Under the Chicago Plumbing Code as applied to temporary events, a gathering with more than 30 people present needs at least 2 toilets, and once it passes 600 people it needs 1 more toilet for every additional 300 people or fraction of 300. Treat that as a minimum and confirm it with the permit office.
Key takeaways
- Chicago code, as it applies to temporary events, sets the minimum: more than 30 people present needs at least 2 toilets, and more than 600 people needs 1 toilet for every additional 300 people or fraction of 300.
- The code number is a floor. Event length, alcohol, food service, weather and the age of your guests all push a sensible count above it.
- The Chicago Marathon, the Pride Parade and Lollapalooza show how the same question looks at 50,000 or 400,000 people, but nobody should copy their numbers for a smaller event.
- Accessible units belong in an event plan from the start. The Marathon puts standard and ADA portable toilets at each of its aid stations.
- Your provider supplies and services the units, and the permit office confirms the rule for your event. We do not promise that any count will satisfy a reviewer.
What does the Chicago rule say about toilets at an event?
For a temporary event, toilets must meet the minimum quantity in the Chicago Plumbing Code. More than 30 people present needs at least 2 toilets. More than 600 people needs 1 toilet for every additional 300 people, or fraction of 300. Confirm the exact count for your event with the city.
The City of Chicago's guidance on temporary buildings and events points to the Chicago Plumbing Code for the minimum number of toilets. Two lines in that guidance matter most for planning. The first is a floor of at least 2 toilets once more than 30 people are present. The second is a step rule for large crowds: past 600 people, add 1 toilet for every additional 300 people or fraction of 300.
The phrase 'or fraction of 300' is easy to skip and it matters. It means a partial block of 300 counts as a whole one. If your crowd lands 20 people past a multiple of 300, you add a toilet for them.
One caution on how far to take this. The guidance we have gives the thresholds, but it does not spell out the base count that applies at exactly 600 people. Do not compute a total from this page and treat it as final. Ask the permit office for the figure that applies to your event, and give the provider that number.
How do I count the people at my event?
Count the people present at the busiest moment, not the number of invitations or tickets sold. The code speaks of people present, so a peak headcount is the safer basis. If you are unsure, plan on the larger number and tell your provider how you reached it.
Organizers tend to count three different ways. Some count invitations sent, some count tickets or registrations, and some count the people actually standing in the space at the busiest time. The rule speaks of people present, so the peak headcount is what matters.
A wedding with a guest list is easy: guests, plus the people who work the event, such as caterers, a band and staff. A free street festival is harder, because people drift in and out. For those, ask the festival organizers or the permit office how a crowd is counted, and plan for the high point of the day.
Staff and vendors count too. Vendors who set up booths at a festival are on site for many hours, often longer than any visitor, and they use the same toilets.
What does the minimum look like at different crowd sizes?
Up to 30 people the code sets no minimum in the guidance we reviewed. Above 30 people it asks for at least 2 toilets. Above 600 it adds 1 toilet per extra 300 people or fraction. The table shows where each step starts without computing a total.
The table below lays out the steps in the rule exactly as the guidance states them. It deliberately avoids totals above 600, for the reason given earlier. Use it to see which band your event falls in, then ask for the number that applies.
| People present | What the rule asks for | What to do next |
|---|---|---|
| 30 or fewer | The guidance we have states no minimum at this size. | Still plan for comfort. A small party with no toilet nearby is a problem for guests. |
| More than 30 | At least 2 toilets. | Tell the provider your peak headcount and ask for 2 as the starting point. |
| More than 600 | 1 toilet for every additional 300 people, or fraction of 300, on top of the base count. | Ask the permit office for the base count that applies, then add the step. |
| Each extra block of 300 | Add 1 toilet. A partial block counts as a full one. | Round up when you plan, not down. |
Why is the legal minimum not enough for most events?
The minimum is the least the code accepts, not the number that keeps lines short. Long events, alcohol, food and hot or cold weather all increase use. Plan above the minimum, then ask your provider what count they recommend for your crowd and hours.
A toilet minimum describes a floor. It does not know whether your event lasts three hours or ten, whether people are drinking, or whether the temperature outside is 90 degrees. All of those change how often each unit is used and how long guests wait.
Think about who is coming. A children's festival, a beer garden and a road race all have different patterns. Runners need the toilets all at once, in the minutes before a start. A wedding reception needs them in waves between courses and dances. A parade crowd arrives early and stays.
Servicing matters as much as count. For an all-day event, units can be serviced before the crowd arrives, and a provider may be able to arrange attention during the day as well. Whether that is available depends on the provider and the date, so ask early. For that side of the job see the page on special event portable toilets.
How do the Marathon, Pride and Lollapalooza show the scale?
The 2025 Chicago Marathon had a record 53,000 runners and 20 aid stations, each with standard and ADA portable toilets. The Pride Parade was expected to draw about 800,000 spectators in Lakeview. Lollapalooza is estimated at over 400,000 across four days. They show scale, not a formula.
The Chicago Marathon is a useful example because it is spread out. The 47th running had a record 53,000 runners across 29 neighborhoods, with the start and finish in Grant Park and 20 aid stations one to two miles apart. Each aid station has both standard and ADA portable toilets. The lesson is not the headcount. It is that the toilets go where people gather, and accessible units are in the plan from the beginning.
The Pride Parade is a different shape. In 2025 about 800,000 spectators were expected in Lakeview, and about 1 million across the weekend's festivities. The 54th parade stepped off at 11 a.m. at Sheridan and Broadway and ran south on Broadway and Halsted, east on Belmont and south on Broadway to Diversey. A parade crowd lines a route, so units are placed along it, not at one site.
Lollapalooza in Grant Park has been estimated at more than 400,000 attendees over four days, or more than 115,000 a day. A single-site festival like that concentrates demand in one park. Taste of Chicago, which returned to July, and more than 20 street festivals between May and September fill the rest of the calendar.
None of these events is a template for yours. A neighborhood block party of 150 people is governed by the same code, but its count is a handful, not hundreds. The point is that big events plan toilets as part of the event, and you should too. Our pages on marathon and race toilets and parade and crowd restrooms go into how those layouts work.
What else should I plan beyond the toilet count?
Plan accessible units, handwashing, placement and servicing alongside the count. Put units where people can find them, on firm ground, away from food service, and tell the provider about access to the spot. Confirm every rule with the city before the event, because we cannot promise approval.
Start with accessibility. Public events should include accessible units, and the Marathon's practice of pairing ADA units with standard ones is a sound model. We found no Chicago rule for how many accessible units an event needs, so ask the permit office, and see the page on ADA accessible portable toilets.
Next, handwashing. Where food is served, the Chicago Department of Public Health reviews special-event food booths, mobile food and sampling applications, and food booths at summer festivals need a Summer Festival Food Vendor Sanitation Certificate. Our page on handwashing stations explains the add-on.
Finally, placement. Put the units where guests can see and reach them, on firm, level ground, and keep the approach clear for the provider's truck. Tell the provider about the site, including any gates, steps or crowd barriers, when you order.
How should units be laid out on the day of a big crowd?
Spread units across the site in several banks instead of one cluster, keep them on firm ground away from food service, and leave a clear lane for the servicing truck. Short walks and visible signs of where to go keep lines from building at one end.
Count is only half the plan. A hundred guests will queue at the nearest door if there is only one bank of units, even when the total is generous. Split the units into two or three groups so that no part of the site is a long walk from one, and put the busiest bank near where people gather longest, such as a stage, a beer garden or the finish line of a race.
Think about where a servicing truck can go. The provider needs a lane to reach each bank without driving through a crowd. At a closed-street event that lane is part of the street plan, so raise it with the permit office early. At a lawn event, tell the provider about soft ground, because a heavy truck and a wet lawn do not mix.
Keep toilets and food apart. Handwash stations belong close to both, so people can wash after the toilet and before they eat. Keep one accessible unit on a firm, level path with room to approach it, not at the back of a row on the grass.
Finally, plan for the end of the event. Units are collected after the crowd leaves, and the provider needs to know when the site clears. Ask what the provider needs from you at that point, and keep your permit paperwork handy.
Frequently asked questions
Does a backyard party of 40 people need 2 portable toilets?
The rule we reviewed applies to temporary events and asks for at least 2 toilets once more than 30 people are present. A private backyard may have a house bathroom, which changes the picture. Ask the city whether the rule applies to your gathering.
What does 'or fraction of 300' mean?
It means a partial group counts as a full one. Once you are past 600 people, you add 1 toilet for every additional 300 people, and any leftover group smaller than 300 still earns one more toilet. When you plan, round up, not down.
Who tells me the right number for my event, the provider or the city?
The city sets the minimum, and the provider supplies the units. The Mayor's Office of Special Events can be reached at (312) 744-3315 for event questions. Give your provider the count the city confirms, then ask what they recommend above it.
Do accessible units count toward the minimum?
We could not source a Chicago rule on this, so we do not state one. Ask the permit office whether accessible units count toward your total. Either way, plan at least one accessible unit at a public event so guests who need one can use it.
Is the count different for a race than for a festival?
The same code minimum applies, but the pattern differs. Runners use toilets in a rush before the start, so a start-line bank needs more units than a festival of the same size. See the marathon and race page for how providers plan that.
Sources
- City of Chicago – Temporary buildings and events requirements
- Chicago Marathon – Event information
- Windy City Times – Your guide to the Chicago Pride Parade route, start time and other details
- City of Chicago – Department of Public Health, Food Protection Services for special events
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