We’ve already put together a guide about fresh water resources and supplies on Earth.
But, below is a short list of the different sources of fresh water, and a description of each.
Summary – Sources Of Freshwater
Sources of freshwater can be put into various different categories.
Some of those different categories might include:
– Potable (drinking) vs non potable water (non drinking water used for activities like irrigation for agriculture)
– Naturally formed vs man-made water sources
– Naturally renewable vs human generated water
Potable vs Non Potable Water
A city’s potable water supplies are usually tracked separately to non potable water supplies.
Drinking water usually goes through a filtering and treatment process in developed countries.
Non potable water has different water quality standards it has to meet as it isn’t being directly consumed.
It’s possible for a city to have secure potable water supplies, whilst have scarce non potable water supplies.
Natural vs Man Made Fresh Water
Natural sources of freshwater are naturally formed. Rainwater and the hydrological cycle generally recharges these sources of water.
Man made sources are constructed by humans, and can harvest/capture, or generate water.
Natural Sources Of Freshwater
A few of the main natural sources of water are:
– Surface water (lakes, ponds, rivers, etc)
– Groundwater (underground aquifers – usually take a longer time to recharge as water has to percolate through the soil down to the aquifer. Ground water can interestingly be recharged by humans as well by filtering or injecting water into them)
Man Made Sources Of Freshwater
A few of the main man made sources of freshwater are:
– Water From Atmosphere/Air (Atmospheric Water Generation)
– Dams, wells and other infrastructure or construction that harvests or captures rain water (such as rainwater harvesting)
When talking about a city’s water supply, there’s also transboundary water transfers to consider, where States/provinces, and sometimes countries can trade or buy/sell water between each other.
Renewal Of Freshwater Sources vs Generating Fresh Water
Some water sources rely on natural renewal of their supplies from the hydrological cycle and rainfall (such as surface water and ground water), whilst others can generate a certain amount of fresh water per month of annually (such as desalination).
Desalination uses saltwater, and sometimes brackish water.
A technology like water recycling uses some types of waste water.
Includes sources such as lakes, rivers, dams, and so on. Dams are a man made surface water source.
They renew when rain water falls directly into them, or when catchment areas funnel water into them.
Groundwater includes aquifers found underground
They renew naturally via rain water water percolating and infiltrating through the rocks and soil from Earth’s surface, and to a lesser extent from surrounding surface water sources.
They can also be recharged artificially through ground water replenishment schemes (e.g. injecting or filtering treated waste water directly into the aquifer)
They typically take 5 years or more to see a meaningful change in water levels i.e. their recharge rate can be slow.
Desalination (removal of total dissolved solids, and water pollutants and contaminants) involves the generation of fresh water from generally inadequate quality water (for drinking or non potable uses), such as sea water, and brackish water.
There’s various types of desalination, and there’s many desalination plants all around the world.
Water From Air/Atmosphere
Water can be extracted or drawn from the air via a number of methods.
One way that an atmospheric water generator does this for example is via refrigeration cycles that cool the air to below the dew point, the point at which condensation will form.
The end result is potable water.
Water Recycling & Re-Use
Not technically a water source, but, it is a way to supply and use water that has already been used.
Water recycling and re-use involves re-using water either with or without treatment for contamination/water pollution.
A few examples of are re-using waste water from industry, or re-using agricultural run-off water.
Read more about the pros and cons of water recycling in this guide
What Are The Main Sources Of Water?
It depends on the country.
Even different cities, towns and regions within a country can each have different main sources of water that they use for both drinking water, and non potable water.
What Is The Main Source Of Water In The US?
Nrdc.org indicates that most of the public supply tap water in the US comes from surface water sources:
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
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
Worldatlas.com indicates that different cities and States within the US get their drinking water from different types of sources such as lakes, rivers, reservoirs, aquifers, aqueducts, and so on.
What Is The Main Source Of Water In The UK?
About one third of tap water in England and Wales comes from underground sources (aquifers), in Northern Ireland and Scotland this figure is 6% and 3%, respectively. The rest comes from reservoirs, lakes, and rivers.
Namely, surface water in the UK accounts for 68% and mixed sources for 4% of the supply
What Is The Main Source Of Water In India?
India is one of the major ground water users in the world.
India [uses] 25% of all groundwater extracted globally, ahead of the US and China
Some 90% of rural India’s drinking water comes from groundwater and 75% of agriculture is groundwater-based.
In urban India, 50% of the water supply is groundwater-based
What Is The Main Source Of Water In Australia?
Some cities such as Perth rely heavily on desalination.