Start with the base table
Event sizing is driven by two numbers: guest count and hours. The standard planning baseline assumes a roughly 4-hour event with a balanced crowd:
| Guests | Standard units (≈4 hrs) |
|---|---|
| Up to 50 | 1 |
| 51–100 | 2 |
| 101–250 | 3–4 |
| 251–500 | 6–8 |
| 501–1,000 | 12–16 |
| 1,000+ | ~1 unit per 65–75 guests, then adjust |
That's the starting point, not the final answer. Two factors move it.
Adjustment 1: duration
The longer the event, the more each unit gets used. Add roughly 15–20% capacity for every hour beyond four. An 8-hour festival needs meaningfully more units than the base table shows for the same headcount.
Adjustment 2: alcohol
Alcohol and food service increase restroom trips substantially. If you're serving drinks, plan for roughly 15–30% more units than the dry-event baseline. Weddings, beer festivals, and concerts all land at the high end.
Adjustment 3: crowd mix
A crowd skewing heavily female, or events with lots of families and kids, use restrooms more. When in doubt, round up — one extra unit is cheap next to a 20-minute line.
ADA — not optional
Events open to the public must provide accessible restrooms under the ADA. The working rule: at least one ADA-compliant unit, and generally about 5% of your total units (minimum one) should be ADA. Place them on firm, level ground with a clear path — an ADA unit at the bottom of a muddy slope doesn't count as accessible.
Hand-wash stations
Any event serving food should provide hand-wash capacity. A common planning ratio is one hand-wash station per two to four restroom units, more where food handling is heavy. Health rules in Harris County can layer additional requirements on food-present events — build hand-wash in from the start rather than bolting it on.
Service frequency for multi-day events
A single-day event is usually a drop-and-pickup. Multi-day events (festivals, fairs) need servicing between days, sometimes twice daily at high traffic. Every SolidSite service visit is documented with a timestamped photo, so you know the units were actually pumped and restocked — not just "scheduled."
Placement tips that save the day
- Spread units across the site rather than clustering them at one gate.
- Keep them off the main sightlines but on solid, reachable ground.
- Light them if the event runs past dusk.
- Put hand-wash stations next to food, not next to the exit.
How SolidSite sizes your event
Give your rep the guest count, hours, whether alcohol is served, and the site layout, and we'll size the exact unit count, ADA coverage, hand-wash stations, and service schedule — then place them where the crowd actually is. Standard, ADA, and hand-wash units are available; flushing restroom trailers for upscale events are quoted separately.