Surface Water and Driveway Drainage in Stockport
Water standing on the drive, or running towards the house instead of away from it. Nearly always the fall, the soakaway or a gully that has been paved over — and it is worth finding out which before anyone lifts a slab.
Get a second opinion before anyone brings a digger.
Where the water is supposed to go
A driveway sheds a surprising volume of water — a modest one sheds a tonne of it in a wet day and tens of thousands of litres over a year, and almost none of that soaks in through block paving on a sand bed. It has to go somewhere, and there are only really three honest destinations: into the ground, into a watercourse, or into a sewer. Building Regulations Part H puts them in exactly that order of preference — the ground comes first, and a sewer is the last resort rather than the default.
What it must not do is simply go into the foul drain, and that is the single most common thing we are asked for. Surface water is meant to soak away, or failing that reach a surface water sewer; it only belongs in a combined sewer where there is no alternative, the sewer has the capacity and United Utilities agree to it. Tipping a drive into a foul run is a large part of why the older combined runs around here surcharge in a downpour and put sewage up somebody's shower tray two streets away. We will not do it as a shortcut. It is also one of the first things a surveyor looks for when the house is sold.
Why drives flood, in roughly the order we find it
- It falls the wrong way. New paving laid flat, or laid to run gently back towards the house. Very common on a drive that has been widened or relaid without anyone checking the levels against the threshold.
- Nothing at the threshold. No channel drain across the garage door or the front step, so everything the drive collects arrives at the one place you least want it.
- The soakaway has silted up. They do not last forever. Fines wash in over the years, the voids fill, and a pit that used to empty in an hour now stands full for two days. The symptom is a drive that copes in summer and not in November.
- There never was a soakaway. More often than people expect, particularly where a drive was laid by whoever paved it rather than by anyone thinking about water. The channel drain runs into a pipe, the pipe runs two metres, and it stops.
- The gully has been paved over. A block-paved drive laid across an existing yard gully, with a slot or a recessed tray left over it that has since filled with grit. The drainage is still down there doing nothing.
- The downpipe discharges onto it. A rainwater pipe cut off at the bottom and left to run across the paving adds the whole roof to the drive's problem.
- The ground will not take it. Stockport has a lot of clay, and clay percolates slowly. A soakaway sized for sand fails on clay no matter how well it is built.
How we work it out
Guessing is what produces the second channel drain that also does not work. Water is easy to follow if you look at it properly.
- 1
Find out where it goes now
Every drive already drains somewhere, even if the answer is "onto next door". Lifting the covers and tracing what is connected to what tells us whether there is a system to fix or nothing there at all.
- 2
Watch it in the wet, or make it wet
Standing water tells you where the low point is. Where it goes when there is a lot of it tells you whether the outlet is undersized, blocked, or absent. This is one job that is genuinely better done in bad weather.
- 3
Test whether the ground will take it
If a soakaway is the answer, the ground has to be able to accept the water. That is a percolation test — dig a trial pit, fill it, time how fast it drops, to the BRE Digest 365 method — and it is what decides the size of the pit rather than a guess. Where it can go is fixed separately: Approved Document H keeps a soakaway at least five metres from a building or a road, which on a front garden is often the constraint that decides the whole design.
- 4
Then, and only then, install
Channel drainage across the threshold, a linear run at the low point, a new or rebuilt soakaway, or correcting the falls. Usually a combination, and usually less than the first quote you were given.
Tell us what the drive does in heavy rain
Where it stands, how long for, and where it goes when it finally moves. That usually narrows it down before anyone comes out.
Common questions
Water runs down the drive towards the house. What can actually be done?
Usually a channel drain across the threshold taking it to an outlet that can cope, rather than relaying the whole drive. Relaying is the answer when the fall is badly wrong over the full length, and it is worth knowing that is the expensive version before anyone quotes it as the only one. Either way the question that decides it is the same: where is the water going to go once it is collected?
Do I need planning permission for a new driveway?
For a front driveway over five square metres facing the road, yes — unless it is laid in a permeable material such as gravel, permeable block paving or porous asphalt, or it drains to a permeable area within your own garden. That rule has been in place since 2008 and it catches a lot of people out after the work is done. Design it in at the quoting stage and it costs almost nothing; retrofit it and it costs a driveway.
Can the driveway just be connected into the existing drain?
Into a surface water drain, yes, if there is one with capacity. Into a foul drain, no. Where the public sewer is a combined one — common on the older runs round here — United Utilities can allow surface water into it, but only where there is no alternative and the sewer has the capacity to take it, and that is their decision rather than ours. What we will not do is tee a new drive into a foul run for convenience: it is a real cause of the surcharging that puts foul water into people's houses further down the run during heavy rain. A lot of older properties have historic connections like this already, which is a different matter from adding one deliberately today.
My soakaway has stopped working. Can it be cleaned out or does it need rebuilding?
Both happen. A ringed or chambered soakaway that has silted can often be jetted and recovered, and that is always worth trying first. A crate soakaway that has clogged in its geotextile generally cannot be, because the blockage is outside the void rather than in it. What cannot be recovered either way is one that was undersized for the ground it sits in, and around Stockport that means clay: clay percolates slowly, and a pit sized as though it were sand was never going to work in a wet winter however clean it is. A percolation test settles which of them you have.
The drive floods in winter but is fine all summer. Why?
Because a soakaway does not fail suddenly — it loses capacity gradually, and the ground around it is already saturated in winter so it has nowhere to empty to. In August the same pit copes with everything you throw at it. It means a summer inspection can genuinely find nothing wrong, and it is one of the few drainage jobs where we would rather come out in the rain.
What to read next
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New runs for an extension, a chamber where there has never been access, surface water drainage that was never put in. Laid to the right falls, camera-tested before it is covered, signed off properly.
Read moreDrain Repairs
When a drain has gone beyond lining, it needs digging — properly, once, and put back the way it was found. Collapsed sections, root damage, failed connections and broken chambers.
Read moreCCTV Drain Surveys
A camera down the drain, full colour footage, and a written report you can actually act on. Usually within the week — and if there is nothing wrong, we will tell you that too.
Read moreSoil Pipe Replacement
Cracked cast iron, a stack that smells, or a joint that has been staining the same patch of wall for years. Most soil pipes want one section putting right rather than the whole run replacing — and you will hear which before anyone quotes.
Read moreWhere we do this
Surface Water Drainage across Stockport and the towns around it. Pick your town for response times, postcodes and the drainage we actually see there.