What is a safe water TDS level for drinking?
The question most Hyderabad households ask is simple: what water TDS level is safe for drinking? The Indian standard for drinking water, IS 10500 from the Bureau of Indian Standards, sets the acceptable limit for total dissolved solids (TDS) at 500 mg/L. It allows up to 2,000 mg/L as a permissible limit only where no alternate source is available. The acceptable pH range is 6.5 to 8.5.
TDS measures the total of dissolved minerals and salts, such as calcium, magnesium, sodium, chlorides, sulphates and bicarbonates. A high number tells you the water is mineral-heavy. It does not, by itself, tell you whether the water is safe.
Safe TDS and pH ranges at a glance
| Parameter | Acceptable (IS 10500) | Permissible if no alternate source | What it means |
|---|---|---|---|
| TDS | Up to 500 mg/L | Up to 2,000 mg/L | Above 500, taste worsens and scaling increases |
| pH | 6.5 to 8.5 | No relaxation | Below 6.5 is acidic and can corrode pipes; above 8.5 is alkaline and tastes soapy |
| Total hardness (as CaCO3) | Up to 200 mg/L | Up to 600 mg/L | Scale on taps, geysers and pipes |
| Chloride | Up to 250 mg/L | Up to 1,000 mg/L | Salty taste and corrosion |
| Fluoride | Up to 1.0 mg/L | Up to 1.5 mg/L | Excess affects teeth and bones over long exposure |
| Nitrate | Up to 45 mg/L | No relaxation | A concern for infants |
These are the figures commonly cited from IS 10500. Standards are revised from time to time, so check the current edition if you need exact figures for a legal or institutional purpose.
Reading your TDS number in practice
- Below about 50 mg/L: very low mineral content. Often seen after over-aggressive RO purification.
- 50 to 300 mg/L: generally comfortable for drinking and cooking.
- 300 to 500 mg/L: within the acceptable limit, though some people notice a mineral taste.
- 500 to 2,000 mg/L: above the acceptable limit; treatment such as RO is usually advisable if you have a choice.
- Above 2,000 mg/L: not suitable for drinking without treatment.
Hyderabad tap water versus borewell water
Hyderabad's piped municipal supply comes from reservoirs and river sources and is treated and chlorinated before distribution. TDS in treated supply is usually lower than in groundwater, but what reaches your tap also depends on pipe condition, sump and overhead tank hygiene, and whether supply mixes with other sources.
Borewell water is a different story. It reflects the local geology and can carry high hardness, TDS, fluoride or nitrate depending on where you are. Two borewells a few streets apart can give quite different readings, so never assume your neighbour's result applies to your building. Many apartments mix tanker, borewell and municipal supply in one sump, which makes testing the water at the actual tap more meaningful than testing at source.
How to test water quality at home
- Use a TDS meter for a quick reading. Rinse the probe, dip it in a clean glass of water and wait for the number to settle.
- Use pH strips or a pH meter for acidity or alkalinity. Meters need calibration to stay reliable.
- Test at several points: the kitchen tap, the RO outlet, and the sump or tank if accessible.
- Get a lab test if you suspect contamination, have infants at home, or are using borewell water as your main source.
What a TDS meter cannot tell you
A TDS meter measures conductivity, not safety. Water can read a low TDS and still contain bacteria. It can also read moderate TDS and carry lead, arsenic, fluoride or pesticides at unsafe levels. For microbial safety, a laboratory bacteriological test is the right tool. For fluoride, nitrate and metals, ask for a chemical analysis against the IS 10500 parameters.
Other parameters worth checking besides TDS and pH
TDS and pH are the quick numbers, but they leave out several things that matter for health and for the home itself.
- Hardness: hard water leaves white scale on taps, shower heads and geysers, and can shorten the life of appliances. A water softener or descaling routine helps.
- Chlorine residual: piped supply is usually chlorinated, and a small residual shows the water was disinfected. A strong chlorine smell can be reduced by letting water stand or by using an activated carbon filter.
- Iron: reddish stains on fixtures and a metallic taste suggest iron in the water.
- Microbial contamination: the biggest short-term health risk, especially after heavy rain or when tanks are dirty. Clean sumps and overhead tanks at regular intervals.
Is very low TDS water good for you?
RO systems remove most dissolved solids, which is helpful for hard borewell water. But running the output close to zero TDS strips minerals and flattens the taste. If your RO has a TDS controller or mineraliser, set it so the output lands in a comfortable range rather than at the lowest possible number. If your source is already below 300 mg/L, you may not need RO at all, and a basic filter or UV treatment may be more appropriate.
Water quality when buying or moving into a home
If you are buying a flat or villa, water is part of the home's livability. Ask the seller about the water source, check the sump and overhead tank for cleanliness, look for rust or scale on taps and geysers, and run a TDS and pH reading at the kitchen tap. Persistent scale deposits usually mean hard water, which shortens the life of geysers, washing machines and fixtures. A home inspection that includes plumbing and water checks surfaces these issues before you commit.
Check your water before you move in
Our engineers can include water-quality checks with a full home inspection. See the pricing page for packages or book an inspection and ask for water testing to be part of the visit. For regulatory or health decisions, always support readings with a recognised laboratory report.