Exact bathroom heights: WC rough-in at 30.5 cm and sink at 85 cm. Clearances, steps, and pro tips to avoid callbacks and speed installs.
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Most clients want a simple rule: set the toilet rough-in at 30.5 cm (12 in) and the sink rim at 85 cm (33.5 in). Many even search for “Medidas exactas para un baño perfecto! WC a 30.5cm y lavabo a 85cm.” Here’s the clear guide. We explain what those numbers mean, why they work, and how to hit them every time. Use these steps to prevent rework, pass inspections, and keep customers happy.
For a standard bathroom, center the toilet drain at 30.5 cm (12 in) from the finished wall. Set the sink rim at 85 cm (33.5 in) above the finished floor. Keep at least 38 cm (15 in) from the toilet centerline to each side wall and 61–76 cm (24–30 in) of clear space in front.
On most jobs, errors start at framing. You measure from studs, not the finished wall. Then tile adds 10 mm, and the toilet won’t fit. Don’t make that mistake.
Pro tip: Mark a “finish line” on the slab or subfloor. Write down exact layers and thicknesses. It takes 5 minutes and can save hours.
The standard rough-in is 30.5 cm (12 in) from the finished wall to the drain center. Most modern toilets are built for this. Some models use 25 cm (10 in) or 35.5 cm (14 in), but 12 in is the default.
Why it works:
How to hit it:
Clearances for code and comfort:
If the client asks for the “exact” setup, keep it simple and consistent:
These numbers fit most standard fixtures and save you from rework.
The 85 cm (33.5 in) sink height lands well for most adults. It reduces back strain and lines up with common vanities.
Choose the style:
Plumbing layout that works:
Accessibility note: For ADA-style installs, keep the sink rim at 34 in (864 mm) max, and protect knees under the basin. Many contractors build two heights in multi-bath homes.
Clearances matter more than perfect numbers. Tight fits cause daily pain and complaints.
If you’re also looking to streamline professional proposals, our guide on creating professional proposals pairs well with this planning stage. It helps you confirm scope and avoid layout disputes. For contractors dealing with billing, look for invoice templates that save time after punch-out.
Follow these steps to hit 30.5 cm and 85 cm on the first try. Plan 2–3 hours for layout and rough checks, and 1–2 hours for fixture set.
Confirm Finishes
Mark the WC Rough-In
Set the Flange
Place the Toilet
Mark the Sink Height
Rough the Plumbing
Mount and Connect
A clean handoff reduces callbacks. Take photos of measurements with a tape visible. Note heights on the punch list. Many contractors capture site notes and voice memos, then build proposals fast using tools like Donizo. You can record details on-site, send a branded proposal, get an e-signature, and convert to invoice when the client approves.
No. It’s the most common. Some bowls use 25 cm (10 in) or 35.5 cm (14 in). Always check the spec sheet. If space is tight, a 10 in model can save a job.
Aim for a small gap: 6–10 mm (1/4–3/8 in) between tank and wall. If it touches, you risk cracks and noise. If the gap is larger than 20 mm, the rough-in is likely off.
Standard is 85 cm (33.5 in). For shorter users, drop to 81–83 cm. For taller users, raise to 88–90 cm. In shared homes, 85 cm is a solid middle ground.
Set the mirror bottom at 97–102 cm (38–40 in) above the floor. Place the faucet spout 20–25 cm (8–10 in) above the sink rim. This prevents splash and keeps the mirror usable for most heights.
If tile adds thickness and you measured from studs, your WC may sit too close. Use an offset flange (moves the center 19–25 mm), or swap to a 10 in rough-in bowl. Next time, plan from the finished wall.
Hitting 30.5 cm for the toilet rough-in and 85 cm for the sink rim delivers a clean, comfortable bathroom. Plan from finished surfaces, protect clearances, and follow the steps above. Next moves: 1) Confirm all finish thicknesses, 2) Mark heights on walls before rough, 3) Photo-document final dimensions. To communicate scope fast and get approval, many pros use platforms such as Donizo to capture details, send proposals, and collect e-signatures. Lock in these measurements, and your installs will go smoother on every job.
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