Short definition
A leader or rainwater downpipe is the vertical pipe that carries gutter water from the roof to the ground. The dominant homeowner term in WA is “downspout.” Standard residential sizes are 2×3 inch and 3×4 inch rectangular; the 3×4 size handles PNW rainfall better. Aluminum is the dominant material; copper is decorative; vinyl is cheap but cracks in freezes.
What it is
A downspout connects to the gutter outlet at the top, runs down the exterior of the building, and discharges at ground level — usually through an elbow into a splash block, extension, drywell, rain garden, or cistern. The “rainwater shoe” is the elbow at the bottom that turns the discharge horizontal.
Specifications:
- Profile: Rectangular K-style (2×3 or 3×4 inch) is the residential standard. Round profile is older and persists on craftsman and historic homes.
- Size: 2×3 is adequate for low-rainfall regions; 3×4 is preferred in the PNW because it handles the volume during atmospheric river events without overflowing at the gutter junction.
- Material:
- Aluminum — most common, paintable, lightweight, doesn’t rust. Standard choice.
- Copper — premium, decorative, develops a green patina; common on craftsman restorations. About 4–6x the cost of aluminum.
- Galvanized steel — older, durable but rusts at joints; rare in residential 2026.
- Vinyl — cheap, easy to install, freeze-prone in Eastern WA and inland.
- Spacing: Typically one downspout per ~600 sq ft of roof; place every 35–40 feet of gutter run.
Connection details:
- At the gutter outlet — strap or elbow connection, sealed.
- Brackets every 6–10 feet down the wall — keeps the pipe flat against siding.
- Bottom elbow plus extension — directs water away from the foundation.
Why it matters to a homeowner
Downspout sizing matters more in WA than in drier climates. A 2×3 downspout fed by a gutter draining a steep roof during a 1-inch-per-hour rain event will overflow at the gutter junction — water spills behind the gutter, soaks the fascia, and runs down the siding. Upgrading to 3×4 typically solves this without changing the gutter.
Pre-1960 WA homes often have galvanized steel downspouts that have rusted at the joints. Replacing with aluminum during a gutter refresh is a sensible same-trip job. If you’re keeping the historic look, copper is the period-appropriate match for craftsman, but budget accordingly.
When a contractor quotes a gutter and downspout replacement, the per-linear-foot cost spread comes mostly from material choice. Aluminum-installed in WA in 2026 typically runs $7–$15 per linear foot; copper runs $20–$40. Add downspouts (2–3 per side typical) at $50–$150 each.
Common failure modes
- Clogged at the gutter junction — leaf or needle mat at the drop.
- Loose brackets — bangs against the siding in wind, eventually pulls free.
- Bottom elbow separates — water dumps at the foundation.
- Frozen full of water in deep cold (Spokane / inland) — splits.
- Galvanic corrosion at copper-to-aluminum transitions — rare; happens when materials are mismatched.
Common variants
- Leader (formal / older term) vs. downspout (common US homeowner term) vs. rainwater downpipe (UK / code language).
- Rectangular (2×3, 3×4) vs. round profile.
- Aluminum (standard) vs. copper (premium) vs. vinyl (cheap, freeze-prone) vs. galvanized (legacy).
- Built-in scupper / downspout (commercial) vs. external (residential).