Who this guide is for
- Homeowners planning new gutters or noticing water pooling at downpipes
- People wanting roof water led away from the building
- Anyone preparing to brief a drainage or gutter professional
- Owners scoping discharge before committing to a system
Routing is separate from gutter sizing
Gutter and downpipe sizing handles how much water the system carries; routing handles where that water ends up. A perfectly sized system can still cause problems if it discharges against a wall or onto a path.
Keeping these as distinct questions helps you plan and brief a professional clearly.
Where the water should go
The aim is to discharge water where it is led away from the building and managed — to a drainage system, a soakaway-type arrangement, or a graded route away from the foundation, depending on the site. Discharging against the wall base is what you are trying to avoid.
You are planning the intent; how and where it actually connects is a drainage professional's decision.
- Away from the wall and foundation
- Into a managed drainage route where available
- Onto ground graded to carry water away
- Not onto paths that pond or ice over
What the discharge can affect
Poorly routed downpipe water can contribute to damp walls, basement moisture, eroded beds, and icy paths. Noting where current downpipes discharge and any problems there helps a professional plan a better route.
Record where water currently pools or stains near downpipe outlets.
Coordinating with the wider site
Downpipe routing connects to gutters above and foundation and yard drainage below, so it should be planned as part of the whole water path, not in isolation. The right route depends on what drainage the site already has.
Capturing the site's existing drainage helps a professional join it up.
Briefing a professional
Bring notes on where downpipes currently discharge, any pooling or damp there, and the site's drainage before contacting a drainage or gutter professional.
Let them design the route and any connections; your planning keeps the discharge in focus.
Planning checklist
- 1Separate routing of the discharge from gutter and downpipe sizing
- 2Note where each downpipe currently discharges
- 3Identify any pooling, damp or erosion near outlets
- 4Aim to lead water away from the wall and foundation
- 5Consider where the site can manage discharged water
- 6Avoid discharge onto paths that pond or ice over
- 7Note the site's existing drainage to coordinate with
- 8Prepare questions on routing and connections for a professional
Common mistakes to avoid
- Treating downpipe routing as solved once the gutter is sized
- Discharging water right at the base of a wall
- Ignoring pooling or damp near existing downpipe outlets
- Routing discharge onto paths where it ponds or freezes
- Planning the downpipe in isolation from the wider drainage path
When to involve a professional
- A drainage or gutter professional should design where downpipes discharge and any connection to drains or ground systems
- Connecting to drainage systems can be regulated and site-specific, so leave it to a qualified professional
- Where discharge affects foundations or neighbours, professional input is especially important
- How roof water should be routed varies by site, drainage and location, and a professional should confirm the approach
Frequently asked questions
Questions readers ask about this topic
Isn't downpipe routing just part of the gutter system?
Sizing the gutter and downpipe handles how much water the system carries, but routing handles where it ends up, which is a separate question. A well-sized system can still cause problems if it discharges against a wall.
Where should a downpipe discharge?
The aim is to lead water away from the wall and foundation into a managed route or onto ground graded to carry it off, depending on the site. The specifics, including any drainage connection, are a drainage professional's decision.
What problems come from poor discharge?
Water dumped at the wall base can contribute to damp walls, basement moisture, eroded beds and icy paths. Noting where current downpipes discharge and any problems there helps a professional plan a better route.
Can I connect a downpipe to a drain myself?
Connecting to drains or ground systems can be regulated and site-specific, so it is for a qualified drainage professional. Plan where you want water to go and let them design the connection.
Keep reading