Which type of water purifier is best for health?
The Answer Is Not as Simple as You Think
“RO water is bad for you.”
“Mineral water is the only healthy option.”
“Boiled water is safest.”
Everyone has an opinion. But what does the science actually say?
The truth is, the healthiest water is water that is free from harmful contaminants but still contains beneficial minerals – or has them added back.
No single purifier fits every home. The best choice depends on what is in your water, your health status, and your taste preferences.
This guide cuts through the myths and gives you the evidence-based answer.
The Two Key Principles of Healthy Drinking Water
Principle 1: Remove Harmful Contaminants
Water should be free from:
- Bacteria, viruses, parasites (cause disease)
- Heavy metals (lead, arsenic, mercury – cause long-term health damage)
- Chemicals (pesticides, nitrates, fluoride in excess)
- Microplastics (emerging concern)
Health impact: These contaminants cause everything from acute diarrhoea to cancer and developmental issues.
Principle 2: Preserve or Restore Beneficial Minerals
Water naturally contains healthy minerals:
| Mineral | Health benefit | Found in |
|---|---|---|
| Calcium | Bone health, heart function | Borehole water, mineral water |
| Magnesium | Muscle function, sleep, heart health | Borehole water, mineral water |
| Potassium | Blood pressure regulation | Some natural waters |
| Sodium (in balance) | Nerve function | Very small amounts in most water |
Health impact: These minerals are essential. But you also get them from food. The debate is whether water is a significant source.
GET IN TOUCH
Schedule a Visit
The Main Water Purifier Technologies – And Their Health Impact
1. Boiling
What it removes: Bacteria, viruses, parasites (100% effective for biological).
What it does NOT remove: Heavy metals, chemicals, TDS, microplastics.
Mineral content: Preserves minerals (concentrates them slightly).
Taste: Flat (oxygen removed).
Health verdict: Excellent for emergencies. Not for daily use (energy intensive, doesn’t remove chemicals). Safe if you already have clean source water.
Best for: Emergency situations, very small households.
Not for: Homes with borehole water containing heavy metals or high TDS.
2. Carbon Filtration
What it removes: Chlorine, bad tastes, odours, some sediment, some chemicals.
What it does NOT remove: Bacteria, viruses, parasites, heavy metals, TDS.
Mineral content: Preserves minerals.
Taste: Great (chlorine removed, minerals remain).
Health verdict: Healthy for city water that is already microbiologically safe and low in metals. Does not protect against disease.
Best for: Nairobi city water homes where the only complaint is taste.
Not for: Borehole water or homes with known heavy metal contamination.
3. Ultrafiltration (UF)
What it removes: Bacteria, viruses, parasites, sediment (pore size 0.01 microns).
What it does NOT remove: Heavy metals, TDS, chemicals, microplastics.
Mineral content: Preserves minerals.
Taste: Natural (minerals remain).
Health verdict: Healthy for low TDS borehole water with biological contamination. Leaves minerals intact. Does not remove heavy metals.
Best for: Homes with good water quality (low TDS) that only need biological protection.
Not for: Homes with high TDS or heavy metals.
4. Reverse Osmosis (RO)
What it removes: 99% of contaminants – bacteria, viruses, parasites, heavy metals, TDS, fluoride, nitrates, microplastics, salt.
What it does NOT remove: Nothing significant – but it also removes beneficial minerals.
Mineral content: Removes 90–95% of calcium, magnesium, potassium.
Taste: Very pure, but can taste “flat” to some people.
Health verdict: Most protective for contaminated water (heavy metals, high TDS, bacteria). Ideal for borehole water with multiple contaminants.
The “mineral debate”:
| Argument against RO | Counter-argument |
|---|---|
| RO removes healthy minerals | Most minerals come from food, not water. A balanced diet provides enough. |
| RO water is “empty” water | It is simply pure water. Many people drink it without issue for years. |
| Long-term RO water may cause mineral deficiencies | No strong evidence. The body adapts. |
The solution for mineral concerns: Many modern RO systems include a remineralisation filter – adding back calcium, magnesium, and potassium after purification. This gives you the best of both worlds: contaminant-free water with healthy minerals.
Health verdict (with remineralisation): Optimal. Removes 99% of contaminants while adding back essential minerals.
Best for: Homes with borehole water, high TDS, heavy metals, or wanting the purest drinking water.
Not for: Homes with already-pure, low-TDS city water (overkill).
5. UV Treatment
What it removes (neutralises): Bacteria, viruses, parasites (99.99% inactivation).
What it does NOT remove: Heavy metals, TDS, chemicals, microplastics, taste issues.
Mineral content: Preserves minerals.
Taste: Natural.
Health verdict: Excellent for biological protection while keeping minerals intact. Does nothing for chemical contamination.
Best for: Homes with low TDS water that already tastes good but has bacterial contamination.
Not for: Homes with high TDS or heavy metals.
6. Water Softeners
What it removes: Calcium and magnesium (hardness minerals).
What it does NOT remove: Bacteria, viruses, heavy metals, TDS, chemicals.
Mineral content: Removes healthy calcium and magnesium (the ones you want).
Taste: Soft water tastes different – some like it, some miss the minerals.
Health verdict: Softeners are not for health – they are for plumbing protection. They remove minerals your body needs. But you can get them from food. Not a health purifier.
Best for: Homes with hard water (scale damage). Always pair with a drinking water system (RO or carbon) for consumption.
Not for: Improving drinking water health.
The Healthiest Water Purifier – By Scenario
| Your water situation | Healthiest purifier | Why |
|---|---|---|
| Nairobi city water (low TDS, safe bacteria, chlorine taste) | Carbon filter | Removes chlorine, preserves minerals, improves taste. |
| Borehole water, low TDS, bacteria present | UV + sediment filter OR UF | Removes germs, preserves minerals. |
| Borehole water, high TDS (>200 ppm) | Reverse osmosis machine (with remineralisation if possible) | Removes heavy metals, salt, and dissolved solids. |
| Borehole water, high TDS + bacteria | Reverse osmosis machine (with remineralisation) | Removes everything. |
| Borehole water, hard (scale) + bacteria | Softener + UV (for whole house) + RO (for drinking) | Softener protects pipes; RO protects drinking health. |
| Old plumbing, possible lead | Reverse osmosis machine (lead removal is critical) | Boiling/UV do NOT remove lead. |
| Want bottled-water quality at home | Reverse osmosis machine | Closest to commercially purified water. |
| Renting, cannot install under-sink | Countertop RO or gravity filter | Portable, still removes contaminants. |
Addressing the “RO Water Is Bad for You” Myth
You have probably heard that RO water leaches minerals from your body. This is not supported by science.
The facts:
- Your body does not rely on water as a primary mineral source. Food provides the vast majority of calcium, magnesium, and potassium.
- Many people worldwide drink low-mineral water (rainwater, distilled water, softened water) without health issues.
- The World Health Organization (WHO) notes that demineralised water is safe for human consumption, though it recommends remineralisation for long-term use.
- The solution: If you are concerned, add a remineralisation stage to your RO system.
Bottom line: For contaminated water, RO is the healthiest choice because it removes harmful contaminants. For pristine water, it is overkill.
Beyond Homes: Schools, Institutions, and NGOs
For primary and secondary schools: A reverse osmosis machine or UV system scaled to handle hundreds of litres per day. House of Maji has installed systems in 15+ schools.
For boarding schools: A whole house water purification approach, treating water at the main entry point before it reaches dormitories, kitchens, and classrooms.
For universities and colleges: Campus-scale water systems that serve thousands of students daily.
For children’s homes and orphanages: Residential care requires the same reliability as a home – but at larger scale. A reverse osmosis machine sized for 50–200 people.
For NGOs serving remote communities: Containerised reverse osmosis machines powered by solar or generators.
For daycares and kindergartens: Small reverse osmosis machines or UV systems protect the most vulnerable children.
Why House of Maji Is the Best Water Treatment Company for Your Health
1. They Start with Certified Water Analysis – No Guessing
House of Maji begins every project with certified water analysis – scientific testing of physical, chemical, and microbiological properties. They will tell you exactly what is in your water – and what you need to remove for health.
2. They Offer Systems That Can Remineralise
For health-conscious customers, House of Maji supplies reverse osmosis machines with remineralisation filters – adding back calcium, magnesium, and potassium after purification. You get the purity of RO with the taste and mineral benefits of natural water.
3. They Have Installed Systems in 97+ Homes
Our website shows 97 homes as a client category. They understand Kenyan water challenges and Kenyan health concerns.