Most homeowners scoop out the leaves and stop, and that leaves half the job undone. A flush is the step that proves the system works. Here is how to do it in seven steps, what to watch for at each one, and when not to do it at all.
In This Article
Why the flush matters more than the scoop
Scooping removes the bulk. Flushing tests the result. Running water through a cleaned trough shows you things you cannot see when it is dry: a shallow dip that holds a puddle, a hairline leak at a corner, a downspout that is only half open. It also carries away the fine grit that a scoop leaves behind, which otherwise settles in the outlet.
The whole flush takes only a few minutes per run, and it turns "it looks clean" into "it works".
Seven steps to a proper flush
Before you start, scoop out the debris by hand, wear eye protection and gloves, and set your ladder as you would for any eaves work. Use a garden hose with a spray nozzle. A curved, telescoping wand lets you flush a single-storey run from the ground, which beats holding a hose on a ladder. Keep the wand and the water stream at least 3 metres from any overhead wire, since both can carry current.
- Start at the far end. Begin at the point farthest from the downspout, so the water travels the whole length of the run.
- Use moderate flow. A strong jet splashes muck onto the siding and windows. A steady stream is enough to carry grit.
- Wash the floor of the trough toward the outlet, and watch how the water moves. It should travel at an even pace without stalling.
- Watch the outlet. Water should slip into the downspout in a smooth stream, with no boiling or backing up.
- Check the base. Have a helper, or walk down and look, and confirm a strong flow appears within seconds.
- Look at every joint while water runs. Corners, end caps, seams and downspout connections should stay dry.
- Turn off the water and watch it drain. A thin film is normal. Puddles mean dips.
Repeat for each run and each downspout. A steady flow for a minute or two also gives you a rough test of capacity.
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Reading what the water tells you
| What you see | What it means | What to do |
|---|---|---|
| Water backs up at the outlet | A partial plug in the elbow or pipe | Clear the downspout |
| Only a trickle at the base | A restriction lower down | Flush from below, or check the bottom elbow |
| A puddle mid-run | A sag or a low spot | Re-hang or add a hanger |
| Drips at a seam or corner | A failing seal | Reseal in dry weather |
| Spray from a downspout joint | A separated or split piece | Repair or replace the section |
| Water slows or stalls at ground level | A problem in an underground line | Stop and call a drain specialist |
For sag and slope, the gutter pitch guide explains what to aim for.
When not to flush
- Near or below freezing. Water left in the trough or pipe turns to ice, which creates a slip hazard below and a weight problem above.
- With an underground connection. Use gentle flow and stop if the water backs up. Forcing more in can push a blockage further along or send water toward the house. The underground downspout drainage guide explains how those lines work.
- Near wires. Keep the hose, the ladder and your body away from overhead lines and the service mast.
- Under outdoor water restrictions. A flush needs only a few minutes of flow, but check your municipality's current rules for outdoor water use before you start.
What to do when the flush fails
A failed flush is useful information. A plug means clearing the downspout, using the tools and methods described in our guide to tools for DIY gutter cleaning. A dip means a repair. A leak means resealing. Deal with one problem at a time and repeat the flush after each fix.
Keep a note of the date and how long the water took to reach the base. If next year's flush is noticeably slower, you have an early warning before any overflow shows.
D&D Home Services cleans and flushes eavestroughs across Kitchener, Waterloo, Cambridge and Guelph. See gutter cleaning if you would rather hand the job over. Quotes are free and confirmed in writing before work begins.
Key Takeaways
- Scooping removes debris, but only a flush proves that the trough slopes, seals and drains.
- Work from the far end with moderate flow, watching the outlet, the base, every joint and the drain-down.
- Backing-up water, trickles, puddles, drips and sprays each point to a specific fault.
- Do not flush near freezing, near wires or forcefully into an underground line.
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