What Is the Ideal TDS for Drinking Water?

The Ideal TDS Range

According to the World Health Organization (WHO) and India’s Bureau of Indian Standards (BIS IS 10500:2012), the ideal TDS for drinking water is:

• BIS acceptable limit: 500 ppm
• BIS maximum permissible: 2000 ppm (in absence of alternative source)
• WHO recommended: 300 ppm (for palatability)
• WHO maximum: 600 ppm (for taste acceptability)

Most people find water with TDS between 150–300 ppm to taste best. Water below 50 ppm tastes flat or “empty,” while water above 500 ppm starts tasting salty, bitter, or metallic.

How TDS Affects Taste

TDS Range (ppm)	Taste	Palatability
0–50	Flat, insipid	Poor — lacks minerals
50–150	Fresh, light	Good
150–300	Balanced, pleasant	Excellent — most preferred
300–500	Noticeable mineral taste	Acceptable
500–900	Salty or bitter	Poor
900–2000	Very salty	Unpalatable
2000+	Undrinkable	Unacceptable

Health Implications of TDS

Low TDS (below 50 ppm):

• Lacks essential minerals like calcium and magnesium
• May leach minerals from the body through osmosis
• Not recommended for long-term drinking
• Common problem with RO purifiers that strip all minerals

Moderate TDS (150–400 ppm):

• Provides beneficial minerals
• Good for hydration
• Safe and pleasant to drink

High TDS (above 1000 ppm):

• May cause gastrointestinal irritation
• Can contain toxic components (arsenic, lead, fluoride)
• Damages appliances and plumbing
• Requires RO treatment

The RO Mineral Strip Problem

RO purifiers remove 90–95% of TDS, often producing water with 10–50 ppm TDS. This is below the ideal range. Some modern purifiers address this with:

• TDS controllers: Bypass a small amount of raw water to maintain mineral content
• Mineral cartridges: Add back calcium and magnesium after RO
• RO+UV+Mineral: Systems that balance purification with mineral retention

When buying an RO purifier, look for one with a TDS adjuster or mineralizer to keep output TDS in the 100–200 ppm range.

TDS Is Not the Full Picture

TDS tells you the total quantity of dissolved solids but not their composition. Water with 300 ppm TDS could be:

• Mostly beneficial calcium and magnesium — excellent water
• Mostly sodium and chloride — salty but generally safe
• Mostly nitrates or heavy metals — dangerous

Always get a lab test to understand what makes up your water’s TDS, especially if it exceeds 500 ppm.

Key Takeaways

• The ideal TDS for drinking water is 150–300 ppm for taste and health
• BIS acceptable limit is 500 ppm; maximum permissible is 2000 ppm
• RO purifiers often produce water with very low TDS (10–50 ppm), which lacks minerals
• Look for RO systems with TDS controllers or mineralizers to maintain healthy TDS levels
• TDS alone does not tell you about water safety — test for specific contaminants too