Where the Downspout Lands: Green Splash Streaks on Lower Siding in Delta & Surrey
It is Saturday, October 24, 2026, and the fall rains are settling in across Delta and Surrey. On a lot of north walls the new mark is not a full green film. It is a pair of dark streaks, starting where the downspout dumps and running up the lower siding, the corner trim, and the edge of the walk.
It is Saturday, October 24, 2026, and the fall rains are settling in across Delta and Surrey. On a lot of north walls the new mark is not a full green film. It is a pair of dark streaks, starting where the downspout dumps and running up the lower siding, the corner trim, and the edge of the walk.
Halloween is next Saturday, October 31. Daylight saving time ends on Sunday, November 1, so sunset shows up an hour earlier by the clock. Pumpkins, pots, and the first holiday stakes are about to sit in that wet corner. Deal with the splash line now, while the film is still a streak and you can still reach the pad.
Our post on fall soft washing for green siding is the whole shaded wall, from earlier in the fall. The fascia, eaves, and soffit piece is the band under the roof. The patio and walkway guide is the path you walk on. This one stays on the grade-level splash those posts leave at the bottom of the wall: why the streaks show up this week, why the siding wants a soft wash rather than a high-pressure blast, and why the concrete under the spout is a different surface on the same visit.
Why the splash line shows up as the rains settle in
A gutter can be doing its job and still paint the wall. Water leaves the roof, runs the trough, and comes out the spout. In late October a Pacific front puts a lot more water through the same pipe, and it lands on the same small patch every storm.
On Lower Mainland houses that landing spot has a few habits:
- It stays in shade. North walls under maples and cedars in Delta and Surrey barely dry between fronts. An open Ladner or Tsawwassen corner can do it too, once the bed stays wet.
- It sits against the foundation. A short extension, or one buried in wet leaves, dumps at the siding instead of out on the lawn.
- It feeds organic film. Algae and mildew like the strip that never quite dries. The streak is that growth on the surface. It is not, by itself, rot.
- It marks the pad. The same water leaves a dark fan on concrete, and leaf tannin turns that fan brown and slick.
Leaving the streak through November makes the line darker. A wash treats the film that is there. It does not guarantee an old shadow lifts, and it does not move the spout.
Streaks on the lower wall are not a whole green elevation
After a shower you are often looking at two patterns on the same house.
- A pair of vertical lines. They start at the splash block or the end of the extension and fade around knee or waist height. That is the spout. The rest of the wall can still look ordinary.
- An even green haze. The whole north elevation has gone dull. That is the shaded-wall film in the fall siding post, and it is a wider soft-wash scope than this corner.
- A sheet off the gutter lip. Water that never enters the trough wets the fascia first, then the wall under it. That pattern belongs with the eave band, and it usually means the gutter is packed. Washing the streaks does not open the trough.
If the lip is spilling, or the spout gurgles, clear the gutter before you wash the wall. Clean gutters at least twice a year, once in late fall after the leaves drop and again in early spring. Houses under overhanging trees often need more.
Gutter cleaning includes debris removal, downspout flushing, and a look at brackets, sag, and slope, plus a ground cleanup and before-and-after photos. We are fully insured. A cleaning does not reattach a spout that has pulled away, replace a split elbow, or lengthen an extension. Our post on gutters that still overflow after a cleaning covers a trough that looks clear while the water still will not leave.
Soft wash the siding, and keep high pressure on the pad
The siding, the corner trim, and any painted wood in the splash want a soft wash. That is low pressure, a cleaner aimed at organic growth, and a controlled rinse. High pressure can knock some of the colour off. It can also drive water behind vinyl laps, fuzz wood grain, and lift paint. The growth is in the film. A tight nozzle often smears it higher up the wall, so a short streak becomes a longer one.
The bare concrete pad, a plain splash block, and the walk that takes the fan can take pressure washing. That is the hardscape job: algae, tannin, and grit on concrete. Painted steps, a wood porch, and composite in the same corner should not get that blast. If the path beyond the pad is slick, the patio and walkway post is the wider piece. This visit can include the pad under the spout without turning into a whole-yard wash.
Both methods are booked from that pressure washing page, which lists driveways, walkways, decks, patios, house siding, and fences. Name the streaks and the pad. The tool has to match the surface.
- Rinse the bed. Plants at the spout need dirty water moved through, not left in the mulch.
- Leave the glass alone. A sidelight beside the splash is a window wash, not a pressure tip. A wash does not repair a failed seal.
- Stay on the ground. You can see this streak from the grass. Skip a ladder in the rain. If a line is down or sparking, stay back and call BC Hydro.
A soft wash does not guarantee every stain lifts, especially where tannin has sat in the paint. It treats the film without treating the cladding like a driveway.
What you can see without moving a ladder
Walk the corner during the next shower, or right after it. A photo of the spout, the lower streaks, and the pad is enough for a quote. Most quotes are provided within 24 hours.
- The landing. Water should leave the extension and travel away from the foundation. A fan that wets the wall is the splash line.
- The streaks. Green, grey, or black lines on the lower courses are organic film. They are not, by themselves, rot.
- The pad. A dark slick patch is the concrete half of the same problem, and it is where people stand next Saturday.
- The hardware. A gurgling spout, a popped elbow, or an extension buried in leaves is a gutter note. Flushing is part of gutter cleaning. Replacing a broken section is not.
- The decor. If a pumpkin or a stake is about to cover the streak, wash first. The after-Halloween cleanup post is for the mess once it is already on the concrete.
A simple order before the wettest weeks
The table is a sequence for this corner, not a promise that every house needs every step. If the gutter is already spilling over the lip, that comes first.
| What you are looking at | Which wash | Why it matters this week |
|---|---|---|
| Gutter lip spilling, or a spout that gurgles | Gutter cleaning first, including a downspout flush | A wall wash does not open a packed elbow, and a cleaning does not replace a split spout. |
| Green or black streaks on lower vinyl, wood, or painted siding | Soft wash | High pressure can drive water into laps. A wash does not guarantee an old shadow lifts. |
| Bare concrete pad or walkway where the spout dumps | Pressure wash | Wash the pad after the spout is moving water, or the next front repaints it. |
| Painted steps, a wood porch, or the door surround | Soft wash, not a blast | The same careful rinse as the siding. A rental tip on full blast is how paint lifts and grain fuzzes. |
| An even green film across the whole north wall | A wider soft-wash scope, if you want it | That is the full elevation, not the splash line. This corner can be quoted on its own. |
| Pumpkins, pots, or stakes about to cover the corner | Wash, then let the surfaces dry, then set decor | Decor on wet film hides the streak and gives sugar and soil a place to sit through the next rain. |
Point the extension you already have away from the wall before anyone washes. A wash is not a drainage repair. A broken elbow belongs with a qualified installer.
How this corner fits Halloween week and the lights
Halloween night is October 31. A slick pad is a footing problem before it is a curb-appeal one. Pressure washing the concrete after loose leaves are off it makes the landing easier to stand on. It does not guarantee the next storm stays off the surface, and it does not fix a heaved slab or a broken step.
Say so on the quote if guests will stand there. A house starts with residential exterior cleaning. A shared townhouse spout, where one elbow wets the next unit, goes through our commercial and strata service. We are fully licensed and insured for commercial work. On a common wall, check the strata rules before anyone washes.
Christmas light installation uses drill-less clips on fascia, eaves, and gutters. Installs run from October 1, crews are normally fully booked by the middle of November, and bookings close December 10, 2026. A stake in a soggy bed at this corner is easier before the display is up. The free 48-hour service guarantee covers a failed light, not a streak on the siding. Details are on the Christmas lighting page.
Quick answers
Will the next rain rinse these streaks off?
No. More rain is what feeds them. A Pacific front adds volume at the same landing. It does not lift algae or mildew off siding.
Can I pressure wash the streaks off the vinyl this weekend?
Leave the high-pressure tip off the wall. Soft washing is the method for siding and painted trim. Pressure washing belongs on the bare concrete pad and the walk. A blast can force water behind the cladding. A wash does not guarantee every mark leaves.
The gutters were cleaned in September. Why is the wall streaking now?
Late October puts more water through the spout, and many trees are still dropping. If the spout gurgles or the lip spills, the trough may need another look. Clean gutters at least twice a year.
Should the pumpkins go out before the wash?
Wash the pad and the streaks before the decor sits on them if you can. Sugar that rots into a wet week is a harder stain. A wash now does not guarantee the landing stays clean through Halloween night.
Does a soft wash mean the streaks will not come back?
No. If the spout still lands on the wall, the next fronts feed the same strip. Move the water off the foundation where you can, flush a clogged spout, then wash. We clean the film. We do not rebuild the drainage, and a cleaning does not guarantee the line stays gone.
Clear the splash line before the dark weeks settle in
Late October in Delta and Surrey is a short gap. The rains are here, the evenings get shorter on November 1, and the corner by the spout is about to hold pumpkins and then holiday decor. A streak you can still see from the grass is easier to treat than a band that sits wet until spring.
If the lower siding under a downspout has gone green or black, the pad is slick, or the extension is dumping at the foundation, tell us what you see and where the house is. We will quote the soft wash on those streaks and the pressure wash on the concrete, and the gutter flush if the spout is not moving water. You can also call 778-652-5906.