Gutters
Where Should Your Downpipes Go? Gullies, Soakaways and Water Butts
Downpipe pouring onto a path or into the wrong drain? Learn where roof rainwater should discharge, from gullies to soakaways and water butts, for Dublin, Lucan and Naas homes.
Most homeowners only think about the bottom of a downpipe when something goes wrong: a puddle that never drains, a damp patch low on a wall, or water splashing across the back door during a November downpour.
Gutters can be in perfect order and still cause trouble if the rainwater has nowhere sensible to go once it reaches the ground. This guide explains where roof water is meant to end up, what Irish Building Regulations guidance says, and the warning signs worth checking from ground level in Dublin, Lucan, Naas and nearby areas.
What the Building Regulations guidance says
Part H of the Building Regulations covers drainage, and the Department of Housing's Technical Guidance Document H (2016) gives the practical guidance. A few points matter for ordinary houses:
- Rainwater pipes should discharge into a drain or gully (paragraph 1.5.2.1). They may discharge onto another gutter or surface, but only if that surface is itself drained.
- Where a downpipe discharges onto a lower roof or paved area, a pipe shoe should be fitted to divert water away from the building.
- A downpipe connecting into a combined system should do so through a trap, so smells from the sewer do not come back up the pipe.
- Surface water drainage should carry roof water to a proper outfall such as a surface water or combined sewer, a sustainable drainage system, a soakaway or a watercourse (paragraph 1.1.3.1).
- Rainwater should not go into a wastewater treatment system such as a septic tank (paragraph 1.1.3.5).
Older houses were built under earlier rules, so not every existing arrangement will match today's guidance. That does not mean it is failing, but it is a useful benchmark when something is clearly not working.
Common discharge arrangements on Dublin-area homes
| Arrangement | Where you often see it | What to look out for |
|---|---|---|
| Downpipe into an open gully | Older semis and terraces across Dublin City and South Dublin | Leaves and silt in the gully, water splashing over the grid, cracked gully surround |
| Downpipe connected directly into an underground drain | Many newer estates in Lucan, Naas and North Dublin | Water backing up and leaking at the joint near ground level |
| Downpipe into a soakaway | Rural and edge-of-town homes, some extensions | Ground staying waterlogged, water pooling near the pipe after rain |
| Downpipe onto a lower roof | Extensions, porches, bay windows | Missing shoe, water hitting the slates or flat roof in one spot, overflowing lower gutter |
| Downpipe running into a water butt | Back gardens | Butt overflowing next to the house wall with no overflow route |
If you are not sure what your home has, look at the base of each downpipe. An open shoe above a grid means a gully; a pipe that disappears straight into the ground usually means a direct connection.
Soakaways: why location matters
A soakaway is a pit filled with rubble or lined with perforated units that lets rainwater soak into the ground. TGD H (paragraph 1.5.8.1) says soakaways should not be built:
- within 5 m of a building or road, or in areas of unstable land;
- where the water table reaches the bottom of the soakaway at any time of year;
- within 5 m of a percolation area or another soakaway;
- where contaminated runoff could pollute groundwater.
Soakaways serving larger areas should follow BRE Digest 365 design guidance. In practice, how well a soakaway works depends on the ground it sits in, and an old soakaway can silt up over the years. If the ground near a downpipe stays saturated for days after rain, or the pipe backs up during a heavy shower, the soakaway may no longer be coping. A soakaway placed tight against the house is worth raising with a drainage specialist, because water concentrated near foundations is exactly what the guidance aims to avoid.
Downpipes onto lower roofs
On extensions and porches it is common for an upper downpipe to empty onto the roof below. That is allowed, but TGD H expects a shoe to throw the water away from the building, and where the upper roof is large (an effective area over 25 m²) a distributor pipe should spread the flow so the lower gutter is not overwhelmed.
Without them, a single jet of water lands on the same tiles or the same patch of flat roof membrane in every storm. Signs of trouble include:
- a lower gutter that overflows only below the downpipe;
- moss, staining or erosion concentrated in one spot;
- a leak inside the extension near where the upper pipe discharges.
Our guide to gutter overflow checks covers the related symptoms.
Misconnections: when rainwater pipes carry the wrong thing
Roof rainwater pipes should carry rainwater only. Dublin City Council's Misconnection Programme explains that a misconnection happens when foul drainage is plumbed into the surface water network, polluting nearby rivers and streams. Renovations and appliances moved to new locations, such as a washing machine in a garden room, are common causes.
The council suggests starting with your rainwater downpipes: if extra pipework is connected into a downpipe, it could indicate a misconnection. South Dublin County Council's Dublin Urban Rivers LIFE FAQs note that homeowners are responsible for correct connections on their own property, and that only rainwater from roofs, paths and driveways should go into the stormwater drain.
If you spot a waste pipe joining a downpipe, Dublin City Council recommends getting advice from a competent plumber. We can tell you if a gutter or downpipe change is part of the fix, but the plumbing itself is plumber's work.
Water butts: useful, if they have an overflow
Uisce Éireann's water conservation tips suggest installing a water butt to collect rainwater from your gutters for the garden or washing the yard. It is a simple way to make use of Irish rainfall.
A few practical points:
- Use a proper downpipe diverter kit so that once the butt is full, water carries on down the pipe to the gully.
- Avoid simply cutting the downpipe short over an open butt. When it fills, the overflow runs straight down the house wall or along the foundation.
- Keep the butt on a stable stand and away from air bricks and door thresholds.
- Clear the diverter filter in autumn, when leaves wash down from the gutters.
Ground-level checklist after heavy rain
You can check all of this safely from the ground. Never climb onto the roof or work from a ladder in wet or windy weather.
- Does each downpipe end in a shoe over a gully, a drain connection, or a drained surface?
- Is water splashing over the gully grid or pooling around it?
- Is there a damp patch, green staining or flaking render low on the wall near a downpipe?
- Does any upper downpipe empty onto a lower roof without a shoe?
- Is extra pipework from a sink, washing machine or toilet joined into a rainwater pipe?
- Does the ground near a soakaway stay waterlogged long after rain stops?
- Does your water butt overflow against the house?
Photograph anything unusual during or just after rain. It helps us see the problem before we visit. Our guide on sending roof leak photos has tips on what to capture.
What we can sort out, and when you need someone else
As roofers, we deal with everything from the gutter down to the shoe: realigning or replacing downpipes, fitting shoes and distributor pipes on lower roofs, re-routing a pipe to a gully, fixing leaking or blocked downpipes and installing diverters for water butts.
Problems below ground, such as a collapsed drain, a silted soakaway or a misconnection, belong with a drainage contractor or plumber. If we find one during a visit, we will tell you plainly rather than guess.
Book a downpipe and gutter check
We repair gutters and downpipes across Dublin City, North Dublin, South Dublin, Lucan, Bray, Wicklow, Naas and nearby areas. If water is pooling, splashing or overflowing at the bottom of your downpipes this winter, send us a photo and we will advise on the next step.
Contact us by WhatsApp, call 083 066 3462, or email hi@perfectroofing.ie.
Need a roofer to take a look?
Send a few photos on WhatsApp, email us, or tap the number to call. We cover Dublin City, North Dublin, South Dublin, Lucan, Bray, Wicklow, Naas, and nearby locations.
