Chlorine Dioxide and Unusual Odors
The City of Mesa uses chlorine dioxide gas as a disinfectant
at the water treatment plant. Chlorine dioxide is used instead
of chlorine to reduce the formation of cancer causing compounds
such as trihalomethanes. It is an excellent disinfectant but
can cause short-term odor problems for customers.
When a water tap is opened, small amounts of chlorine dioxide
diffuse into the air and combine with existing household odors.
All homes have volatile organic compounds (VOCs) in the ambient
air produced by scented products (soaps, candles, air
fresheners, incense, potpourri), cleaning agents or solvents,
paint, carpet, furnishings, fresh flowers or wreaths, and many
other common household items. The VOC/chlorine dioxide
combination odors have been described as smelling like fuel oil,
kerosene, chemicals or cat urine, to name the most common.
Studies have not identified any health concerns associated with
this combined odor.
The strongest odors are associated with installing new
carpet, upholstered furniture or draperies and interior
painting. The odor will continue until the level of VOCs
decreases (new smell goes away). This can take from a few weeks
up to several months to dissipate depending on the situation,
type of materials, amount of ventilation, etc. In enclosed areas
with little ventilation, such as laundry rooms, basements,
bathrooms and closets, these compounds will accumulate, so the
odor will tend to be stronger or last longer than in well-ventilated areas. Increasing ventilation by opening windows and
turning on fans will help to eliminate the odors more quickly.
Alternatively, you can remove chlorine dioxide and other
chlorine compounds from the water by using an activated carbon
filter. This will prevent the formation of compounds causing
If you have any questions, please call the Water Quality
division at 480-644-6461.