What are the 12 diseases caused by water pollution?
Every Glass Could Be a Risk
You turn on the tap. The water looks clean. It might even taste fine.
But invisible threats could be flowing through your pipes – bacteria, viruses, parasites, and chemicals that cause devastating diseases.
Water pollution is not just an environmental issue. It is a health crisis that affects millions of Kenyans every year. From schools to hospitals to homes, contaminated water leads to illness, absenteeism, and even death.
This guide lists 12 diseases caused by water pollution – how you get them, what they do to your body, and most importantly, how to prevent them with proper water treatment systems.
How Water Pollution Causes Disease
Water becomes polluted through:
| Source of pollution | Contaminants introduced |
|---|---|
| Sewage and human waste | Bacteria, viruses, parasites (e.g., E. coli, cholera) |
| Agricultural runoff | Pesticides, nitrates, fertilisers |
| Industrial waste | Heavy metals (lead, arsenic, mercury), chemicals |
| Old plumbing | Lead, rust, sediment |
| Animal waste | Giardia, Cryptosporidium, E. coli |
| Poor sanitation at water sources | Faecal contamination |
When people drink, cook with, or even bathe in contaminated water, these pathogens enter the body – causing the diseases below.
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The 12 Diseases Caused by Water Pollution
1. Cholera
Cause: Bacteria (Vibrio cholerae) from sewage-contaminated water.
Symptoms: Severe watery diarrhoea (sometimes called “rice water stool”), vomiting, rapid dehydration.
At-risk groups: Children under 5, elderly, people in crowded settings (schools, refugee camps).
Prevention: Reverse osmosis machine, UV treatment, chlorination, or boiling.
Outbreaks in Kenya: Recurring outbreaks in informal settlements, coastal regions, and refugee camps.
2. Typhoid Fever
Cause: Bacteria (Salmonella typhi) from food or water contaminated with human waste.
Symptoms: Prolonged fever, headache, constipation or diarrhoea, rose-coloured spots on chest.
At-risk groups: Schools, boarding houses, families using untreated borehole water.
Prevention: Water treatment system (RO or UV), proper sanitation, vaccination (partial protection).
3. Dysentery (Amoebic and Bacillary)
Cause: Bacteria (Shigella) or amoeba (Entamoeba histolytica) in contaminated water.
Symptoms: Bloody diarrhoea, abdominal pain, fever, dehydration.
At-risk groups: Daycares, schools, institutions with poor hygiene.
Prevention: Reverse osmosis machine, UV treatment, boiling, handwashing.
4. Giardiasis (Beaver Fever)
Cause: Parasite (Giardia lamblia) from water contaminated by animal or human waste.
Symptoms: Explosive diarrhoea, greasy stools, gas, stomach cramps, nausea.
At-risk groups: Hikers (untreated streams), children in daycares, borehole users.
Note: Giardia is resistant to chlorine – needs filtration or RO.
Prevention: Reverse osmosis machine or ultrafiltration (UF). Boiling also works.
5. Cryptosporidiosis (Crypto)
Cause: Parasite (Cryptosporidium parvum) highly resistant to chlorine.
Symptoms: Watery diarrhoea, stomach cramps, dehydration, fever.
At-risk groups: Children, people with weakened immune systems (HIV, cancer patients).
Note: Extremely resistant – standard chlorination does NOT kill it.
Prevention: Reverse osmosis machine or boiling. UV treatment also effective.
6. Hepatitis A
Cause: Virus (Hepatitis A) from faecally contaminated water or food.
Symptoms: Fever, fatigue, loss of appetite, nausea, dark urine, jaundice (yellowing of skin).
At-risk groups: Schools, institutions, areas with poor sanitation.
Prevention: Water treatment system (RO, UV, or boiling). Vaccine available.
7. Polio (Poliomyelitis)
Cause: Poliovirus from contaminated water (rare in Kenya due to vaccination, but still a risk in some areas).
Symptoms: Fever, fatigue, headache, vomiting, stiff neck, paralysis (in severe cases).
At-risk groups: Unvaccinated children.
Prevention: Vaccination (primary) + reverse osmosis machine or UV for water safety.
8. Leptospirosis (Weil’s Disease)
Cause: Bacteria (Leptospira) from water contaminated with animal urine (rats, cattle, pigs).
Symptoms: High fever, muscle pain, red eyes, headache, liver and kidney damage.
At-risk groups: Flood-prone areas, farmers, people using surface water.
Prevention: Water treatment system (RO or UV), rodent control, avoid floodwater.
9. Campylobacteriosis
Cause: Bacteria (Campylobacter jejuni) from animal waste in water.
Symptoms: Diarrhoea (sometimes bloody), fever, stomach cramps, nausea.
At-risk groups: Children under 5, schools, rural borehole users.
Prevention: Reverse osmosis machine, UV treatment, or boiling.
10. E. Coli Infection
Cause: Specific strains of E. coli bacteria (e.g., O157:H7) from faecal contamination.
Symptoms: Severe diarrhoea (often bloody), abdominal cramps, vomiting. Can lead to kidney failure in children.
At-risk groups: Daycares, schools, elderly, anyone drinking untreated borehole water.
Prevention: Water treatment system (RO or UV). Boiling also effective.
11. Arsenic Poisoning (Arsenicosis) – Chemical Contamination
Cause: Natural arsenic in groundwater (not a living organism, but a chemical pollutant).
Symptoms: Skin lesions, skin cancer, cardiovascular disease, developmental issues in children.
At-risk groups: Borehole users in volcanic or mineral-rich areas (parts of Rift Valley).
Note: Boiling does NOT remove arsenic. Chlorine does NOT remove arsenic.
Prevention: Reverse osmosis machine (99% removal). Also activated alumina or iron filters.
12. Lead Poisoning – Chemical Contamination
Cause: Lead from old plumbing pipes, lead solder, or industrial pollution.
Symptoms (children): Lowered IQ, behavioural issues, anaemia, developmental delays.
Symptoms (adults): High blood pressure, joint pain, memory problems.
At-risk groups: Homes and schools with plumbing from before the 1990s (lead solder was common).
Note: Boiling does NOT remove lead. Chlorine does NOT remove lead.
Prevention: Reverse osmosis machine (99% removal). Also certified lead-removing carbon filters.
Quick Reference Table: 12 Diseases and Their Prevention
| Disease | Type | Water treatment that works |
|---|---|---|
| 1. Cholera | Bacteria | RO, UV, boiling, chlorination |
| 2. Typhoid | Bacteria | RO, UV, boiling, chlorination |
| 3. Dysentery | Bacteria/amoeba | RO, UV, boiling |
| 4. Giardiasis | Parasite | RO, UF, boiling (chlorine resistant) |
| 5. Cryptosporidiosis | Parasite | RO, boiling (highly chlorine resistant) |
| 6. Hepatitis A | Virus | RO, UV, boiling |
| 7. Polio | Virus | RO, UV, boiling |
| 8. Leptospirosis | Bacteria | RO, UV, boiling |
| 9. Campylobacteriosis | Bacteria | RO, UV, boiling |
| 10. E. coli infection | Bacteria | RO, UV, boiling |
| 11. Arsenic poisoning | Chemical | RO only (boiling/UV do nothing) |
| 12. Lead poisoning | Chemical | RO only (boiling/UV do nothing) |
Key takeaway: For biological contaminants (bacteria, viruses, parasites), reverse osmosis machines and UV systems work. For chemical contaminants (arsenic, lead), reverse osmosis is the only reliable home treatment.
Why Schools, Institutions, and NGOs Must Take Action
For primary and secondary schools:
- Waterborne diseases are among the leading causes of school absenteeism in Kenya.
- One outbreak can shut down a school for weeks.
- House of Maji has installed water treatment systems in 15+ schools.
For boarding schools:
- Students are on site 24/7. No “safe” tap at home.
- A whole house water purification system protects dormitories, kitchens, and classrooms.
For universities and colleges:
- Thousands of students, plus staff, plus visitors.
- Campus-scale water systems prevent widespread outbreaks.
For hospitals and clinics:
- Vulnerable patients cannot tolerate contaminated water.
- Sterilisation requires pure water – reverse osmosis is often the minimum standard.
For NGOs and humanitarian organisations:
- Serving displaced or vulnerable populations.
- A community-scale water treatment system can transform health outcomes.
For children’s homes and orphanages:
- Full-time residential care for vulnerable children.
- Water quality is a non-negotiable safeguarding issue.
For daycares and kindergartens:
- Small children have developing immune systems.
- Even mild diarrhoea is dangerous for toddlers.
For portable water refill businesses:
- Your reputation depends on producing safe water every single day.
- A commercial reverse osmosis machine is the standard.
The Prevention Solution: Water Treatment Systems That Work
The 12 diseases above are preventable. You do not need to live in fear of your tap water.
For biological contaminants (bacteria, viruses, parasites):
| Technology | Effectiveness | Best for |
|---|---|---|
| Reverse osmosis machine | 99%+ removal | High TDS, heavy metals, AND biological protection |
| UV treatment | 99.99% inactivation | Low TDS water with biological only |
| Boiling | 100% (but impractical for scale) | Emergency, small households |
| Chlorination | 99% (except Crypto/Giardia) | Large municipal systems |
For chemical contaminants (arsenic, lead, nitrates):
| Technology | Effectiveness |
|---|---|
| Reverse osmosis machine | 99% removal |
| Boiling | 0% |
| Chlorination | 0% |
| UV | 0% |
| Carbon filter | Partial (some lead, not arsenic) |
Conclusion: A reverse osmosis machine is the only home technology that removes both biological and chemical contaminants completely.
Why House of Maji Is the Best Water Treatment Company for Preventing Waterborne Diseases
1. They Start with Certified Water Analysis – Find the Hidden Threats
You cannot prevent what you have not measured. House of Maji begins every project with certified water analysis – scientific testing of physical, chemical, and microbiological properties. They will tell you exactly which of the 12 diseases you are at risk for.
2. They Design Systems That Remove or Neutralise Pathogens
House of Maji supplies reverse osmosis machines (which remove 99% of all contaminants) and UV systems (which neutralise 99.99% of bacteria and viruses). They will recommend the right water treatment system for your specific water quality.
3. They Have Installed Systems in 15+ Schools, 44+ Refill Businesses, and 97+ Homes
Our track record proves we know how to prevent waterborne diseases in Kenyan settings – from small homes to large institutions.