What is the quality of water for drinking? This is a question about brackish water. The answer is no. Brackish water cannot be used for drinking unless it has been properly treated with certified water purification technology. If you drink brackish water, it can cause dehydration, kidney stress, sodium poisoning and serious health problems. The World Health Organization sets a drinking water limit of 500 mg/L. Brackish water is above this limit.
In this guide we will cover everything you need to know about drinking water safely. We will look at its health impact, compare water to drinking water and discuss the best filtration systems for brackish water. We will also look at reverse osmosis specifications. How to make brackish water drinkable. Brackish water is not safe to drink. Brackish water needs treatment. Brackish water can cause health problems. Brackish water has sodium levels. Brackish water requires filtration.
To learn more about water, its sources and distribution, read our Pillar Guide.
Brackish Water Explained | Sources & Treatment Methods 2026
What Is Brackish Water? A Quick Look
Brackish water is a mix of salt and water. It has a higher salt level than fresh water but not as salty as seawater. Brackish water is found in places like estuaries, where rivers meet the sea, and in areas of tidal rivers and some inland basins. The saltiness of water is measured by its total dissolved solids, or TDS. Brackish water is common in coastal aquifers.
| Water Type | TDS (mg/L) | Potability |
|---|---|---|
| Pure Distilled Water | < 10 | Safe |
| WHO Drinking Standard | < 500 | Safe |
| Acceptable Limit | < 1,000 | Marginal |
| Brackish Water (Low) | 1,000 – 3,000 | Unsafe |
| Brackish Water (Mid) | 3,000 – 7,000 | Harmful |
| Brackish Water (High) | 7,000 – 10,000 | Toxic Risk |
| Seawater | 30,000 – 40,000 | Toxic |
Can You Drink Brackish Water? The Science
Short answer: No. You cannot drink water without proper treatment.
Brackish water is not good for you. The human kidney can get rid of salt in urine at a certain level, about 2 per cent. If you drink water with a lot of salt, like 3,000 to 5,000 milligrams per litre, your kidneys have to use more water to get rid of the extra salt than you actually drank. This means you will lose more water than you gain, and that is not good.
The Osmotic Paradox
When you drink water, it causes dehydration. Your body takes water from your cells to dilute the salt and that causes your cells to lose water even if you are drinking water. The more salt in the water the worse it gets.
What Does WHO Say?
The World Health Organization says that the most salt you should have in drinking water is 600 milligrams per litre. If the water has more than 1,000 milligrams per liter it is not good for drinking. You have to treat it before you can drink it.
What About Boiling Brackish Water?
Boiling brackish water does not make it safe to drink. Boiling gets rid of some things like bacteria and viruses, but it does not get rid of the salt. In fact, boiling makes the water even saltier because some of the water evaporates. The only ways to get rid of the salt are to use a filter or to distil the water.
Survival Warning
If you are in a situation and you drink brackish water from a river or a well near the ocean, it can make you even more dehydrated. If you are already thirsty and you drink water with a lot of salt, you will get worse in just a few hours.
Health Effects of Drinking Brackish Water
Drinking brackish water can make you feel sick and it can even hurt your organs really badly. It depends on how much salt’s in the water and how long you drink it. Brackish water is not good for you. You should not drink it without treating it first. Drinking water can cause a lot of health problems so you have to be careful.
| Health Effect | Mechanism | Onset | Severity |
|---|---|---|---|
| Nausea / Vomiting | High sodium irritates GI mucosa | 0.5 – 2 hrs | Moderate |
| Osmotic Dehydration | Net fluid loss via renal excretion | 2 – 6 hrs | High |
| Hypernatremia | Na⁺ overload disrupts cell fluid balance | 4 – 12 hrs | Severe |
| High Blood Pressure | Sodium retention increases blood pressure | Cumulative | Moderate |
| Kidney Stress | Excess TDS overloads glomerular filtration | Chronic | High |
| Neurological Effects | Cellular dehydration in brain tissue | 8 – 24 hrs | Severe |
| Organ Failure (extreme) | Multi-system ionic imbalance | 24 – 72 hrs | Critical |
Vulnerable Populations
The people who are most at risk are children, elderly people, pregnant women and people with kidney or heart problems. These people, children, can get very sick if they drink water that has a lot of extra stuff in it like salt. If kids drink water with over 2,000 mg/L Total Dissolved Solids it can cause a problem called ‘hypernatraemia’ even if it is just for a short time. Vulnerable populations, like children and people with kidney problems, need to be careful about the water they drink.
Brackish Water vs. Drinking Water: TDS Comparison
| Parameter | Untreated Brackish Water | WHO Drinking Water Standard |
|---|---|---|
| TDS | 1,000 – 10,000 mg/L | < 500 mg/L |
| Sodium | 500 – 4,000 mg/L | < 200 mg/L |
| Chloride | 600 – 5,000 mg/L | < 250 mg/L |
| Sulfate | Often elevated | < 250 mg/L |
| Conductivity | 1.5 – 15 mS/cm | < 0.8 mS/cm |
| Turbidity | Variable | < 1 NTU |
| Taste | Saline, bitter, metallic | Neutral, acceptable |
| Potability | NOT SAFE | SAFE |
Safe drinking water needs the amount of stuff in the water to be a lot lower. We are talking about a reduction in Total Dissolved Solids when we start with water that is already kind of salty. To make the water safe to drink we need to remove a lot of the stuff, which means we have to use special membranes or heat to clean the water. Just using a filter is not enough to make the water safe.
Brackish Water Filtration Systems
The problem with Brackish Water is not getting rid of the dirt and particles in the water but getting rid of the dissolved ions, like sodium and chloride and sulfate and calcium and magnesium and all the other bad salts that are dissolved in the Brackish Water.
| Technology | TDS Removal | Cost | Suitable for BW? |
|---|---|---|---|
| Sediment Filter (5 micron) | < 1% | Low | No |
| Activated Carbon Filter | < 5% | Low | No |
| Ion Exchange (Softener) | Partial Ca/Mg only | Medium | Partial |
| Nanofiltration (NF) | 50 – 70% | Medium-High | Partial |
| Brackish Water RO (BWRO) | 95 – 99% | Medium | Best Choice |
| Electrodialysis (EDR) | 80 – 95% | High | Yes |
| Multi-Stage Flash (MSF) | > 99% | Very High | Industrial Only |
Expert Recommendation:
For both home and business water treatment Brackish Water Reverse Osmosis delivers the best balance of salt removal, energy savings and affordability. It always meets the World Health Organization’s standard of 500 milligrams per liter or less of dissolved solids for drinking water.
Brackish Water Reverse Osmosis: Technical Deep Dive
Brackish Water Reverse Osmosis uses membranes to remove dissolved salts from water under pressure. Brackish Water Reverse Osmosis works at lower pressures than Seawater Reverse Osmosis making Brackish Water Reverse Osmosis more energy-efficient and cost-effective.
Key Technical Specifications
| Parameter | BWRO Value |
|---|---|
| Operating Pressure | 250 – 400 psi |
| Salt Rejection Rate | 95 – 99% |
| Membrane Pore Size | 0.0001 micron |
| Water Recovery Rate | 60 – 80% |
| Product Water TDS | < 500 mg/L |
| Energy Consumption | 0.5 – 1.5 kWh/m³ |
BWRO System Components
| Component | Function | Specification |
|---|---|---|
| Pre-Filter (Multimedia) | Removes suspended solids, turbidity | 5 – 20 micron |
| Activated Carbon Filter | Removes chlorine, organics, odor | Granular or block carbon |
| Antiscalant Dosing | Prevents mineral scaling on membranes | Phosphonate-based chemicals |
| High-Pressure Pump | Generates RO operating pressure | 250 – 400 psi |
| BWRO Membrane Elements | Core desalination via osmotic pressure | 8″ × 40″ spiral wound TFC |
| Pressure Vessels | Houses 4–7 membrane elements in series | FRP or stainless steel |
| Post-RO Remineralization | Restores beneficial minerals Ca and Mg | Calcite/dolomite media |
| UV Sterilizer | Final biological disinfection | 254 nm, min 30 mJ/cm² |
| Product Tank & Pump | Storage and distribution of treated water | Food-grade HDPE or stainless |
BWRO vs. SWRO: Key Differences
| Parameter | BWRO | SWRO |
|---|---|---|
| Feed Water TDS | 1,000 – 10,000 mg/L | 30,000 – 45,000 mg/L |
| Operating Pressure | 250 – 400 psi | 800 – 1,200 psi |
| Energy Consumption | 0.5 – 1.5 kWh/m³ | 3 – 5 kWh/m³ |
| Recovery Rate | 60 – 80% | 35 – 50% |
| Capital Cost | Moderate | Very High |
Methods to Desalinate Brackish Water
Electrodialysis Reversal (EDR)
EDR uses membranes and electricity to move dissolved ions from the feed stream into a concentrate stream. It works well for water with low to mid Total Dissolved Solids (TDS). 1,000 To 5,000 milligrams per liter. EDR can handle some suspended solids better than Reverse Osmosis (RO) membranes.
Capacitive Deionization (CDI)
CDI is a technology that uses carbon electrodes to attract and hold dissolved ions. It works best for water with TDS below 3,000 milligrams per liter. CDI is being tested for use in areas without a grid because it requires voltage. 1.2 To 1.5 Volts Direct Current.
Brackish Water Desalination using Solar Power
In places like UAE, Pakistan and Saudi Arabia which get a lot of sunlight, solar-powered systems are being used. These systems use panels to drive pumps, which reduces energy costs by 60 to 80 percent compared to traditional grid-powered systems.
Forward Osmosis (FO) A New Technology
FO uses the pressure difference between brackish water and a concentrated solution to work. It needs little pressure and is currently being tested for use, with brackish water.
| Desalination Method | Best TDS Range | Energy | Commercial Status |
|---|---|---|---|
| BWRO | 1,000 – 10,000 mg/L | Low-Medium | Commercial |
| EDR | 1,000 – 5,000 mg/L | Medium | Commercial |
| CDI | 500 – 3,000 mg/L | Low | Emerging |
| Solar BWRO | 1,000 – 10,000 mg/L | Very Low | Commercial |
| Forward Osmosis | Any | Low | Pilot Stage |
Step-by-Step: How To Make Brackish Water Drinkable
Step 1: Raw Water Testing & TDS Analysis
Test the source water before designing any treatment system. Test TDS, pH, turbidity, hardness (Ca²⁺ + Mg²⁺), sodium, chloride, sulfate, iron, manganese and biological load. This influences the selection of membranes, pre-treatment and the size of the system.
Step 2: Pre-Treatment: Sediment & Carbon Filtration
Sediment filters the water with a 5 micron membrane to remove suspended particles and then passes the water through an activated carbon filter to remove chlorine, chloramines, VOCs and other organic fouling agents that would harm the RO membranes.
Step 3: is the chemical dosing of the antiscalant
Add antiscalant chemicals (phosphonate based or polymer blends) before the RO membranes. This will help to avoid the formation of scaling, which is the main reason for loss of performance and membrane fouling in brackish water systems, caused by calcium carbonate, calcium sulfate and barium sulfate.
Step 4: is “Brackish Water Reverse Osmosis (Core Treatment)
The pre-treated feed water is pressurized (250 – 400 psi) and fed through TFC spiral wound RO membranes. The membranes are capable of rejecting 95-99% of these salts and the product water has a dissolved solids content (DSC) of usually 50-300 mg/l, sending the salt concentrate to a dedicated discharge pipe.
Step 5: Post-RO Remineralization
Water treated by RO is almost pure without containing the necessary minerals. Use a dolomite or calcite remineralization filter to re-mineralize the permeate to add back calcium and magnesium to levels of about 50-100 mg/l, enhancing taste and adding health-giving minerals.
Step 6: pH Correction
The pH for RO product water is slightly acidic (5.5 – 6.5). Use lime dosing systems or CO₂ injection systems to adjust the pH to the WHO acceptable range (6.5 – 8.5).
The final barrier is the UV Disinfection (Step 7)
Run treated water through a UV disinfection system (254 nm with minimum dose of 30 mJ/cm2) to kill any remaining bacteria, viruses and protozoa. A low dose chlorination (0.2-0.5 mg/L residual) is included for the protection of the network for larger distribution systems.
Step 8: is Product Water Quality Verification
Conduct water quality tests on the finished product: TDS < 500 mg/L, pH 6.5-8.5, turbidity < 1 NTU, sodium < 200 mg/L, and no coliforms detected. For continuous compliance, install continuous inline TDS meters and have periodic lab testing.
For advanced RO systems, brackish water treatment plants, and water purification solutions, visit Water Treatment UAE for more information.
Quality Assurance
An effective design of a brackish water RO system produces WHO compliant drinking water with TDS < 300 mg/L, pH 7.0-8.0 and no detectable pathogens.
End Result: If we follow all these steps we can make brackish water clean and safe to drink. The water will have the right amount of minerals and will be free of any bad stuff. We can drink it. Know it is good for us. Brackish water treatment is a job but it is worth it to have clean drinking water. Brackish water is not good to drink when it is not treated. When we treat it it becomes good water.
Need brackish water treatment solutions, BWRO systems, or water purification support? Visit Water Treatment UAE to explore treatment technologies and expert guidance.
Conclusion
Brackish water can NOT be used without treatment. It has a very high TDS level (1000 – 10,000 mg/l), which leads to osmotic dehydration, sodium toxicity, kidney damage and in extreme cases to kidney organ failure. The difference between brackish water and potable water is not apparent to the naked eye and can be particularly hazardous in areas with limited water supplies.
Fortunately, brackish water can be effectively treated to provide potable water, as per WHO standards at reasonable energy cost and at relatively lower energy input as compared to seawater desalination, using the appropriate treatment technology in general, Brackish Water Reverse Osmosis (BWRO).
More Information
To learn more about the nature of brackish water, how it is formed, where it is found, in what ways it is formed around the world, and its ecological significance, read our full Pillar
Guide:
Brackish Water Explained | Sources & Treatment Methods 2026 —watertreatmentuae.com
FAQs
Q1. Can you drink brackish water?
mg/L TDS, far exceeding the WHO safe limit of 500 mg/L. Drinking it untreated causes osmotic dehydration, hypernatremia, and kidney stress. It must be treated via reverse osmosis or desalination before consumption.
Q2. What are the health effects of drinking brackish water?
water causes nausea, gastrointestinal upset, osmotic dehydration, hypernatremia (sodium poisoning), elevated blood pressure, kidney damage, neurological effects, and in extreme cases organ failure. Severity depends on TDS concentration and duration of exposure.
Q3. What is the best filtration system for brackish water?
Brackish Water Reverse Osmosis (BWRO) is the most effective and cost-efficient system, removing 95–99% of dissolved salts and producing water under 500 mg/L TDS — meeting WHO safe drinking water standards.
Q4. How to make brackish water drinkable?
Use a multi-stage treatment process: sediment pre-filter → activated carbon filter → antiscalant dosing → BWRO membranes (250–400 psi) → remineralization filter → pH correction → UV sterilization. This process reliably produces WHO-compliant drinking water
Q5. How to make brackish water drinkable?
Bathing with low-to-mid TDS brackish water (under 3,000 mg/L) is generally not harmful for healthy adults, though it may cause skin dryness and irritation with regular use.
Q6. How long do brackish water RO membranes last?
With proper pre-treatment and regular maintenance, BWRO membranes typically last 3–7 years. Regular CIP (Clean-In-Place) protocols extend membrane life significantly.
Q7. Can boiling make brackish water drinkable?
No. Boiling removes biological contaminants but does not remove dissolved salts. Boiling actually concentrates the TDS further as water evaporates, making brackish water more dangerous after boiling.
Q8. What is the difference between brackish water and drinking water?
water has TDS below 500 mg/L (WHO standard), while brackish water has TDS of 1,000–10,000 mg/L. Brackish water contains dangerous levels of sodium, chloride, and sulfate that human kidneys cannot safely process without industrial-grade treatment
