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Bathroom remodel drawings: what the permit office wants to see

A bathroom is small, but it packs plumbing, electrical, ventilation and waterproofing into a few square feet. That is why a building department looks harder at a bath plan than its size suggests. Here is when you need drawings, which sheets plan reviewers expect, and the clearances they measure.

Updated 2026-10-10. General information, not legal advice. Code sections refer to the 2021 International Residential Code (IRC) as a model. Your city or county adopts its own edition with amendments, so confirm locally.

When a bathroom remodel needs a permit

Most US jurisdictions base residential rules on the IRC. Finish work such as paint, new tile over sound backing, a new vanity in the same spot or a like for like toilet swap is commonly exempt. A permit is usually required once you:

• move or add a drain, vent or water supply line,
• add or move a circuit, outlet or light fixture,
• convert a tub to a walk in shower or build a new shower pan,
• add an exhaust fan or change where it discharges,
• move, open or remove a wall.

The exempt list differs by place. Call the permit counter or read its web page before you design anything; it takes five minutes and decides how much drawing you need.

The sheets a plan reviewer expects

IRC section R106.1 asks for construction documents that show the location, nature and extent of the work in enough detail to show it complies with the code. For a bathroom that usually means a small set rather than a single sketch.

1. Existing floor plan

The room as it stands today: wall positions and thicknesses, the door and its swing, the window, and every fixture. If the house has no old plans, this sheet is drawn from measurements. It lets the reviewer see what changes.

2. Proposed floor plan

The new layout, dimensioned. Show the toilet centerline, the vanity width, the shower or tub size and the door swing. Label new walls and walls being removed. If a wall is removed, the reviewer will ask whether it carries load, and that question needs a licensed engineer or architect, not a drafter.

3. Plumbing plan or notes

Which fixtures move, where new drains run and how they are vented. Many departments accept notes on the floor plan for a simple bath. A moved toilet or a new shower drain usually needs to be drawn.

4. Electrical and ventilation plan

Receptacles, switches, lights, the exhaust fan and where it discharges. Bathroom receptacles need ground fault protection under the National Electrical Code as adopted locally, so mark them. The IRC requires bathrooms to be ventilated, either by a window of a minimum size or by mechanical exhaust; IRC section M1505.4.4 sets the minimum fan rate at 50 cfm intermittent or 20 cfm continuous. Note the fan rating on the plan and show that it vents to the outside, not into the attic.

5. Interior elevations

Not every department asks for them, but they help: the shower wall with valve height and niche, the vanity wall with mirror and light, and the wall tile extent. They also help your tile setter price the job.

Clearances the reviewer will measure

The fixture clearances in IRC section R307.1 and its figure are the numbers most often checked on a bath plan. In the 2021 model code they include:

We read the R307.1 clearances on the UpCodes copy of the New Jersey adopted IRC 2021 on 2026-10-10. That same page shows why local editions matter: New Jersey's adopted R305.1 sets a ceiling height of 7 feet 8 inches, not the model 7 feet. Always check the edition your department enforces.

Draw these clearances as dimensions, not as a note saying "per code". A reviewer can check a dimension in seconds; a note forces them to measure your drawing with a scale.

Shower and waterproofing notes

A tiled shower is where most bathroom failures start, so departments often want a note on the waterproofing method: a liner and mortar bed, or a sheet or liquid membrane, with the product named. Note the glass type if there is a glass door or panel, since glazing next to a tub or shower is a hazardous location that needs safety glass. Show the shower valve as pressure balance or thermostatic, which the plumbing code requires for shower controls.

Common reasons a bath plan comes back

• The toilet is 13 or 14 inches from a wall or vanity because the vanity grew during design.
• The door swings into the toilet or the vanity, so the clear space in front of a fixture is blocked.
• The exhaust fan has no rating or no discharge route shown.
• A wall is removed with no note on whether it bears load.
• The existing plan is missing, so the reviewer cannot tell what is new.

How detailed should the drawings be?

Scaled and dimensioned, but not architectural art. A clean set at 1/2 inch or 1/4 inch per foot, on 11x17 sheets, with the existing plan, proposed plan, electrical and ventilation notes and one or two elevations covers most residential bathroom permits. A set like this also gives the plumber, electrician and tile setter the same plan to price from, which is often worth more than the permit itself. Our bathroom material takeoff example shows how the same plan becomes a list of quantities.

Where drafting stops

Drawings record and describe the work. They do not certify structure, and they do not guarantee approval. Structural changes, such as removing a bearing wall or cutting a joist for a new drain, need a licensed engineer or architect. Some departments also require a licensed professional to stamp any plan; ask before you order.

Checklist before you submit

1. Confirm with your department which work needs a permit and which code edition it enforces.
2. Measure the room, ceiling height, door, window and every fixture position. Our guide on how to measure a room for drawings covers the routine.
3. Draw existing and proposed plans, with the toilet, lavatory and shower clearances dimensioned.
4. Add electrical and ventilation notes, with the fan rating and discharge.
5. Add the waterproofing method, safety glass and shower valve type as notes.

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