Porta potty calculator

How the calculator works

These are the rules we size every East Texas event and job site with.

Events

• 1 restroom per 50 people on site for an event of up to about four hours. Staff, volunteers, and vendors count. If guests come and go, it is the crowd there at once that matters: 1,000 guests over a ten-hour day who each stay about three hours is roughly 300 people on site.
• +20% if alcohol is served. People drink more and go more often.
• +20% if most guests are women. The base ratio assumes a mixed crowd.
• +20% if the event runs past six hours.
• The adjustments stack. A 200-guest reception with a bar that runs seven hours is 4 base units × 1.2 × 1.2, which rounds up to 6.
• Permanent restrooms count. Flushing toilets guests can use come off the total, one for one.

Service and tank capacity

• A standard unit holds about 200 uses before it needs pumping. That figure comes from the Portable Sanitation Association International's special event chart.
• People go about once every four hours. For a one-day event, the count above almost always covers it and we service at pickup. For a long day or a multi-day event, the calculator checks whether the units would fill first, adds units if needed, and tells you how often to service: daily, every few days, or more than once a day.

Job sites

• 1 restroom per 10 workers on a 40-hour week, serviced weekly. Longer weeks or a second shift count as more hours, so a 25-person crew working 50 hours needs 4 units, not 3.
• Never below the OSHA minimum. OSHA 1926.51 requires 1 toilet for up to 20 workers, then 1 per 40, and 1 per 50 past 200. Our count is higher on purpose: the legal minimum is the point where lines start, not where they end.

Texas mass gatherings

• An event outside city limits with more than 2,500 people who stay more than five hours is a mass gathering under Texas Health & Safety Code Chapter 751. It needs a county permit, and state rules require no more than 50 people per toilet seat, separate men's and women's restrooms, and hand washing at every restroom location. If most of the crowd is under 21 and alcohol is involved, the rules start at 500 people.
• Some national charts size big festivals at a fraction of that, closer to 1 per
  200. Outside city limits in Texas, that count is not legal. Ours never goes below the state ratio.

Accessibility

• Public events need ADA-accessible units: 5% of the restrooms, and never fewer than one. That is the federal ADA standard for clustered portable toilets. Private parties are not held to it, but one accessible unit is worth it whenever older guests are coming.

Hand washing

• One hand-wash station for every four restrooms when food is served, placed where people leave the restrooms and near the food line. At a Texas mass gathering, hand washing is required at every restroom location, food or not.

Restroom trailers

• A 2-station trailer handles about 100 guests, a 3-station about 100 to 200, and an 8-station 400 or more with attendant service. Between 200 and 400 guests, call us. The right answer is usually a trailer plus a few standard units.

What the calculator cannot see

The count is a starting point. A few things change it, and they come up when we quote:

• A spread-out site. Restrooms more than a short walk apart work like separate events. A festival with a far parking lot needs units at both ends.
• Summer heat. August in East Texas means more water, and more trips.
• A job site that grows. Start with what the crew needs today and add units as trades come on. Swapping counts mid-job is normal.

For the reasoning behind each rule, and the two mistakes that cause most restroom problems at events, read how many porta potties you need. For budgeting, see what a porta potty rental costs.

Get it sized for you

Call (903) 236-4019 or send the form with your date, location, and headcount. We will confirm the count and quote it, delivered from our yards in Longview, Tyler, Kemp, Mt. Pleasant, and Whitewright. For weddings, festivals, and private parties, see event restroom rentals.