Main Causes Of Water Pollution & Contamination

Main Causes Of Water Pollution & Contamination

This is a short guide outlining the main causes of water pollution and contamination.

We’ve delineated between what might water pollution/contamination causes more relevant to developed countries, and also developing countries.

But, we’ve also included a full list of causes that can occur in any country.


Main Causes Of Water Pollution & Contamination In Developed Countries

  • Agriculture – runoff from fertilizer, pesticides and herbicides is responsible into groundwater and surface water. Nitrates (found in fertilizer) in particular can cause algal blooms in water. Phosphate run-off can also cause issues like eutrophication
  • Industry and factories – dumping or discharge of factory/industry chemicals and wastewater into freshwater sources
  • Transport – Fuel and oil run off from vehicles and roads into freshwater sources
  • Air Pollution – from vehicles and power plants. Air pollution causes issues like acid rain that rains back down into freshwater water sources and pollutes it



In the US specifically:

  • Nearly 40 percent of Americans rely on groundwater, pumped to the earth’s surface, for drinking water. For some in rural areas, it’s their only freshwater source. Groundwater gets polluted when contaminants—from pesticides and fertilizers to waste leached from landfills and septic systems—make their way into an aquifer, rendering it unsafe for human use. (
  • Surface water from freshwater sources … accounts for more than 60 percent of the water delivered to American homes. … nearly half of rivers and streams and more than one-third of lakes are polluted and unfit for swimming, fishing, and drinking. Nutrient pollution, which includes nitrates and phosphates, is the leading type of contamination in these freshwater sources … due to farm waste and fertilizer runoff. Municipal and industrial waste discharges … [as well as] junk that industry and individuals dump directly into waterways [are also causes of pollution]. (


Main Causes Of Water Pollution & Contamination In Developing Countries

  • Waste Management, Water Management Infrastructure – lack of dedicated sewage or septic systems available, as well as the proper infrastructure to treat waste water and waste in general. This waste and wastewater gets into freshwater sources (about 80% of the world’s wastewater, largely untreated, is dumped back into the environment)
  • Agriculture – happens differently than in developed countries. A lack of modern/new agricultural practices, and improper management of animal waste contribute to water pollution.

–, and


General List Of Causes Of Water Pollution & Contamination

  • Agriculture – runoff from fertilizers, pesticides, herbicides, animal waste and other agricultural chemicals and waste
  • Sewage & Wastewater Improperly Managed, Treated & Disposed Of From Households – untreated sewage discharging and being dumped into freshwater sources or the ocean
  • Industry & Factories – Industrial discharge and dumping from factories (chemical and cleaning product production, textile industry, auto production, etc.)
  • Transport – runoff of fuel and oil from vehicles, roads and transport infrastructure into surface water, below ground and marine water sources
  • Air Pollution – explained above, but mainly comes from transport and electricity generation sectors from burning of fossil fuels
  • Mining – pollutes water via discharged mine effluent and seepage from tailings and waste rock, and other waste
  • Withdrawing Too Much Water, & Drought – depletion of groundwater and droughts can cause salinity issues in water sources 
  • Open Bathing In Water – People bathing in open rivers and freshwater sources can contaminate them
  • Open Defecation – can contaminate water sources
  • Natural Disasters – such as flooding, hurricanes etc. can cause viruses, parasites and other diseases to wash into freshwater sources
  • Nuclear Power Plant/Factory – the radioactive waste can cause contamination if not disposed of properly
  • Oil Spills – from below ground storage tanks and in the ocean via tankers
  • Municipal & Industrial/Commercial Hard Rubbish Waste Management – A lack of landfills or mismanaged hard rubbish contributes to water pollution. Also, improper waste being mixed in with municipal waste, such as batteries, asbestos, lead, and other potentially hazardous waste, also leads to pollution
  • Leaky Septic Systems and Leaky/Poorly Maintained/Poor Quality Water & Waste Infrastructure – lack of sanitation and water treatment, and domestic sewage management
  • Water Pipes – Old water pipes can contain lead and arsenic and other harmful chemicals. It’s worth noting that potentially harmful contaminants—from arsenic to copper to lead—have been found in the tap water of every single state in the United States (
  • Cross Pollution Between Water Sources – e.g. a polluted river infiltrating an underground aquifer
  • Rainwater Harvesting – being collected on roofs or in tanks that have harmful chemicals e.g. oil-based lead paint 
  • Water Politics Or Poor Political Management Of Water Quality – leads to conflicts of interest or poor management of water that leads to pollution or contamination


Major Water Polluting Countries In The World

Read about the 7 biggest culprit countries of water pollution in the world here:



Water Is Polluted & Contaminated With…

  • Bacteria, parasites and viruses
  • Hazardous chemicals and substances
  • Salinity
  • Heavy metals
  • Carcinogens
  • Radioactive waste
  • Particles and solid sedimentary waste
  • Gas
  • Nitrogen and phosphates
  • + other harmful liquids, solids, gases and substances/materials/organisms


Major water pollutants include microbes, nutrients, heavy metals, organic chemicals, oil and sediments; heat, which raises the temperature of the receiving water, can also be a pollutant. Pollutants are typically the cause of major water quality degradation around the world.

An emerging water quality concern is the impact of personal care products and pharmaceuticals, such as birth control pills, painkillers and antibiotics, on aquatic ecosystems.










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