Where Does the Water Go? Veranda Drainage Connections
homeowner deciding how to connect veranda guttering to drainage
When you install a large glass roof or a bioclimatic pergola, you are effectively creating a new catchment area for rainwater that previously fell directly onto the ground. Managing this runoff is not just a matter of convenience; it is a technical requirement to prevent damp issues or flooding. The decision on where to connect your downpipes depends on your existing ground conditions, local water authority rules, and the proximity of your property's drainage infrastructure.
Connecting to Surface Water Drains
If your property has a dedicated surface water drainage system—common in most post-war builds—this is usually the preferred route. The veranda downpipes are piped directly into a gulley or into the existing underground pipework. This ensures that even during a heavy Pennine downpour, the water is carried away safely into the mains storm drain. It is vital to confirm that you are not accidentally connecting to a foul-water sewer, which is often prohibited by water companies for new surface additions.
Soakaways and Permeable Ground
In many rural or older properties where a surface water main is not available, a soakaway is the standard solution. This involves excavating a pit at least five metres from the house, lining it, and filling it with stone or crates to allow water to percolate slowly back into the soil. The effectiveness of a soakaway depends entirely on your soil type; heavy clay may require a much larger pit than sandy or loamy ground to prevent the system from backing up during a storm.
Combined Drainage Systems
Some older Yorkshire terrace properties use a combined system where both surface and foul water go into the same pipe. Connecting a new roof to these systems often requires specific permission from the water authority, such as Yorkshire Water, and may involve a licensed connection fee. Because these systems are prone to overflowing during peak weather events, authorities are increasingly strict about adding new roof areas to them, so a professional survey is essential to identify the pipe type.
Water Butts and Rainwater Harvesting
For those looking for a more sustainable approach, connecting veranda drainage to a water butt is a popular option. This allows you to store rainwater for garden use, reducing your mains water consumption. However, a water butt alone is rarely sufficient for a large veranda roof; it must have a high-capacity overflow that directs excess water either into a drain or a soakaway, as a single butt can fill in minutes during a heavy storm.
- Connection to existing surface water gulleys
- Installation of a new sub-surface soakaway
- Licensed connection to combined sewers
- Water butt integration with high-flow overflow
Division of Labour: Who Does What?
Standard veranda installation typically includes the structure and the downpipe itself, usually terminating at ground level. The actual connection to the underground drainage or the excavation of a new soakaway is often treated as a separate groundwork task. Some specialist installers offer a 'full wrap' service, while others expect the homeowner to have a groundworker or plumber ready to complete the final link. Clarifying this split before the build starts avoids 'dead-end' pipes sitting on your patio.
Common questions
Can I just let the water run onto the lawn?
While possible on very large, well-draining plots, it is generally discouraged. Concentrated runoff from a roof can quickly saturate the ground, leading to boggy patches or water ingress issues at the house foundation.
How do I know if my drains are combined or separate?
A survey can often determine this by looking at manhole depths and positions, or by performing a dye test. Newer estates almost always have separate systems, while older urban areas often rely on combined pipes.
Do I need a plumber for the drainage connection?
For simple surface water gulleys, an installer or groundworker can often handle it. If you are breaking into a shared main or a combined sewer, a specialist or a WaterSafe-approved plumber is often required for the legal connection.
What size should a veranda soakaway be?
There is no single size; it is calculated based on the roof area and the 'infiltration rate' of your soil, determined by a percolation test. A standard 1 cubic metre crate is a common starting point for medium verandas.
In short
Veranda drainage requires a clear path to a surface drain, soakaway, or combined system, with the connection often requiring coordination between installers and groundworkers.
What to do next
Ask our technical team how we can integrate your veranda drainage with your existing garden infrastructure.
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