Total Dissolved Solids (TDS) refers to the combined content of all inorganic and organic substances contained in a liquid. In water purification systems, particularly Reverse Osmosis (RO) plants, controlling and reducing TDS is crucial for ensuring water quality and safety for consumption. High TDS levels can impact the taste, odor, and appearance of water and may also pose health risks over prolonged exposure.
This guide will take you through the practical and technical methods of reducing TDS in RO plants, including understanding the causes, optimizing system components, maintenance tips, and advanced solutions.
🔍 What Is TDS and Why It Matters
TDS includes minerals, salts, metals, and ions dissolved in water. Measured in parts per million (PPM), TDS indicates how much of these substances are present. Common components include:
- Calcium
- Magnesium
- Sodium
- Chlorides
- Sulfates
- Bicarbonates
- Organic matter
Ideal TDS for Drinking Water: According to WHO and BIS standards, TDS levels should be:
- Below 300 PPM: Excellent
- 300–600 PPM: Good
- 600–900 PPM: Fair
- 900–1200 PPM: Poor
- Above 1200 PPM: Unacceptable
⚖️ Causes of High TDS in RO Output
- Faulty RO Membrane
- Improper Pressure Settings
- Clogged Pre-Filters or Post-Filters
- Poor Water Source Quality
- System Bypass or Leakage
- TDS Controller Not Working
Identifying the root cause is the first step toward reducing TDS effectively.
💪 Effective Methods to Reduce TDS in RO Plant
1. Check and Replace the RO Membrane
The RO membrane is the core component that filters out 95% to 98% of TDS. Over time, the membrane can degrade and lose its efficiency.
- Replace every 12–18 months (depending on usage and water quality)
- Check the rejection rate using a TDS meter
2. Optimize Water Pressure
RO systems work best at 50-100 psi. Low pressure affects membrane performance.
- Use a pressure booster pump if needed
- Regularly inspect the pressure gauge
3. Install a TDS Controller
TDS controllers allow you to retain essential minerals by mixing filtered and unfiltered water.
- Calibrate the TDS controller for optimal balance
- Avoid over-adjustment to maintain health standards
4. Replace Pre and Post Filters
Sediment and carbon filters protect the RO membrane by removing larger particles and chlorine.
- Replace sediment filters every 6 months
- Replace carbon filters every 6–12 months
5. Regular Flushing and Cleaning
Fouling and scaling can block membranes and pipes.
- Perform chemical cleaning every 6 months
- Use RO membrane cleaning solutions
- Flush the system regularly to remove contaminants
6. Use Deionization (DI) Units
DI filters polish the water after RO to remove residual TDS.
- Ideal for labs, aquariums, and specialized industries
- Not commonly used for domestic systems
7. Install a Double-Stage RO System
In high-TDS areas, using a second RO stage can drastically lower TDS.
- First RO reduces TDS from source water
- Second RO polishes the output water
8. Use Anti-Scalant Dosing System
In industrial RO plants, anti-scalants prevent scale build-up.
- Improves membrane life
- Ensures continuous low TDS output
⚖️ TDS Reduction Troubleshooting Checklist
| Issue | Possible Cause | Solution |
|---|---|---|
| High TDS | Old RO Membrane | Replace membrane |
| Low Pressure | Weak pump or valve | Install booster pump |
| TDS Fluctuation | Faulty controller | Re-calibrate controller |
| High Output TDS | Bypass valve open | Close the bypass |
| Slow Flow | Clogged filters | Clean or replace filters |
🌐 Advanced Technologies for TDS Reduction
a) Nanofiltration (NF)
Filters smaller particles than RO but retains some minerals. Useful for soft water areas.
b) Electrodeionization (EDI)
Combines ion exchange and electricity to purify water.
- Common in pharmaceuticals
- Delivers ultra-pure water with zero TDS
c) Ultrafiltration (UF)
Works in conjunction with RO to extend membrane life by removing suspended solids.
🚗 RO Service Point (ROSP) TDS Management Solutions
RO Service Point (ROSP) is a trusted name in manufacturing and servicing RO plants across Delhi/NCR including:
Delhi, Noida, Greater Noida, Ghaziabad, Gurugram, Faridabad, Rohini, Dwarka, Laxmi Nagar, Preet Vihar, Mayur Vihar, Badarpur, Okhla, Jaitpur, and more.
We offer:
- Custom RO plants from 5 LPH to 50,000 LPH
- TDS management and AMC packages
- Water testing and onsite diagnosis
- Replacement of membranes, filters, and pumps
Visit www.roservicepoint.com or call 9560654995 for consultation.
📊 How to Monitor TDS at Home
Use a TDS meter to check input and output levels:
- Turn on the meter and dip it in water
- Wait for stable reading
- Compare with ideal range (50–100 PPM for drinking)
Keep records monthly to track performance and know when to service your system.
📆 Maintenance Schedule for TDS Control
| Component | Frequency |
| Sediment Filter | Every 6 months |
| Carbon Filter | Every 6-12 months |
| RO Membrane | Every 12-18 months |
| System Sanitization | Every 6 months |
| TDS Controller Check | Every 3 months |
💧 TDS Levels and Their Significance for Drinking Water:
| TDS Level (mg/L or ppm) | Water Quality | Suitability |
|---|---|---|
| 0 – 50 | Very Low | Not ideal – lacks essential minerals |
| 50 – 150 | Excellent | Ideal for drinking (with essential salts) |
| 150 – 300 | Good | Acceptable for regular consumption |
| 300 – 500 | Fair | Still safe but may affect taste |
| 500 – 1000 | Poor | Not recommended for drinking |
| Above 1000 | Unacceptable | May cause health issues |
✅ Safe TDS Range for Drinking Water (as per BIS standards in India):
- Recommended Limit: 500 mg/L
- Maximum Permissible Limit (if no alternative source): 2000 mg/L
Ideal TDS for RO Water: Between 50–150 ppm – ensures purity while retaining essential minerals like calcium, magnesium, and potassium.
⚠️ High TDS Risks:
- Salty or bitter taste
- Scale buildup in appliances
- May contain harmful heavy metals or contaminants
⚠️ Very Low TDS Risks:
- De-mineralized water may lead to mineral deficiencies
✅ Is 25 TDS Safe For Drinking Water?
Yes, 25 TDS is safe from a contaminant perspective — the water is very pure and free from harmful substances.
⚠️ But Is It Ideal? Not Really. Here’s Why:
- Very low in essential minerals like calcium, magnesium, potassium, and sodium.
- Can lead to mineral deficiency over time if consumed regularly.
- Tastes flat or bland because of the lack of natural salts.
🧪 WHO & BIS Guidelines:
- The World Health Organization (WHO) and Bureau of Indian Standards (BIS) recommend:
- Ideal TDS: 50–150 ppm
- Acceptable upper limit: 500 ppm
Clean water is not a luxury, it’s a necessity. Keep your RO healthy, and your water pure!
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