Water Quality
Commercial RO Systems: 25 to 500 LPH for Offices and Institutions
A commercial RO system is a different class of equipment from a domestic purifier, not simply a bigger one. Stainless-steel construction instead of moulded plastic, industrial spiral-wound membranes in FRP pressure vessels, a dedicated pre-treatment train sized to your feed water, and control logic designed for continuous duty rather than twenty litres a day.
That distinction is the most expensive lesson in this category. Put a domestic unit in a forty-person office pantry and it runs almost continuously, exhausts its consumables in a third of their rated life, and is usually dead within eighteen months — and many warranties exclude commercial use in any case. The per-litre cost of a correctly specified commercial system is substantially lower than the per-litre cost of replacing domestic units.
Sizing by headcount
| People served | Daily drinking demand | Suggested plant | Suggested storage |
|---|---|---|---|
| Up to 15 | 50 – 60 L | A good domestic RO is genuinely adequate | 9 L tank |
| 15 – 30 | 60 – 120 L | 25 LPH | 200 L |
| 30 – 60 | 120 – 240 L | 50 LPH | 300 – 500 L |
| 60 – 120 | 240 – 480 L | 100 LPH | 500 – 1,000 L |
| 120 – 300 | 480 – 1,200 L | 250 LPH | 1,000 – 2,000 L |
| 300 – 800 | 1,200 – 3,200 L | 500 LPH | 2,000 – 3,000 L |
Tip
What makes a system genuinely commercial
- Construction — SS-304 chassis and piping, rated for continuous duty and washdown. SS-316 where chlorides are aggressive.
- Pressure vessels — industrial FRP housings with replaceable spiral-wound membranes, not sealed cartridges.
- Pre-treatment — dedicated multigrade sand and activated carbon vessels sized to feed quality, plus antiscalant dosing on hard water.
- Controls — HPS (high pressure sensor) with auto shut-off, dry-run protection, low/high pressure cut-offs, timed membrane flushing and level-based auto start-stop.
- Serviceability — every component individually replaceable, so a pump failure is a pump replacement rather than a new machine.
- Integration — plug-and-play compatibility with external storage tanks, water coolers and chillers.
Indicative pricing and AMC
Within each band, feed-water quality is the biggest variable, because it determines the size of the pre-treatment train. Two buyers ordering the same capacity can legitimately receive quotations 60% apart — one on 300 ppm municipal supply, the other on 1,800 ppm ferrous borewell water needing softening and antiscalant dosing.
This is why no credible supplier quotes a firm price without a water analysis, and why a suspiciously cheap quotation usually means an undersized pre-treatment train that you will pay for later in membrane replacements.
| Capacity | Indicative capex | Typical annual AMC | Power |
|---|---|---|---|
| 25 LPH | ₹25,000 – ₹45,000 | ₹3,000 – ₹6,000 | 0.5 HP, 1-phase |
| 50 LPH | ₹45,000 – ₹75,000 | ₹5,000 – ₹9,000 | 1 HP, 1-phase |
| 100 LPH | ₹75,000 – ₹1,50,000 | ₹8,000 – ₹20,000 | 1–2 HP, 1-phase |
| 250 LPH | ₹1,50,000 – ₹3,00,000 | ₹18,000 – ₹40,000 | 2–3 HP |
| 500 LPH | ₹3,00,000 – ₹6,00,000 | ₹35,000 – ₹80,000 | 3–5 HP, 3-phase |
What to check in a commercial quotation
- Is the pre-treatment train itemised, with vessel sizes and media quantities stated?
- Are membrane make, model and quantity specified, or just 'RO membrane'?
- Is pump make, rating and motor efficiency class given?
- What output quality is guaranteed, at what feed condition, and is there a performance test at handover?
- What exactly does the warranty cover, stated separately for membranes, pump, vessels and instrumentation?
- Are installation, commissioning and operator training included or extra?
- Are AMC terms and response times quoted alongside, so you can compare five-year cost rather than purchase price?