Who this guide is for
- Homeowners with water entering the garage
- People preparing to brief a drainage or building professional
- Anyone whose garage floods or seeps in certain weather
- Owners wanting a clear record before an assessment
Where the water enters
Mark exactly where water appears — under the garage door, at a wall-floor junction, up through the slab, around a service entry, or down a wall. The entry point is the most useful thing to pin down.
Describe what you see rather than deciding whether it is surface runoff, groundwater, or drainage.
- Water seeping under the door
- Pooling at a wall-floor junction
- Rising up through the slab
- Running down a wall or at a service entry
Weather and timing
Record whether the water appears during or after heavy rain, snowmelt, or all the time, and how long it takes to drain. A link to rainfall points toward surface drainage; constant damp can suggest groundwater.
Keep a log across several weather events to build the pattern.
Around the garage
Note how the ground and drive slope toward or away from the garage, where downpipes discharge, and whether gullies or channels are blocked. Water arriving from the drive or a downpipe is a common thread.
Record whether neighbouring ground drains toward the garage.
Photographing the intrusion
Photograph the wet area and entry point during or just after the event, the floor extent of the water, and the drive and downpipes outside. Date the images and capture dry states too.
Avoid sealing the entry point before a professional traces where the water comes from.
- Shoot the entry point during the event
- Capture the drive, slope and downpipes
- Avoid sealing before the source is traced
Briefing a professional
Bring your entry-point marks, the weather log, and photos before contacting a drainage or building professional.
Let them trace the path and advise; your record narrows where they look.
Documentation checklist
- 1Mark exactly where water enters the garage
- 2Record whether it follows rain, snowmelt, or is constant
- 3Note how long the water takes to drain
- 4Observe how the drive and ground slope toward the garage
- 5Note where downpipes discharge and whether gullies are blocked
- 6Photograph the entry point during the event and the drive outside
- 7Keep a log across several weather events
- 8Avoid sealing the entry point before the source is traced
Common mistakes to avoid
- Sealing the entry point before a professional traces where water comes from
- Recording 'the garage floods' without pinning the entry point
- Ignoring how the drive and downpipes deliver water to the garage
- Logging one event instead of building a weather pattern
- Assuming groundwater when surface runoff may be the cause, or vice versa
When to involve a professional
- A drainage or building professional should trace and address water entering a garage
- If water rises through the slab or is constant, mention it, as it points to a different path than surface runoff
- Avoid sealing entry points before assessment, as it can hide the source and move the problem
- What is involved varies by site and location, and a professional should confirm the source
Frequently asked questions
Questions readers ask about this topic
Why does water get into my garage?
Garages often sit low or below the drive, so water can arrive as surface runoff, from a downpipe, or as groundwater through the slab. Pinning the entry point and linking it to weather helps a professional trace the source.
Should I just seal where the water comes in?
Sealing the visible entry can hide the source and push water elsewhere without addressing the real path. It is more useful to document where and when it enters and let a professional trace it first.
Why record the weather?
Water that appears with rain points toward surface drainage, while constant damp can suggest groundwater. Logging the weather around each event is one of the most diagnostic things you can capture.
Could my downpipes be causing it?
Downpipes discharging near the garage, or blocked gullies, are common contributors to runoff reaching it. Noting where downpipes discharge and whether channels are blocked is exactly what a drainage professional wants to know.
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