Which TDS is Best for Drinking Water?

Did you know? The Bureau of Indian Standards (BIS) recommends that the Total Dissolved Solids (TDS) in drinking water should not exceed 500 mg/L, but the ideal taste and mineral balance often lies somewhere much lower—typically between 150 to 300 mg/L.

So, what does this mean for your daily water intake?
Is lower TDS always better? Or can water that's too pure actually lack essential minerals your body needs?

In today’s world, where RO purifiers are common in every household, understanding the right TDS level is no longer optional—it’s crucial. Too high, and you risk consuming harmful salts or heavy metals. Too low, and you strip your water of vital minerals like calcium and magnesium.

This blog will break down:

• What TDS in water really means

• What levels are considered safe and ideal

• How RO purifiers affect TDS

• And how to measure and manage the TDS in your drinking water

What is TDS in Drinking Water?

TDS stands for Total Dissolved Solids—a measurement of all organic and inorganic substances dissolved in water. These can include:

• Essential minerals (calcium, magnesium, potassium)

• Salts (sodium, bicarbonates)

• Metals (iron, lead, arsenic in unsafe cases)

• Organic matter (natural or manmade)

TDS is expressed in parts per million (ppm) or milligrams per liter (mg/L). While many dissolved solids are necessary for health, high concentrations can affect taste, smell, and even safety.

Common Sources of TDS:

• Natural groundwater minerals

• Agricultural runoff

• Sewage or industrial waste

• Water treatment chemicals

TDS doesn’t identify which substances are present—only the total quantity. This is why understanding the ideal range is essential for drinking safety.

What is the Safe TDS Level for Drinking Water?

The safe TDS level for drinking water, as per the Bureau of Indian Standards (IS 10500:2012), is:

💡 Ideal Range: 150–300 ppm – This range offers a healthy mix of minerals and good taste, making it the sweet spot for most drinking needs.

When TDS goes too low (below 50 ppm), water loses essential electrolytes and tastes bland. On the other hand, excessively high TDS (over 500 ppm) may contain harmful substances, especially if the source is industrial or agricultural.

What is the Ideal TDS for RO Water?

Reverse Osmosis (RO) systems are designed to purify water by pushing it through a semi-permeable membrane that filters out dissolved solids. This often reduces the TDS to very low levels—sometimes below 30 ppm.

But is that good?

Not always.

While RO is excellent at removing harmful contaminants, it also strips away essential minerals, which the body needs for bone health, muscle function, and overall wellness.

Ideal TDS for RO Water:

• 100–250 ppm is optimal after RO filtration.

• Anything below 80 ppm often tastes flat and lacks vital minerals.

• Many RO systems now come with TDS controllers or mineral cartridges to reintroduce healthy minerals into purified water.

If you're using an RO purifier, it’s important to:

• Test the TDS before and after filtration

• Ensure remineralization, especially for children, elderly, or daily consumption

Understanding TDS Level in Water Purifier Systems

Today’s water purifiers—especially multi-stage RO+UV+UF systems—often reduce TDS drastically. Here’s what you need to know about managing TDS through these systems:

How to Measure TDS in Your Water Purifier:

• Use a digital TDS meter (affordable and easy to use)

• Measure input TDS (raw water) and output TDS (filtered water) regularly

• Maintain TDS around 150–250 ppm post-filtration

What Affects TDS in Water Purifiers?

1. Membrane quality – Old or damaged membranes may allow contaminants through.

2. TDS Controller – Adjusts the mix of RO-purified water and raw water.

3. Mineral Cartridge – Adds back essential minerals like calcium and magnesium.

4. Annual Servicing – Prevents malfunctioning of filters and TDS drift.

💡 Tip: If your water source already has a TDS of 100–300 ppm, you may not need an RO system. A UV or UF filter could suffice, retaining natural minerals.

Comparison Table: TDS Level vs. Water Quality

How to Adjust or Improve TDS in Drinking Water

If your water’s TDS level isn't within the ideal range, here’s how to correct it:

1. Install a TDS Controller

• Blends RO-purified water with raw water to reach ideal TDS.

• Most RO+UV systems support this feature.

2. Use Mineral Cartridges

• Adds calcium, magnesium, and trace elements to enhance water quality.

• Restores taste and nutritional value post-purification.

3. Switch to UV/UF Filters for Low-TDS Water Sources

• These systems disinfect without altering TDS.

• Preserves natural minerals if your input water is already safe.

4. Regular Maintenance

• Clean filters and replace membranes to prevent over-filtration or contamination.

• Monitor TDS every 3 months for stable water quality.

Also Read - What is the Minimum TDS for Drinking Water? A Complete Guide

Common Myths About TDS in Drinking Water

Let’s clear up some misconceptions:

❌ Myth 1: Lower TDS means healthier water

✅ Truth: Ultra-pure water can lack minerals your body needs.

❌ Myth 2: RO always gives the best water

✅ Truth: Not if your source water is already within the ideal TDS range. RO may over-filter in such cases.

❌ Myth 3: All high TDS water is dangerous

✅ Truth: Not always. Some mineral-rich water (like from springs) can be high in TDS but still safe, depending on the content.

FAQs – Which TDS is Best for Drinking Water?

Q1. What is the best TDS level for drinking water?

Answer: The ideal TDS for drinking water is between 150 to 300 ppm for balanced minerals and taste.

Q2. Is RO water with very low TDS safe?

Answer: While safe from contaminants, RO water with TDS below 50 ppm may lack essential minerals and taste flat. Remineralization is recommended.

Q3. How can I check the TDS of my drinking water?

Answer: Use a digital TDS meter. Simply dip the probe into a water sample and read the TDS level on the screen.

Q4. Should I always use an RO purifier?

Answer: Only if your water source has TDS above 300 ppm or contains contaminants. Otherwise, UV/UF filters might be sufficient.

Also Read - Is 25 TDS Safe for Drinking Water?

Conclusion

So, which TDS is best for drinking water?
The answer lies in balance. A TDS level between 150–300 ppm not only ensures safety but also preserves essential minerals that support your health.

If your TDS is:

• Too high: Use an RO purifier with a TDS controller.

• Too low: Add a mineral cartridge or blend in safe raw water.

• Ideal already: Stick with a UV/UF purifier to preserve natural minerals.

📌 Final Tip: Test your water’s TDS regularly, adjust your purifier settings, and ensure you’re drinking water that supports—not subtracts from—your health.