The Ultimate Guide to TDS in Drinking Water

Total Dissolved Solids (TDS) is a measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized, or micro-granular suspended form.

Why does TDS matter?

When water travels through rocks and soil, it picks up minerals like calcium, magnesium, potassium, and sodium. It can also pick up harmful substances like lead, arsenic, and nitrates.

TDS is measured in milligrams per liter (mg/L) or parts per million (ppm).

The Ideal TDS Level

According to the Bureau of Indian Standards (BIS) and the World Health Organization (WHO):

• Less than 300 mg/L: Excellent for drinking.
• 300 - 600 mg/L: Good for drinking.
• 600 - 900 mg/L: Fair (may taste salty or metallic).
• Above 900 mg/L: Poor (not recommended without treatment).

How to test your TDS

The easiest way to test your water’s TDS is by using a digital TDS meter. You simply dip the probe into a glass of your water and read the number on the digital display.

Choosing the right purifier based on TDS

As a general rule of thumb:

1. If your TDS is below 300 mg/L: You don’t need an RO. A UV + UF purifier is perfect. RO will unnecessarily waste water and remove good minerals.
2. If your TDS is above 300 mg/L: You need an RO purifier to effectively reduce the hardness and dissolve solids. Make sure it has a Mineralizer (MTDS) to add back essential minerals for taste and health.

Check out our free TDS Calculator to get instant advice based on your exact reading!