under the Defra 2025 SuDS (Sustainable Drainage Systems) hierarchy, the method by which runoff is managed-whether through reuse, infiltration, a watercourse or ultimately the sewer-is determined before cost becomes a factor. The following breakdown assumes that an underground attenuation system has already been specified for your site.
To illustrate the relative cost scale, a 40m³ car park attenuation scheme with D400 surface load will have a different cost distribution from a 3m³ domestic attenuation tank for a driveway; while both might show similar headline per-m costs, in practice the spread between the five key cost levers is typically between two and three times. Many customers incorrectly assume the project cost is the same as the basic merchant price of a stock crate, only to discover the ancillaries and freight costs as an unexpected increase. Storm Manage breaks down each lever line-by-line at the factory price — unlike a UK reseller adding their markup onto a third-party crate – helping a contractor to offer a fixed-price bid that minimizes mid-build cost variations.
Reference: Defra 2025 National Standards for SuDS (gov.uk)
Attenuation Tank Cost Comparison Graph

Attenuation Tank Cost per m³:
The 3-Material Cost Ladder

The UK market is driven by three technologies and these technologies form a distinct cost ladder, illustrated in the graphs below where the graphs represent the combined 2025/2026 UK supply and installation cost data, against the Environment Agency’s SuDS cost-estimation framework for each. This will allow you to see, at a glance, the market’s view of the relative cost for each technology and compare this against the Government baseline.

Request a Custom Cost Comparison – apply the ladder to your required volume and load class –
System (per m³ storage) Material only Installed Void ratio Design life Best for
Geocellular crate (PP) £70–150 £200–350 94–97% 50+ yr Residential to mid-scale commercial
Precast concrete £180–280 £280–600 ~0% (solid) 100+ yr HGV / deep-burial / extreme load
GRP (fibreglass) £200–350 £300–500 ~0% (solid) 50–80 yr Contaminated runoff, chemical resistance
Large-diameter pipe — £180–320 ~90% 50+ yr Linear routes, road corridors

*Installed costs represent typical UK market ranges (sourced from aquarainwater.com, mixdesigncalc.co.uk and enviroseal.co.uk, 2026), the actual cost per-m depends on the site, the volume required and specification.

*The Environment Agency’s SuDS cost-estimation framework (gov.uk, report SC080039, using a 2008 price base) ranks geocellular below precast concrete per-m and in the same position in the order as the UK market (below precast concrete per-m).

Why is geocellular often the cheapest for most projects?

They are 94-97% void ratio so you excavate far less material for storage. A 12-20kg crate requires no crane whereas a 25-tonne concrete tank will need a low-loader, and they arrive flat-packed to minimise transport. There are occasions when an attenuation tank only really wins on cost, if a 100-year design life or 40-tonne axle load is required. Otherwise, use geocellular and install an appropriately rated tank where required. Be aware, using a cheaper low-spec crate to save on unit cost will result in structural failure – a cheap crate and a cheap project rarely go hand in hand. We publish the complete ladder as we mould our own crates, with no reseller’s retail price to protect. Each product’s cost can be verified against the Environment Agency’s SuDS cost estimation framework and 2026 market data.

APPLICATIONS

For a retail park drainage scheme, covering 250 m, using geocellular for storage for example at a D400 load class compared with the 280-600/m market for a precast concrete tank, typically removes the need for a crane, cuts the excavation in half and brings the installed cost down into the 200-350/m range, creating a 5-figure saving in drainage cost alone. This matches the ordering in the Environment Agency’s SC080039 SuDS cost estimation framework for a commercial setting.

Manufacturer-Direct vs UK Merchant: The FOB-to-Landed Cost Stack

When a UK reseller sells a crate for 120-200/m, it’s already incorporating importer and distributor margins and the retailer’s margin added to a factory cost that is far lower than a UK price. As a UK-based manufacturer producing and exporting crates ex-factory (FOB Shenzhen), we are at the bottom of the ladder, with modular attenuation crates, for example, trading on the open market from around £22-60/m³ FOB ex-works – just a fraction of the cost to buy from a UK merchant.

However, if this cost page were to be honest, it would state: An FOB price is not a landed price. You will need to be able to manage the import process yourself.

But the savings are still on the total landed costs rather than the basic FOB cost when you’ve layered in everything; you get a single, itemized FOB line and we stack the container full to 330m, complete with commodity code and shop drawings, so your forwarder can estimate the rest of the shipping costs with no hidden charges. That’s how we do business.

So, take a 60 m distribution-yard job for US or EU buyer, for example; this typically gets shipped through a UK merchant who layers on an importer, distributor, and a retail margin on top. Our equivalent FOB price (buying the same OE products our own distribution partners would source) is effectively the one price from the OEM plus a shipping and import charge that the buyer can manage on an item-by-item basis. Unlike a reselling intermediary that silently adds the markup, we are completely open with you about where the layer sits. Consequently, the procurement professional who’s comparing like-for-like modular attenuation crates in a project-based volume usually ends up getting a better deal buying direct from the manufacturer.

→ Send for an FOB price line item plus a landed-cost worksheet for the container volume you’re buying. Reference: UK Trade Tariff, commodity code 3925.10.00 (gov.uk)
Attenuation crate loading=
Layer
What it covers
Who carries it
FOB factory price
Moulded crate, ex-works, loaded to container
Manufacturer (us)
Sea freight + insurance
40HQ container, port-to-port
Buyer / forwarder
UK import duty
Commodity code 3925.10.00 (plastic tanks/containers), MFN rate applies
Buyer (EORI required)
Import VAT
20% on the landed value, reclaimable if VAT-registered
Buyer
Clearance & port handling
Customs declaration, THC, haulage to site
Buyer / forwarder

Volume Pricing & MOQ: From 1 m³ to 100,000+ m³

The cost per cubic metre for an attenuation tank is by no means fixed, since the costs are amortised over greater quantities with lower costs associated with production tooling, shipping and handling for every unit produced. We’re able to accommodate requirements from the small end, 1m³ soakaways, up to projects exceeding 100,000m³ and can offer private label and OEM moulding solutions to our distribution partners who wish to offer their own brands.

Scheme scale
Indicative storage
Container logic
Per-m³ trend
Single plot / driveway
1–5 m³
LCL / consolidated
Baseline
Housing / car park
15–60 m³
Part 40HQ
−10–15%
Commercial / development
100–500 m³
1–2 × 40HQ (330 m³ each)
−15–25%
Infrastructure / framework
1,000+ m³
Multi-container programme
Lowest, project-priced

“On a 40HQ we optimise the stack around the crate’s 1000×500×500 mm module and the connector geometry, not just the pallet — that’s how we get to 330 m³ of installed storage in one box. A contractor sizing a scheme in module counts, not tonnes, buys far more accurately.”

— Storm Manage Engineering Team, container loading & mould development
Attenuation tank injection moulding and container loading=
→ Request a container volume-optimised quote based on your project module counts.
Reference: ISO 9001 quality management (iso.org)
If, for instance, we have a residential development with 200 plots and need roughly 300m³ of underground attenuation tanks, this is generally handled in a single 40HQ container of 330m³, sized according to modules and not weight. If you’re too far short of the target number of modules, then you risk having to bring in an additional shipment and a new order midway through the project – something that just isn’t an option in any contractor’s project management plan. We don’t buy in stock from a third party; instead, all our attenuation tank modules are produced in-house on our own 1000T – 2000T injection moulding machines, enabling us to keep adequate buffer stock and to time delivery in line with your installation schedule – an option that’s simply not available with a merchant that resells other suppliers’ crates. Standard lead times are 15-30 days from receipt of your order confirmation. Prices are on an FOB basis out of Shenzhen / Yantian / Shekou, but please note that shipping out of Qingdao or Ningbo is also possible if you prefer.

Total Cost of Ownership: 50-Year Design Life & Maintenance

Buying solely on headline price can cost a fortune over a 20 year design life. Total cost of ownership – which should be the focus for any developer’s finance modelling – depends not on the price of a single module but on the three critical factors of design life, maintenance access, and ensuring the right load class is selected at the initial design phase.

Attenuation Tank Maintenance & Design Life
50+ yr

Design life for the geocellular structure when installed to specification — against a maintenance schedule of periodic silt-trap clearance and inspection-chamber access, not tank replacement.

Storm Manage product design life [manufacturer data]. TCO framing, not a project-specific payback figure — request a whole-life estimate for your scheme.

01. THE TWO TCO LEVERS

Two TCO levers matter most. First, keep silt out of the void with an inlet silt trap and inspection chambers so the stored capacity is maintained throughout the system’s life. Secondly, make sure the load class you’ve specified matches what’s driving on the surface, because under-specifying load for HGV traffic under a car park – the most common false economy – will cost far more in repair than any initial D400 upgrade.

02. MARKET TRANSPARENCY

Unlike a UK merchant reselling one crate brand, we price the concrete attenuation tank line openly beside geocellular, because we mould the crates in-house and hold no shelf price to protect — and the same open ladder applies to any commercial application, from a car-park scheme to a distribution-yard job.

03. GEOCELLULAR VS. CONCRETE

Concrete’s 100-year life span is real, but on many sites a correctly specified, 50-year PP system will represent far less over the period a developer actually plans, and with less ongoing maintenance cost. In many cases on industrial estates (500m site) not to have this is to double the installed cost – failed load-class would blow beyond the cost of the D400. Concrete under-charges installation, crane, low-loader and deeper dig – cost not often recuperated.

04. ACCREDITATION & INTEGRITY

The load-rated PP system – CIRIA C737 accredited and material BS EN 1852 (CE) certified – uses much less plant and equipment, and maintains that storage volume for 50 years. It’s in line with the Environment Agency’s own SC080039 framework – which actually ranks geocellular cheaper than concrete per metre before you factor in freight.

A crate is a crate, the material comes as stated. Unlike a merchant shipping whatever crate is in stock, we set the load class by the traffic that goes over it, not whatever’s in the warehouse, and certified ( CIRIA C737 ) vertical load capacity plus third party compression testing prevents the false economy reaching your maintenance costs.

Attenuation Tank Installation Site

The Hidden Costs: Ancillaries, Freight & What Quotes Leave Out

Line items that break an attenuation budget are never the crate itself. It’s the bits the crate-only quotes fail to price. If you add those in early, the final quote shouldn’t be jumping 25-40%.

On a 40m car-park application, the crates may make up one third of the overall price and the liner, silt trap, geotextile and vortex flow control comprise the other two – forget them at tender and you can be sure the “cheap” quotation will bounce back as a variation. A vortex flow control is required if Building Regulations Approved Document H (gov.uk) requires controlled discharges, or if your water company demands them.

Also budget for the impermeable liner specification: the most common cause of premature failure is underspecified liner overlaps and what started out as a cheap tank suddenly becomes very expensive. Across UK attenuation tanks, the attenuation tank installation cost and the attenuation tank flow control are the two most commonly missing lines on merchant quotations — we itemise both.

Unlike a distributor that sells you crates and leaves you to source the rest, one costed quote from us covers the whole system. Every element on the following list is supplied as a kit with all our systems: all are manufactured in the same factory; geomembrane liner, geotextile separator, inspection chambers, inlets and flow control so ancillaries aren’t a mid project scrabble. We don’t supply just the crates and leave you to find the rest like a distributor – our quotation will cover the entire system.

The Ancillary & Hidden-Cost Checklist

  • Geomembrane liner
    To seal the tank (impermeable)
    £8–15/m²
  • Geotextile fleece
    To protect the liner from puncture
    £2–4/m²
  • Vortex flow control
    Mandated for controlled discharge (simpler orifice plate 80-200; full flow control chamber 1,500-8,000 installed)
    £250–600
  • Silt trap & Catchpit
    Includes inlet connections
    £150–350 each
  • Spoil disposal
    People always forget spoil. A 10m dig equates to 15-18 tonnes and 450-900 to shift it all.
    £30–50 / tonne

PROJECT ENGINEERING CALCULATORS

SYS.01 CALCULATOR

Attenuation Tank Cost Estimator

  • Target System Attenuation Tank
  • Function Core Cost Estimation
OPEN TOOL →
SYS.02 CALCULATOR

FOB-to-Landed Cost Estimator

  • Target System Logistics
  • Function Core FOB-to-Landed
OPEN TOOL →
SYS.03 CALCULATOR

Attenuation Storage Volume Sizer

  • Target System Storage Volume
  • Function Core Capacity Sizing
OPEN TOOL →

Attenuation Tank Cost FAQ

Get Your Attenuation Tank Costed

Email your storage volume (m³), required load class and your delivery port. We’ll send back an FOB price and landed-cost analysis as well as the shop drawings – we don’t offer a “ring us for a quote” solution.

REQUIRED INPUTS
Volume (m³) Load Class Delivery Port
ENGINEERING DELIVERABLES
FOB Price Landed-Cost Analysis Shop Drawings
Request a Costed FOB Quote

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