Guide · Fontana, CA

What Is the Blue Liquid in Porta Potties?

It is a deodorizer, and its color tells you when the unit needs service. Here is what it does and what it cannot do.

By Fontana, owner · Reviewed October 14, 2026

What is the blue liquid in a porta potty?

The blue liquid in a porta potty is a deodorizing chemical mixed with water and poured into the holding tank after each pump-out. It controls odor, slows the bacteria that cause smell, and uses blue dye so users cannot see the tank contents. A fresh charge goes in at every service visit.

Is porta potty blue liquid safe?

Porta potty blue liquid is safe for normal use, because people never touch it and it sits below the seat. Modern deodorizers are mostly biodegradable, formaldehyde-free formulas. Do not pour other chemicals, bleach or trash into the tank, because they can react with the deodorizer and make cleaning harder.

Why does the blue liquid turn green?

Blue liquid turns green, then brown, as the tank fills and the dye gets diluted. Green is a sign the tank is nearing the point where it needs service. On busy Fontana summer sites, the change happens faster, which is why heavy-use units get a second weekly service.

Does the blue liquid stop porta potty smell in the heat?

Blue liquid reduces porta potty smell but cannot stop it alone when temperatures pass 95°F. Heat speeds up bacteria. In Fontana summers, placing the unit in shade, keeping the vent clear, closing the lid and adding a service visit do more than extra chemical.

More on heat: keeping porta potties fresh and upright in Fontana heat and wind.