standard-shower-dimensions
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Standard shower dimensions are not set by one national rule. The sources we opened give code minimums from two state plumbing rules and a federal accessibility standard, and each one measures a different thing at a different point. This guide puts those figures side by side, explains how to measure your own shower the way the codes do, and marks which points rest on one source or on none. Read the numbers as code text. They do not describe what most homes have.
Quick answer
- No single national standard for residential shower size appears in the sources we opened.
- Minnesota and Washington both set a minimum of 900 square inches of finished interior, with room for a 30 inch circle.
- The 2010 ADA Standards give 30 by 60 inches for a standard roll-in shower and 36 by 36 inches for a transfer shower. These are accessibility sizes, not general minimums.
- Measure the finished interior, not the framing, and check the height each code names.
- Codes differ by state and by local adoption. Check the plumbing code that applies where you live.
How we chose
We limited this post to official text we opened on 2026-10-27. The three sources are the 2010 ADA Standards for Accessible Design, section 608 (Shower Compartments); Minnesota Rules 4715.1380, subpart 4; and Washington’s state plumbing code section 408.6, as published in WSR 21-01-125 with an effective date of January 15, 2021. Every figure in the table below must appear in one of these texts. Retail product pages were not used for any figure, and no blog or forum page was used as a source.
Where only one source states a point, the table and the text say so. Where Minnesota and Washington agree, we say that too, because they are two separate state rules and not one national standard. Where a point is not covered at all, the table says “Not stated” rather than filling the cell with a typical size from memory.
The figures the sources state
The table lists each figure with the source that gives it. “Not stated” means none of the three sources covers that point.
| Point | Figure in the source | Source |
|---|---|---|
| Minimum finished interior area | 900 square inches | Minnesota 4715.1380 and Washington 408.6 (two sources) |
| Circle the shower must encompass | 30 inch circle | Minnesota 4715.1380 and Washington 408.6 (two sources) |
| Minimum finished interior dimension (Minnesota) | 30 inches | Minnesota 4715.1380 (one source) |
| Height the dimensions must hold (Washington) | 70 inches above the drain outlet | Washington 408.6 (one source) |
| Standard roll-in shower (accessible) | 30 by 60 inches, clear inside | ADA 2010 Standards 608.2.2 (one source) |
| Transfer shower (accessible) | 36 by 36 inches, clear inside | ADA 2010 Standards 608.2.1 (one source) |
| Typical size of a shower in a home | Not stated | None of the three sources |
The accessible sizes in the ADA text
The 2010 ADA Standards for Accessible Design describe shower compartment sizes in section 608. The Standards are described in the text as “enforceable accessibility standards” under Titles II and III of the Americans with Disabilities Act. Section 608.2.2 says that “Standard roll-in type shower compartments shall be 30 inches (760 mm) wide minimum by 60 inches (1525 mm) deep minimum clear inside dimensions.” Section 608.2.1 gives the transfer type as 36 inches by 36 inches, clear inside, measured at the center points of opposing sides.
These are the sizes to use when the accessible rules apply. The sources do not say whether these sizes apply to a private home that is not covered by the ADA, so do not treat them as the general standard for every bathroom.
The Minnesota rule
Minnesota Rules 4715.1380, subpart 4, says that “No shower stall or receptor shall have a finished interior dimension which is less than 30 inches.” It also says each compartment must be “capable of completely encompassing a 30-inch circle measured at the height of the shower control handles” when the door or curtain is closed. The same subpart requires “a horizontal cross sectional area of not less than 900 square inches.” The rule then adds that “The 30-inch requirement shall not apply to a bathtub used as a shower or to showers installed in remodeling.”
That last sentence matters for anyone planning a remodel. Under the Minnesota text, a shower installed during a remodel is outside the 30 inch width rule. The 900 square inch area and the 30 inch circle are written in the same subpart without that remodel exception, so read the exception closely before you rely on it.
The Washington rule
Washington’s state plumbing code, section 408.6, applies to shower compartments “regardless of shape.” The text in WSR 21-01-125 says a shower must have “a minimum finished interior of nine hundred (900) square inches” and must be “capable of encompassing a thirty (30) inch (762 mm) circle.” The section says the minimum area and dimensions “shall be measured at a height equal to the top of the threshold and at a point tangent to its centerline.” They must also be “maintained to a point of not less than seventy (70) inches” above the shower drain outlet.
The section lists what may stick into that space: fixture valves, the shower head, soap dishes, shelves, and safety grab bars or rails. A fold-down seat in an accessible shower stall is allowed to protrude into the circle. The Washington text lists two exceptions: showers designed to comply with ICC/ANSI A117.1, and a shower receptor with overall dimensions of at least 30 inches wide and 60 inches long. The same 408.6 text appeared in the earlier filing, WSR 17-10-074, which we also opened.
How to measure a shower the way the codes do
The steps below follow the points the two state texts name. Run the same steps on every shower you are comparing, and write down each figure with its height.
- Measure the finished interior. Both state texts use the words “finished interior.” Measure the space between the finished wall surfaces, not the studs or the rough opening.
- Find the threshold height. Washington measures the area and the circle at the top of the threshold. Mark that height on the wall and measure there.
- Find the control handle height. Minnesota measures the 30 inch circle at the height of the shower control handles, with the door or curtain closed. If the handles sit at a different height from the threshold, measure at both heights and check each rule against its own point.
- Check the circle. Confirm that a 30 inch circle fits at each height. A square interior that is 30 inches on each side is just large enough to hold a 30 inch circle.
- Check the area. Multiply the width by the depth, both in inches. The minimum in both state texts is 900 square inches. To convert to square feet, divide the square inches by 144. This is arithmetic from the stated figures, not a separate code requirement.
- Check the height. If you are in Washington, check that nothing other than the allowed items reduces the space up to 70 inches above the drain outlet. Note any seat, bench or fixed bracket that sticks into the space.
Use a tape measure marked in inches and a level for the threshold. If a step would change the drain, the supply, or the valve, leave that work to a licensed plumber and do not rely on these measurements alone to decide what can be changed.
Why the numbers differ
The two state texts agree on the 900 square inch area and on the 30 inch circle. They disagree on where the measurement is taken. Minnesota uses the height of the control handles. Washington uses the top of the threshold and adds a 70 inch height rule. The ADA figures are a different kind of rule: they are clear inside dimensions for accessible compartments, and they are larger than the state minimums.
A shower that meets one of these figures can fail another. A shower with handles set higher than the threshold may pass a circle test at the threshold and fail one at the handle height, or the reverse. The sources do not say which height controls for a particular house. They also do not describe how other states handle these points. The Minnesota and Washington texts are two state rules, and the sources do not show how other states write their own versions.
Mistakes to avoid
- Measuring to the studs. Both state texts use the finished interior, so the stud dimension is the wrong number for a code check.
- Measuring at one height only. Minnesota uses the control handle height and Washington uses the threshold. A single reading may not answer both.
- Treating the ADA sizes as the general rule. The 30 by 60 and 36 by 36 inch figures are accessibility sizes from the ADA text. They are not the general minimum in the state texts.
- Assuming a remodel is exempt everywhere. The Minnesota text exempts showers installed in remodeling from the 30 inch width rule, and nothing in the Washington section 408.6 text we opened exempts remodels.
- Ignoring the 70 inch height. Washington’s dimensions must hold to 70 inches above the drain outlet, so a fixed bracket at a low height can matter.
Next steps after you measure
Once you know the size of the space, the next question is usually which head fits it and how it performs. Our guides to showerheads for low water pressure and to adding a rain shower head cover those choices. Neither post answers the code question on this page, so check the figures here first.
What we could not verify: what the sources do not say
- Typical sizes. None of the three sources gives the size of a typical shower in a home. Not stated.
- A single national standard. None of the sources gives one. The Minnesota and Washington figures come from two state rules, and the ADA figures come from federal accessibility text.
- Whether these rules apply to your house. The sources do not say how a given state or town adopts these texts. Check with your local building or plumbing office.
- Roll-in and transfer sizes in a home. Only the ADA text gives 30 by 60 and 36 by 36 inches. That is one source for each figure.
- Tile thickness and wall finish. The sources say “finished interior” but do not say how to treat tile thickness or wall finish when you measure.
- Other states. The sources cover Minnesota, Washington and the federal ADA text only.
- Products. The sources do not say which shower enclosures or heads meet these figures. This post does not review products.
FAQ
What is the standard shower size?
The sources do not give one size for a standard shower in a home. They give code minimums: 900 square inches of finished interior and room for a 30 inch circle in Minnesota and Washington, and accessible sizes of 30 by 60 inches for a roll-in shower and 36 by 36 inches for a transfer shower in the ADA text.
Is 36 by 36 inches a standard shower size?
The ADA text gives 36 by 36 inches for a transfer type shower compartment. That is one source for one accessible type. The sources do not describe it as a general standard for all showers.
Is 30 by 60 inches the standard walk-in shower size?
The ADA text gives 30 by 60 inches for a standard roll-in type shower compartment. The sources do not say that every walk-in shower must be that size.
Does a 30 by 30 inch shower meet the code?
A 30 by 30 inch interior equals 900 square inches, which is arithmetic from the stated figures. A square interior of that size can also hold a 30 inch circle. The sources state both figures, but they do not say a 30 by 30 inch shower is the standard size.
Are these figures measured to the tile or to the studs?
Both state texts use the term “finished interior.” The sources do not say how to treat tile thickness, so measure the finished surfaces and note the tile allowance you used.
Do these rules apply to a remodel?
The Minnesota text says the 30 inch requirement does not apply to showers installed in remodeling. The Washington text we opened has no remodel exception in section 408.6. Check your local code before you plan a remodel.
Bottom line
Start from the code that applies where you live. The Minnesota and Washington texts show the core figures: 900 square inches of finished interior and room for a 30 inch circle, measured at the height each state names. For accessible design, use the ADA figures. Measure at both the threshold and the control handle height when they differ, write down each number, and check the local plumbing code before you build or remodel.
Sources
- U.S. Department of Justice, 2010 ADA Standards for Accessible Design, section 608 (Shower Compartments). https://www.ada.gov/law-and-regs/design-standards/2010-stds/ (opened 2026-10-27)
- Minnesota Revisor of Statutes, Rule 4715.1380, Showers, subpart 4. https://revisor.mn.gov/rules/pdf/4715.1380/2014-01-18%2005:45:36+00:00 (opened 2026-10-27)
- Washington State Code Reviser, WSR 21-01-125, permanent rules of the Building Code Council, section 408.6 (effective January 15, 2021). https://lawfilesext.leg.wa.gov/Law/WSR/2021/01/21-01-125.htm (opened 2026-10-27)
- Washington State Code Reviser, WSR 17-10-074, section 408.6 (earlier filing, same text). https://lawfilesext.leg.wa.gov/Law/WSR/2017/10/17-10-074.htm (opened 2026-10-27)
