The world’s water resources are under increasing threat from the impacts of climate change, population growth, and pollution. As the global population grows, a persistent challenge is how to access enough water to meet humanity’s needs while also preserving the integrity of aquatic ecosystems. The Pacific Institute works on water resource issues around the globe, collaborating with stakeholders to ensure communities and nature have the water they need to thrive now and in the future.

Internationally, the Institute promotes source water protection and “green infrastructure” solutions in order to increase the climate resiliency of water systems and improve ecosystem function. The Institute collects, catalogues, and shares good practice examples of nature-based solutions; catalyzes investment in green infrastructure projects; and connects stakeholders with a common interest in advancing nature-based solutions.

In California, the Institute has played an active role at the Salton Sea for more than two decades, emphasizing the importance of the sea and the negative consequences of failing to act on its behalf. The Institute has produced leading reports on the sea, developed restoration concepts, participated on the state’s Salton Sea Advisory Committee, and continues to work actively with state agencies and local stakeholders to get real habitat constructed on the ground to benefit at-risk species and to diminish the amount of dust blowing off of the sea’s exposed lakebed.

The Institute has engaged in Colorado River research and decision-making for more than twenty years, from early reports on climate change impacts on the basin, to a 1996 report on sustainable use of the river, to policy proposals for surplus and shortage criteria and the ongoing Basin Study. We have developed pragmatic, feasible solutions to the problems that challenge the river, for the people, fish, and wildlife that depend upon it. Our Colorado River work has also included place-specific research and restoration proposals for the Salton Sea, the Laguna Reach, and the limitrophe reach of the River.

What Is Water Pollution?

Water pollution occurs when harmful substances—often chemicals or microorganisms—contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment.

What Are the Causes of Water Pollution?

Water is uniquely vulnerable to pollution. Known as a “universal solvent,” water is able to dissolve more substances than any other liquid on earth. It’s the reason we have Kool-Aid and brilliant blue waterfalls. It’s also why water is so easily polluted. Toxic substances from farms, towns, and factories readily dissolve into and mix with it, causing water pollution.

Categories of Water Pollution

Groundwater

When rain falls and seeps deep into the earth, filling the cracks, crevices, and porous spaces of an aquifer (basically an underground storehouse of water), it becomes groundwater—one of our least visible but most important natural resources. Nearly 40 percent of Americans rely on groundwater, pumped to the earth’s surface, for drinking water. For some folks 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. Ridding groundwater of contaminants can be difficult to impossible, as well as costly. Once polluted, an aquifer may be unusable for decades, or even thousands of years. Groundwater can also spread contamination far from the original polluting source as it seeps into streams, lakes, and oceans.

Surface water

Covering about 70 percent of the earth, surface water is what fills our oceans, lakes, rivers, and all those other blue bits on the world map. Surface water from freshwater sources (that is, from sources other than the ocean) accounts for more than 60 percent of the water delivered to American homes. But a significant pool of that water is in peril. According to the most recent surveys on national water quality from the U.S. Environmental Protection Agency, nearly half of our rivers and streams and more than one-third of our 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. While plants and animals need these nutrients to grow, they have become a major pollutant due to farm waste and fertilizer runoff. Municipal and industrial waste discharges contribute their fair share of toxins as well. There’s also all the random junk that industry and individuals dump directly into waterways.

Ocean water

Eighty percent of ocean pollution (also called marine pollution) originates on land—whether along the coast or far inland. Contaminants such as chemicals, nutrients, and heavy metals are carried from farms, factories, and cities by streams and rivers into our bays and estuaries; from there they travel out to sea. Meanwhile, marine debris—particularly plastic—is blown in by the wind or washed in via storm drains and sewers. Our seas are also sometimes spoiled by oil spills and leaks—big and small—and are consistently soaking up carbon pollution from the air. The ocean absorbs as much as a quarter of man-made carbon emissions.

Point source

When contamination originates from a single source, it’s called point source pollution. Examples include wastewater (also called effluent) discharged legally or illegally by a manufacturer, oil refinery, or wastewater treatment facility, as well as contamination from leaking septic systems, chemical and oil spills, and illegal dumping. The EPA regulates point source pollution by establishing limits on what can be discharged by a facility directly into a body of water. While point source pollution originates from a specific place, it can affect miles of waterways and ocean.

Nonpoint source

Nonpoint source pollution is contamination derived from diffuse sources. These may include agricultural or stormwater runoff or debris blown into waterways from land. Nonpoint source pollution is the leading cause of water pollution in U.S. waters, but it’s difficult to regulate, since there’s no single, identifiable culprit.

Transboundary

It goes without saying that water pollution can’t be contained by a line on a map. Transboundary pollution is the result of contaminated water from one country spilling into the waters of another. Contamination can result from a disaster—like an oil spill—or the slow, downriver creep of industrial, agricultural, or municipal discharge.

The Most Common Types of Water Contamination

Agricultural

Not only is the agricultural sector the biggest consumer of global freshwater resources, with farming and livestock production using about 70 percent of the earth’s surface water supplies, but it’s also a serious water polluter. Around the world, agriculture is the leading cause of water degradation. In the United States, agricultural pollution is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It’s also a major contributor of contamination to estuaries and groundwater. Every time it rains, fertilizers, pesticides, and animal waste from farms and livestock operations wash nutrients and pathogens—such bacteria and viruses—into our waterways. Nutrient pollution, caused by excess nitrogen and phosphorus in water or air, is the number-one threat to water quality worldwide and can cause algal blooms, a toxic soup of blue-green algae that can be harmful to people and wildlife.

Sewage and wastewater

Used water is wastewater. It comes from our sinks, showers, and toilets (think sewage) and from commercial, industrial, and agricultural activities (think metals, solvents, and toxic sludge). The term also includes stormwater runoff, which occurs when rainfall carries road salts, oil, grease, chemicals, and debris from impermeable surfaces into our waterways

More than 80 percent of the world’s wastewater flows back into the environment without being treated or reused, according to the United Nations; in some least-developed countries, the figure tops 95 percent. In the United States, wastewater treatment facilities process about 34 billion gallons of wastewater per day. These facilities reduce the amount of pollutants such as pathogens, phosphorus, and nitrogen in sewage, as well as heavy metals and toxic chemicals in industrial waste, before discharging the treated waters back into waterways. That’s when all goes well. But according to EPA estimates, our nation’s aging and easily overwhelmed sewage treatment systems also release more than 850 billion gallons of untreated wastewater each year.

Oil pollution

Big spills may dominate headlines, but consumers account for the vast majority of oil pollution in our seas, including oil and gasoline that drips from millions of cars and trucks every day. Moreover, nearly half of the estimated 1 million tons of oil that makes its way into marine environments each year comes not from tanker spills but from land-based sources such as factories, farms, and cities. At sea, tanker spills account for about 10 percent of the oil in waters around the world, while regular operations of the shipping industry—through both legal and illegal discharges—contribute about one-third. Oil is also naturally released from under the ocean floor through fractures known as seeps.

Radioactive substances

Radioactive waste is any pollution that emits radiation beyond what is naturally released by the environment. It’s generated by uranium mining, nuclear power plants, and the production and testing of military weapons, as well as by universities and hospitals that use radioactive materials for research and medicine. Radioactive waste can persist in the environment for thousands of years, making disposal a major challenge. Consider the decommissioned Hanford nuclear weapons production site in Washington, where the cleanup of 56 million gallons of radioactive waste is expected to cost more than $100 billion and last through 2060. Accidentally released or improperly disposed of contaminants threaten groundwater, surface water, and marine resources.

Diseases which can come from polluted drinking water

Diseases in Indigenous communities caused by germs from polluted water

Bacterial diseases

• salmonellosis
• shigellosis
• acute diarrhoea (caused by E. coli)

Viral diseases

• gastroenteritis
• hepatitis A

Parasitic

• giardiasis
• hookworm infection (there is some evidence that hookworm larvae can live in drinking water)

Stomach upsets can be caused by contaminated drinking water.

In most parts of Australia and many other countries, proper water treatment methods have almost eliminated the germs that cause many of these diseases from water supplies. However, water treatment and hygiene standards in Indigenous communities, especially small communities or camps, are often inadequate and this is why many of these diseases still occur in Indigenous communities.

The germs may get into the water:

Directly by:

• a lagoon overflow effluent pipe discharging into a river or stream supplying drinking water
• the presence of dead animals in the water
• people or other animals swimming, washing or going to the toilet in a drinking water supply

Indirectly by:

• contamination from an effluent system, such as a leach drain too close to a bore or the overflow from a lagoon flowing into a water supply
• People washing themselves or going to the toilet in or near a water source

Water contamination and how it can be prevented

Anything which contaminates water is called a contaminant or pollutant. Water can be contaminated or polluted by:

• Organic materials such as:
  • animal carcasses
  • animal and human faeces and sewage
  • food waste
  • plant matter (grass, leaves, wood)
  • oil, petrol and grease.
• Inorganic materials such as:
  • scrap metal and junk
  • sand
  • chemicals

Many of these materials can carry disease-causing germs into water supplies. Chemicals in the water supply can poison people and other animals.
Water can be contaminated at:

• the source, such as the river or bore
• in storage, such as in elevated tanks
• in the pipe system which delivers water to the user

Drinking or swimming in contaminated water can be dangerous to health.

Different types of water supplies can become contaminated in a number of ways. Some of these, and their methods of prevention are described below.

Domestic rainwater tanks

Contamination

The rain which fails onto the roof of a house is usually clean, and should not normally contain germs. However, there may be a lot of dirt and rubbish on the roof, especially if it has not rained for a long time.

This dirt might include the faeces from birds and small animals. Also, the wind can carry germs in dust blown onto the roof. When it rains the dirt and rubbish will be washed into the storage tank, along with the germs. Some of these germs may cause disease.

Dirt, animals and bird faeces can get into a storage tank if it does not have a lid. All these things can carry disease-causing germs. Often animals are trapped in water tanks and drown. As dead bodies rot, germs will grow and contaminate the water.

The inside of the tank walls and floor may also become dirty after a period of time. This dirt can contaminate the water.

Prevention

If a house has a rainwater tank as its water supply, these are the things which should be done to keep the water clean:

1. Install a first flush diverter. This prevents the first flush of water, which may have contaminants from the roof, from entering the tank.
2. Keep the roof and gutters clean.
3. Keep a lid on the water tank.
4. Check for and repair any leaks.
5. Regularly look into the tank. If the water or walls or floor are dirty the tank will need to be cleaned.

Rivers and billabongs

Contamination

There are several ways in which rivers and billabongs can become contaminated with germs or chemicals:

• Rubbish may fall into or be washed into the river or billabong, for example, from a nearby dump
• Sewage may seep into the river or billabong from nearby septic tanks and leach drains
• Faeces may be deposited directly into the river by people or other animals
• Faeces deposited near the river may be washed into it by rain
• Chemicals or poisons sprayed onto land near the river or billabong may be washed into the water
• People or animals may wash themselves in the river or billabong

There is a risk that the water supply will be contaminated if the community pumps its water from a place:

• near where a contaminant enters the water such as an effluent discharge point
• where contamination is occurring, such as a swimming area

Faeces contaminate drinking water.

People washing or swimming in a water source can pollute it.

Water supply contaminated by effluent discharge.

Prevention

It is important to try and stop the river or billabong from being contaminated, particularly in the area from which the community takes its water supply. Discharging effluent into rivers and streams should always be avoided.

Sometimes it is not possible to stop the contamination of a river or billabong. This is because the contamination source is not known, or cannot be controlled, like if the contamination is occurring upstream or is because of not being able to keep cattle out of a billabong.

The following prevention methods can be adopted:

1. If the community water supply comes from a river make sure:
   • it is obtained upstream from any possible contamination sources, for example, swimming holes or effluent runoff points
   • it is taken from the deepest possible point in the body of water
2. Make sure that there is little or no building development near the water supply source. There are laws which control where people can put septic tanks/leach drains, effluent ponds, and rubbish tips in relation to water supplies.
3. Make sure people do not use the area around the water supply source for recreational purposes, such as playing sport and having picnics.
4. In the case of a billabong, it may be possible to fence the water source to prevent contamination by people and other animals.

Take drinking water upstream from effluent discharge.

Bores

Contamination

Bores can become contaminated:

• underground. (This can happen if a contaminant is able to get to the water body, for example, if a leach drain is built too close to the water source, or a faulty effluent disposal system allows disease-causing germs to soak down into the groundwater)
• While bringing it to the surface

Leach drain too close to water supply.

This could occur in the bore itself or at the place where the bore pipe comes out of the ground. This is called the bore head.

If the bore head is unprotected then animals can spread disease causing germs and parasites to the water via the equipment. For example, if the equipment leaks and allows water to pool, animals will be attracted (especially stock and birds) and their faeces may enter the water at the bore head.

Prevention

It is important that:

1. covers be placed over bore heads
2. there are fences around bore heads to keep animals away
3. the bore head area is protected from flooding as this can carry disease-causing germs into the bore. The bore head is usually protected by raising it above ground level
4. septic tanks/leach drains and effluent disposal sites are well away from the bore.

Protective cover for bore.

Laws control the distances these facilities must be away from a bore or water source.

Community water tanks

Contamination

If a large community tank does not have a proper fitting lid, then people, especially children, birds or other animals may find their way into it and contaminate the water with disease-causing germs.

Occasionally, the inside of the community water tank will get dirty and can contaminate the water.

Prevention

To make sure that the water in the community tank is always clean:

• The tank should have a proper fitting lid
• There should be a high fence, with a locked gate, around the tank
• The tank should be regularly inspected to make sure that it is not leaking and that the water is clean and free of animals, such as frogs
• If the inside of the tank is dirty it must be cleaned. The proper way to clean a tank is described in Section 6.2

Community water pipes and household plumbing

Contamination

A water supply can become contaminated between the source and the community water tank or the user. The pipes that carry the water can be below or on the surface of the ground. They can be above the ground also, such as in the case of pipes carrying water from an elevated tank to the ground. An elevated tank is one that is raised above the user’s water outlets either on a stand or on a hill.

Community elevated water tank.

If a pipe is leaking around a joint or has been broken, disease-causing germs and parasites can get into the water and contaminate it. These germs and parasites can come from:

• the surrounding soil
• the wind
• animals, including people, attracted to leak or the pools of water.

Prevention

Contamination of water in pipes can be avoided by ensuring that:

• all joints are maintained free of leaks
• pipes are placed below ground whenever possible to protect them from damage
• any above ground pipes are held secure and are protected from damage, especially from vehicles
• any leaks or broken pipes are repaired as soon as possible
• connections to tanks, pumps and bores are well maintained and kept free of leaks