What is TDS, and why can it change after using a LifeStraw filter?Updated 2 hours ago

Total Dissolved Solids (TDS) is a measure of dissolved minerals and salts in water, such as calcium, magnesium, sodium and potassium.

A handheld TDS meter does not identify specific contaminants. It measures electrical conductivity and converts that reading into an estimated TDS value.

Is a higher TDS reading bad?

Not necessarily. Naturally occurring minerals contribute to TDS, so a higher reading does not by itself indicate that water is unsafe or that a filter is not working properly.

TDS is not used by LifeStraw to measure filtration performance. Our products are tested for the specific contaminants they are designed to reduce.

Why can TDS increase after LifeStraw filtration?

LifeStraw Home is designed to reduce specific contaminants while allowing naturally occurring minerals to remain in the water.

The activated carbon + ion exchange filter can also change the balance of dissolved ions in the water as it captures certain metals and exchanges them for other common ions.

Because TDS meters estimate TDS from electrical conductivity, this change in ionic composition can sometimes result in a higher reading after filtration.

The membrane microfilter does not remove dissolved minerals and would not be expected to cause the increase.

A higher TDS reading alone does not tell you what substances are present in the water. Identifying individual minerals or contaminants requires specific laboratory testing.