A visual indicator for denoting a fluid level in a throat portion of a waterless urinal cartridge is presented. The visual indicator comprises a fluid level indicator disposed in the throat portion of the cartridge. As material buildup occurs inside the cartridge, a corresponding rise in the fluid level in the throat of the cartridge may be seen relative to the indicator, indicating when the cartridge will need replacement. The visual indicator may comprise markings that indicate the level of fluid within the throat portion, reactive materials, or an electronic reader. The fluid level indicator may also be made visible by ultraviolet radiation.