What Is TDS in Water and Why Does It Matter for Your Home?
Share
What Does TDS Mean?
TDS stands for Total Dissolved Solids. It measures the total concentration of dissolved substances in water — primarily minerals like calcium, magnesium, potassium, sodium, and bicarbonates. It's expressed in milligrams per litre (mg/L), which is equivalent to parts per million (ppm).
If your RO water purifier has a display showing a number like "280" or "450" — that's the TDS of your tap water in ppm.
What's in the Dissolved Solids?
The dissolved solids in Indian tap water are mostly natural minerals that come from the rock and soil the water passes through. The primary contributors to high TDS in Indian water are:
- Calcium (Ca2+) — the main cause of limescale
- Magnesium (Mg2+) — also contributes to hardness and limescale
- Sodium (Na+) — affects taste but not limescale
- Bicarbonates (HCO3-) — alkalinity buffer
- Sulphates and chlorides — from geological sources and sometimes treatment chemicals
The calcium and magnesium content is what determines water "hardness" — the property that causes limescale, soap scum, and poor lathering.
TDS Levels in Indian Cities
| City | Typical TDS Range | Classification |
|---|---|---|
| Delhi (borewell areas) | 500–700+ ppm | Very Hard |
| Delhi (treated supply) | 350–500 ppm | Hard |
| Jaipur | 400–800 ppm | Very Hard |
| Chennai | 300–600 ppm | Hard to Very Hard |
| Bangalore | 200–500 ppm | Moderately Hard to Hard |
| Hyderabad | 200–450 ppm | Moderately Hard to Hard |
| Mumbai | 100–250 ppm | Soft to Moderately Hard |
| Kolkata | 150–300 ppm | Moderately Hard |
How TDS Affects Your Home
Above 200 ppm — Limescale starts forming
You'll begin to notice white deposits on taps, tiles, and showerheads. A weekly cleaning routine becomes necessary.
Above 300 ppm — Limescale builds quickly
Deposits form within 2–3 days of cleaning. Appliances like geysers and washing machines need descaling every 3–6 months. Showerheads may need monthly attention.
Above 500 ppm — Serious household impact
Limescale forms almost immediately after cleaning. Taps can develop visible deposits overnight. Geysers can suffer significant efficiency loss without regular descaling. This is the reality for many areas of Delhi, Jaipur, and other northern Indian cities.
Does High TDS Make Water Unsafe to Drink?
Not necessarily. The Bureau of Indian Standards (BIS) recommends a desirable TDS of 500 ppm or below for drinking water, with an acceptable maximum of 2,000 ppm. High TDS water isn't automatically unhealthy — but very high levels can affect taste and, depending on what's dissolved, can be a health concern.
For drinking, RO filtration reduces TDS to 10–50 ppm. Most RO systems include a TDS controller to add back some minerals for taste.
What TDS Means for Your Cleaning Products
A cleaning product's effectiveness against limescale depends on the hardness of your water. A product that works well at 200 ppm TDS may struggle at 500 ppm. This is why The Natural Company Tap Cleaner is formulated with higher citric acid concentration — to be effective even in India's hardest water conditions up to 600 ppm.
The Natural Company Tap Cleaner — effective in India's hardest water. Plant-based, non-toxic. Free shipping all over India.