How Many Portable Restrooms Do You Need? A Planning Guide for Flathead Valley Events and Job Sites

The right number of portable restrooms depends on how many people you expect, how long they will be there, whether food and drinks are served, and how often the units get serviced. Headcount alone will get you close, but the other factors are what keep lines short and units clean all day. This guide walks through how we think about it at Big Sky Site Services, whether you are planning a backyard reunion in Bigfork or a six-month build in Kalispell.

If you would rather skip the math, call us at (406) 416-5607 or request a quote. Tell us your headcount, dates and site and we will recommend a setup.

Start with headcount and hours

The two biggest numbers are how many people will be on site at the same time and how many hours they will stay. A two-hour afternoon gathering and an all-day festival with the same guest list need very different setups.

Many rental guides use a rough starting point of about one standard unit per 50 guests for an event of around four hours, then add units as the event gets longer or busier. Treat that as a general guideline, not a rule. It is a place to start the conversation, and we will adjust it for your event.

Things that push the number up

• Food, beer and other drinks. When drinks are flowing, restroom traffic climbs quickly. Plan extra units near the bar or food area.
• Longer events. All-day and multi-day events need more units, more frequent service, or both.
• Peak moments. Intermissions, halftime and the end of a ceremony send everyone to the restrooms at once.
• A spread-out site. On a big field or a long trail course, a few units in several spots usually work better than one large bank.
• Families with kids. Children need more frequent trips and a little more time.

Things that can bring it down

• Shorter events with a light food and drink menu.
• Indoor restrooms on site that some guests can use.
• A mid-event service visit, which can stretch a smaller setup further.

Job sites: plan by crew size and schedule

Construction is a little different because the same crew uses the units every day. OSHA’s construction sanitation standard (29 CFR 1926.51) sets minimum toilet facilities based on the number of workers, starting with at least one toilet for small crews and adding more as the crew grows. Check the current rule for your crew size, and plan above the minimum if you run long shifts or bring in extra trades at certain stages.

Service schedule matters just as much as unit count. Most long-term portable restroom rentals on job sites get regular weekly service, and busy sites may need more. Tell us your crew size and work hours and we will suggest a schedule that keeps units clean and stocked.

Don’t forget ADA-accessible units

Accessible units are larger, sit at ground level and have room for a wheelchair to turn around. Under the 2010 ADA Standards, when portable units are grouped together, at least 5 percent of them (and never fewer than one) generally need to be accessible. Public events and permitted sites may have their own requirements, so check with your permit office. When in doubt, include at least one ADA unit in every bank of restrooms.

Add handwash stations

Many standard units have hand sanitizer, but sanitizer is not the same as soap and running water. Freestanding handwash stations are a good idea anywhere people eat, and they are often required around food service. Place them near the restrooms and near food areas so guests use them without going out of their way.

When a restroom trailer makes more sense

For weddings, corporate events and VIP areas, a restroom trailer gives guests flushing toilets, real sinks and a climate-controlled room. One trailer can stand in for several standard units at a dressy event, and many hosts pair a trailer for guests with a few standard units for vendors and staff. If you are weighing the two, our guide to restroom trailers vs. portable restrooms for a Montana wedding goes deeper.

Placement tips for Northwest Montana sites

• Level, firm ground. Units need a flat spot. Let us know about slopes, soft lawns or gravel pads ahead of time.
• Truck access. Our service truck needs to reach the units. Think about gates, low branches, septic fields and soft spring ground.
• Lighting for evening events. If people will use the restrooms after dark, a light tower or good path lighting makes a big difference.
• Weather. Summer afternoons can get hot and wind can pick up near the lake. We stake or position units with the weather in mind.

A quick planning checklist

1. Expected headcount at the busiest time of day.
2. Start and end times, and the number of days.
3. Food, beer or other drinks served (yes or no, and how much).
4. At least one ADA-accessible unit.
5. Handwash stations near restrooms and food.
6. A service visit for long or multi-day events.
7. Delivery access and a level spot for each unit.

We deliver from our base in Whitefish across the Flathead Valley and Northwest Montana, including Columbia Falls, Polson and Lakeside. Portable restrooms start at $150 per event and handwash stations at $95, with delivery at $85 per trip for up to 4 standard units or hand-wash stations. See portable restroom rates for the full list.