Fact Sheet: Total Dissolved Solids (TDS)

Brief Overview:
Category: Inorganics
Acceptable Level: 500 mg/L
Follow up:
Naturally occurring
Short and Long-term Health Effects
Test for Total Dissolved Solids and Hardness
Distillation, Reverse Osmosis, and Electrodialysis
In some cases, a water softener may be a cost effective treatment.
Source: Total Dissolved Solids are found naturally in the environment. Total Dissolved Solids are a
contaminant found in the National Secondary Drinking Water Regulations. The EPA does not enforce these
“secondary maximum contaminant levels.” They are established only as guidelines to assist public water
systems in managing their drinking water for aesthetic considerations, such as taste, color, and odor. These
contaminants are not considered to present a risk to human health at the secondary maximum contaminant
The EPA believes that if these contaminants are present in your water at levels above these standards, the
contaminants may cause a great number of people to stop using water from their public water system even
though the water is actually safe to drink.
Secondary standards are set to give public water systems some guidance on removing these chemicals to
levels that are below what most people will find to be noticeable. These problems include: aesthetic,
cosmetic, and technical effects.
Aesthetic effects – undesirable tastes or odors.
Cosmetic effects – effects which do not damage the body but are still undesirable.
Technical effects – damage to water equipment or reduced effectiveness of treatment for other contaminants.
Problems associated with Total Dissolved Solids include but are not limited to: hardness, deposits, colored
water, staining, and salty taste.
Effect: Short-term: potentially undesirable tastes, odors, and/or staining
Long-term: potentially damage to plumbing, pipes, fixtures, water treatment equipment and
reduced effectiveness of water treatment equipment.
Follow up: Treat and re-test for Total Dissolved Solids
Treatment: Distillation, Reverse Osmosis, and Electrodialysis
Please note: Treatment for total dissolved solids can be costly. An alternate way of
eliminating the effect of total dissolved solids may, in some cases, be to install a water
softener. While the water softener will not appreciably affect the total dissolved solids it will
reduce or eliminate scaling due to hardness.
Following installation of this system, the consumer should have the treated water tested for Total Dissolved
Solids to verify Total Dissolved Solids reduction is being achieved and the system is functioning properly.
For more information visit the USEPA web site: