Why Your Water Source Matters
The right water treatment system — and the right RO membrane — depends heavily on your source water. Indian homes typically get water from two main sources: municipal (corporation) supply and borewell (groundwater). These have fundamentally different quality profiles.
Municipal Water
Municipal water is sourced from rivers, reservoirs, or lakes, treated at a central facility, and distributed through pipes.
Typical characteristics:
- TDS: 100–500 ppm in most Indian cities
- Contains chlorine (added for disinfection)
- May contain chloramines, disinfection byproducts
- Risk of contamination from aging pipe infrastructure
- Generally lower in heavy metals than borewell water (but not always)
- Quality varies significantly by city and even by area
Treatment recommendation: A standard 3–5 stage RO system with sediment and activated carbon pre-filters is typically sufficient. The carbon pre-filter is especially important to remove chlorine, which would otherwise degrade the RO membrane.
Borewell / Groundwater
Borewell water is pumped from underground aquifers. Its quality is highly location-dependent and influenced by local geology.
Typical characteristics:
- TDS: 500–3000+ ppm (highly variable)
- Often contains elevated calcium, magnesium (hard water)
- May contain iron, fluoride, arsenic, nitrates (geology-dependent)
- No chlorine (but may contain bacteria)
- Generally higher TDS than municipal water
Treatment recommendation: RO is strongly recommended. High iron content requires an iron pre-filter before the sediment stage. Very high TDS (above 1500 ppm) may benefit from a 100 GPD membrane for adequate throughput.
Comparison at a Glance
| Parameter | Municipal Water | Borewell Water |
|-----------|----------------|----------------|
| Typical TDS | 100–500 ppm | 500–3000+ ppm |
| Chlorine | Present | Absent |
| Heavy metals | Lower risk | Location-dependent |
| Iron | Rare | Common |
| Fluoride | Trace | Often higher |
| Bacteria | Low (treated) | Risk without treatment |
The Bottom Line
Both sources benefit from RO treatment in most Indian conditions. The key difference is:
- **Municipal water:** Focus on chlorine removal (carbon pre-filter is critical) and moderate TDS reduction
- **Borewell water:** Focus on TDS reduction, iron removal (if present), and consider a higher-capacity membrane if TDS is above 1500 ppm
When in doubt, test your water. A basic water test kit or TDS meter costs under ₹500 and gives you a starting point for understanding your source water quality.