Where we work
We are drainage engineers and civil engineering designers working across Hertfordshire and Bedfordshire. We have delivered 17 projects here — drainage strategies, SuDS reports, flood risk assessments and highway design, prepared for planning and taken through to approval.
You do not need a consultant down the road from your site. This is desk work built on survey data, ground testing and the local authority’s own standards. What matters is that whoever does it knows what Hertfordshire County Council, Central Bedfordshire and Milton Keynes asks for, and what the ground in Hertfordshire and Bedfordshire will actually do.
Our projects in Hertfordshire and Bedfordshire, in red, against the rest of England. One dot per project, placed within its postcode area rather than at the exact site. Zoom out for the full picture, or ctrl and scroll to zoom.
Civil engineering design in Hertfordshire and Bedfordshire
- Drainage design in Hertfordshire and Bedfordshire — surface water and foul drainage strategies, attenuation, SuDS and outfall design, sized for your site and your discharge rate.
- SuDS design — sustainable drainage design and the SuDS statement your planning authority expects, with the drainage hierarchy worked through in order.
- Flood risk assessments — site-specific flood risk assessments for sites in Flood Zones 2 and 3, and for sites over a hectare in Zone 1.
- Highway design — access, visibility splays, turning heads and adoptable road design, including Section 38 and Section 278 agreements.
- Percolation testing — BRE 365 soakaway testing across Hertfordshire and Bedfordshire, arranged through PT (West Midlands) Ltd so the design and the testing come from one place.
Ground conditions in Hertfordshire and Bedfordshire
The oldest ground at surface here is Gault Clay and Chalk, but the higher ground is largely covered by glacial boulder clay — a stiff brown clay full of chalk fragments. The chalk itself can accept water, and bored soakaways taking water below the solution features are sometimes used, but they engage the Environment Agency because of the aquifer beneath. Solution pipes in the chalk are a genuine hazard for a shallow soakaway.
None of that tells us what is under your plot, and no report should pretend otherwise. It tells us what to expect, what to test for, and whether to plan for infiltration or for attenuation and a restricted discharge. A percolation test to BRE 365 settles it, and it is cheaper to do that before the design than to redesign afterwards.
Source: Hertfordshire Geological Society. Requirements and ground conditions both change — we check them at the start of every job.
The drainage hierarchy
- 1InfiltrationSoakaway or infiltration basin, if the ground takes it
- 2WatercourseDischarge to a surface water body, usually rate-restricted
- 3Surface water sewerWhere a public surface water sewer exists and has capacity
- 4Combined sewerLast resort, and increasingly refused outright
Every scheme has to work down this list in order, and show why each option above the chosen one was ruled out. The ground is what decides whether you get to stop at step one.
Hertfordshire and Bedfordshire at a glance
- Lead local flood authority
- Hertfordshire County Council, Central Bedfordshire and Milton Keynes
- Postcode areas
- HP, LU, MK, SG
- Projects delivered here
- 17
- Statutory consultee
- Yes, on surface water for major development
- Percolation testing
- BRE 365, via PT (West Midlands) Ltd
- Case studies
- 6
What Hertfordshire County Council expects
Hertfordshire publishes a checklist setting out what is required at each stage of the development management process, rather than one undifferentiated list. That makes it unusually clear what you can leave until later — see what is needed at each planning stage.
The county council has been a statutory consultee on surface water for major development since 15 April 2015, and publishes SuDS design guidance alongside its local flood risk management strategy. Central Bedfordshire, Bedford and Milton Keynes are separate lead local flood authorities.
Source: Hertfordshire County Council. Requirements and ground conditions both change — we check them at the start of every job.
SuDS design in Hertfordshire and Bedfordshire
Drainage is the bulk of what we do, but in Hertfordshire and Bedfordshire a large share of it comes with SuDS design attached — because boulder clay over the higher ground, and solution features in the chalk beneath, push most schemes towards attenuation.
Where infiltration is out, the scheme becomes attenuation: storage sized for the critical storm, a flow control set to the discharge rate Hertfordshire County Council will allow, and treatment stages appropriate to what the water has run over. Done well that is basins, swales and permeable surfacing doing visible work in Hertfordshire and Bedfordshire, rather than a tank buried under a car park doing the minimum.
We do this as part of the same job, so the SuDS design and the drainage strategy agree with each other rather than being written by two firms who never spoke. More on SuDS design.
What you need, and when
The work is not one document handed in once. It arrives in stages, and sending the wrong level of detail at the wrong stage is one of the commonest reasons an application stalls with Hertfordshire County Council.
- Outline application. A strategy showing the principle: where the water goes, roughly what it will take, and that the site can be drained at all. Detailed calculations are not expected yet, but a strategy that ignores the discharge hierarchy will be questioned.
- Full application. The full surface water and foul scheme with calculations, layout, attenuation volumes and the discharge rate you are asking for, evidenced.
- Reserved matters. The detail that was reserved at outline, now built out against the approved strategy — and it has to match it.
- Discharge of conditions. The final submission against the wording of the condition itself, with the maintenance and management arrangements Hertfordshire County Council asks for. This is the stage most people reach us at, often with a condition already imposed.
Where the work lands
- OutlineDrainage strategy: the principle, not the detail
- FullFull scheme, with calculations and discharge rate
- Reserved mattersThe detail, matching the approved strategy
- DischargeSubmission against the condition wording itself
Most people reach us at the last step, with a condition already imposed. That is fine — it is just cheaper to have got the strategy right at the first.
Typical conditions we discharge in Hertfordshire and Bedfordshire
Exact wording varies between officers and between applications, but conditions on sites here almost always fall into three shapes:
- Surface water drainage. “No development shall commence until a detailed surface water drainage scheme, based on sustainable drainage principles and an assessment of the hydrological and hydrogeological context of the development, has been submitted to and approved in writing by the Local Planning Authority.” This is the one that needs the percolation results and the attenuation calculations.
- Foul drainage. A scheme for foul water disposal, agreed before occupation — straightforward on a mains connection, considerably less so on a package treatment plant or where the sewer is at capacity.
- Management and maintenance. A plan setting out who maintains the drainage for the lifetime of the development, and how. Often overlooked, and a common reason a discharge application comes back.
If you have a condition in front of you, send us the wording. We will tell you what it actually requires, before you commit to anything. There is a fuller guide to drainage planning conditions if you want to read up first.
Our work in Hertfordshire and Bedfordshire
Past project locations here include Milton Keynes, Buckinghamshire, Cambridgeshire, Bedford, Deanshanger Road, Heelands and Leighton Buzzard.
- A single dwelling in Chesham
- An industrial development in Luton
- A garden centre in Hemel Hempstead, Hertfordshire
- A single dwelling in Dunstable
- 2 dwellings in Bucks
- A single dwelling in Over, Cambridgeshire
Questions we get asked in Hertfordshire and Bedfordshire
Do you need to be local to do this work?
No. It is done from survey data, ground investigation and Hertfordshire County Council’s own standards, none of which require us to be nearby. Being the right distance from your site has never discharged a condition; knowing what the authority wants has.
Who is the lead local flood authority for my site?
Hertfordshire County Council, Central Bedfordshire and Milton Keynes. They are a statutory consultee on surface water drainage for major development, and they set the local standards and the discharge rate your scheme is judged against.
Can I use a soakaway?
Often not, here — see the ground conditions above. That is a normal outcome, not a failure. Where infiltration is not viable we design attenuation with a restricted discharge, which is what most schemes in Hertfordshire and Bedfordshire end up with.
What counts as a SuDS scheme?
Not just a tank in the ground. Hertfordshire County Council expects the drainage hierarchy worked through in order, with water quality and amenity considered, and a maintenance plan naming who looks after it for the lifetime of the development.
What holds a drainage scheme up?
Usually the ground testing, and where one is needed, the response time from Hertfordshire County Council or the water company — not the design itself. Getting the testing booked early is the single biggest thing you can do to keep a scheme moving.
I already have a planning condition. Can you deal with it?
Yes, and it is most of what we do. Send us the condition wording and the site address and we will tell you what is needed to discharge it.
Get a quote for your Hertfordshire and Bedfordshire site
Send us the site address and the condition wording, or the planning reference, and we will tell you exactly what is needed. If you do not need us, we will say so.