Industrial Locker Rooms and Shower Buildings in California: HCD Approval, Sizing, and What to Expect

Ports, refineries, manufacturing plants, and industrial job sites across California add locker room and shower space the same way they add office space — with a modular building. This guide covers how these buildings get approved in California, what they typically include, and what to expect on cost and timeline.

Who uses these buildings in California

Locker room and shower trailers show up most often at ports, refineries, manufacturing plants, and other heavy-industry sites where a workforce needs to change, wash up, and store gear before and after a shift. The requirements are consistent across these industries: heavy-duty finishes that hold up to daily industrial use, secure storage, and utility connections sized for real usage — not the lighter-duty fixtures that work fine in a school or office building.

HCD approval, not DSA

Industrial locker room and shower buildings go through California’s HCD (Housing and Community Development) approval track — the same commercial track used for offices, break rooms, and other non-school modular buildings. That’s a different, generally faster process than the DSA (Division of the State Architect) approval schools go through. If you’re weighing the difference, our guide to converting a DSA building to HCD walks through both tracks in detail.

Occupancy-wise, an industrial locker room or shower building is typically classified under Group F (Factory/Industrial) when it supports a manufacturing, refinery, or port operation — the same classification that applies to dispatch offices and control rooms at those sites. Occupancy classification drives fixture counts, exit requirements, and permitting complexity, so it’s worth confirming early. Our California occupancy classifications guide covers Group F and the other CBC occupancy groups in full.

What’s typically included

Most industrial locker room and shower buildings are built as “wet” buildings — meaning they include plumbing and require a water and sewer connection on site, as opposed to a “dry” building with no plumbing. Common features:

Industrial-grade lockers — secure, heavy-duty units sized to the workforce, sometimes with separate storage or an attendant area.
Showers and restrooms — separate male and female facilities are standard for a workforce-serving building; a smaller building may use a single ADA-compliant unisex restroom instead.
Benches and seating in the locker area.
Drainage built for daily shower use, not the occasional-use plumbing found in a standard office restroom.
Water heating sized for the fixture count — a real factor in both equipment selection and monthly utility cost once the building’s in service.
Heating and air conditioning, since these buildings are occupied year-round in most California climates.

Accessibility is non-negotiable: California enforces CBC Chapter 11B, which is generally at least as strict as federal ADA and governs wherever the two differ. Our ADA requirements guide covers the ramp, clearance, and restroom accessibility standards that apply to any California modular building, including these.

Common sizing for industrial locker & shower buildings

Every workforce is different, but two configurations come up often enough to be useful starting points:

Configuration	Size	Typical use
60′ × 60′	3,600 SF	Offices, training area, kitchen, restrooms, and showers combined — a mid-size industrial complex
72′ × 60′ (6-wide)	4,320 SF	Open office, training room, conference room, break room, locker rooms, showers, restrooms, and kitchen — the largest standard complex, built for a full industrial workforce

Smaller sites often start with a dedicated single-purpose locker/shower trailer rather than a full multi-department complex — the right starting point depends on headcount, shift structure, and what other space (offices, break rooms) the site already has.

Foundation and seismic considerations

A wet building carries more weight and more risk if it shifts — water lines and drains don’t tolerate movement the way a dry office does. Foundation selection matters more here than on a comparable dry building. Our foundation systems guide covers the options, and our seismic design guide explains how Seismic Design Category affects foundation requirements across California.

What this means for cost and timeline

A wet building costs more than an equivalent dry building — the plumbing, water heating, and drainage all add to both the equipment price and the site-connection scope. Site work (water line to the building, sewer connection, and any backflow or chlorination requirements) is typically handled by a plumbing contractor on site and isn’t included in the building price itself. The building portion can often move faster than the site-work permitting, so it’s worth starting the utility conversation with your site engineer early rather than after the building is ordered.

Frequently asked questions

Do we need DSA approval for an industrial locker room building?
No — DSA applies to public school construction. An industrial locker room or shower building at a port, refinery, or plant goes through California’s HCD commercial track instead.

Can we rent a shower/locker trailer instead of buying?
Yes. Rental and lease options exist alongside purchase, and which makes sense depends on how long the space is needed and whether the project is temporary or ongoing.

Do we need separate male and female facilities?
For a workforce-serving building, separate facilities are standard. Smaller or lower-headcount sites sometimes use a single ADA-compliant unisex restroom instead — worth discussing against your actual headcount and shift pattern.

Related California resources

Planning locker room or shower space for a California industrial site? Call (800) 806-7485 or request a quote and we’ll help you size it to your actual workforce and site conditions.

iModular.com — California modular building specialists since 1998. Last updated September 2026.