Short definition
A linear trench drain is a long narrow drain — typically 24 to 60 inches — installed at the edge or center of a curbless shower or wet room. Lets the floor slope in a single direction (instead of toward a center point), simplifying tile work and enabling large-format tiles. Standard 2-inch outlet.
What it is
The drain body is a stainless or plastic trough that sits below the finished floor. Water enters through a slot or grate cover and runs down the trough to a single 2-inch PVC outlet that ties into the trap and drain.
The geometry is the point: a linear drain at one wall of a 60-by-36-inch shower lets you slope the entire floor in one direction (1/4 inch per foot toward the drain, per UPC 411). Compare to a center drain in a sloped pan, which requires four-way slopes meeting at the center — every large-format tile gets diamond-cut and the eye sees the seams.
Common 2026 product lines: Schluter-KERDI-LINE, Infinity Drain, ACO ShowerDrain, Quick Drain. Decorative grate options range from utilitarian stainless to tile-in covers that match the surrounding floor.
Why it matters to a homeowner
This is a remodel decision more than a repair vocabulary. If you’re considering a curbless shower or a modern wet-room aesthetic, a linear drain is the standard choice — center drains work but compromise the tile layout.
Cost components:
- Linear drain body: $300 to $1,200.
- Decorative grate cover: $100 to $500 (premium finishes go higher).
- Pro install: $500 to $1,500 incremental over a standard center-drain shower.
Three install fundamentals make or break the result:
- Slope. 1/4 inch per foot toward the drain; the entire shower side falls.
- Drain body height. The drain rim must sit flush with the finished tile face — not too high, not too low. Plan during framing.
- Tanking. The waterproofing membrane (Schluter Kerdi or equivalent) bonds to the drain body’s top flange. If that bond fails, water bypasses the drain entirely and leaks into the framing below.
Common failure modes
- Improper slope. Water pools instead of flowing.
- Sealing membrane not bonded to drain body. Leak below the tile.
- Hair clogs at the slot. Clean monthly.
- Cover slips out of place if not retained. Easy fix; some grates are gravity-only, others lock in.
Common variants
- Linear trench drain (this entry) vs. center shower drain. Different geometry; linear allows single-direction slope.
- Wall-edge linear drain (against a tile wall) vs. center linear drain. Different aesthetic, similar function.
- Tile-in cover (matches surrounding tile) vs. metal grate cover. Aesthetic choice.