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Introduction to Drinking Water Quality: A Layperson’s Guide to Water Quality, Waterborne Diseases and Water Quality Monitoring
Poor water quality is a global health crisis. Not everyone who must help remedy this monumental problem is a scientist, or policy maker, or water, sanitation and hygiene expert, or public health professional. However, everyone at every level must have some understanding of the subject and science behind it.
Our booklet provides basic information to help people make intelligent decisions about safe drinking water.
Introduction to Drinking Water Quality: A Layperson’s Guide to Water Quality, Waterborne Diseases and Water Quality Monitoring
DRINKING WATER QUALITY
A Layperson’s Guide to
Water Quality, Waterborne Diseases
and Water Quality Monitoring
A Publication by
Why Water Quality
“Improved” Water vs. “Safe” Water
Global Health Crisis
How Water Becomes Contaminated
Corrective Actions to Improve Water Quality
UN Sustainable Development Goal 6 (SDG 6)
Water Quality Monitoring
Aquagenx Compartment Bag Test (CBT)
Aquagenx Procurement Programs for SDG 6
Poor water quality is a global health
crisis with many layers of complexity.
Not everyone who must help remedy
this monumental problem is a
scientist, or policy maker, or water,
sanitation and hygiene expert, or
public health professional.
However, everyone involved with this
challenge at every level must have
some understanding of the subject and
science behind it.
This booklet provides basic
information to help people make
intelligent decisions about safe
It’s also an introductory resource for
United Nations Sustainable
Development Goal 6. All stakeholders
for targets in this goal, including
people who aren’t scientists or water
professionals, need an elementary
understanding of water quality.
“More people die from unsafe
water than from all forms of
war…These deaths are an
affront to our common
humanity, and undermine the
efforts of many countries to
“The quality of drinking-water is a powerful
environmental determinant of health.
Assurance of drinking-water safety is a
foundation for the prevention and control
of waterborne diseases.”
“Water and sanitation are at the very
core of sustainable development, critical
for thriving people, planet and
Safe and sufficient water supplies are
mandatory for the health and well-being
of humans and ecosystems, and for
social and economic development.
The United Nations says safe water is a
fundamental human right.
Source: Intentional Living
Throughout much of the 20th
century, water scarcity in
developing countries – insufficient
water quantity – was the focus of
Billions of dollars were spent on
improving access to water supplies
Source: Rajnikant V/s
Water quantity is still an
enormous problem in much of
the developing world.
However, water quality is just
as important as water quantity.
All the investment in the world to improve
water access is wasteful if the water
quality in those sources is contaminated,
causing death and disease.
Water quality has rightfully become a
Source: Sri Lanka Sunday Observer
Despite the growing
concern, water is rarely
monitored for quality
in the developing world.
Source: ChildFund International
Due to the achievements of
the UN Millennium
Development Goals and the
work of NGOs, governments
and other entities, there has
been good progress toward
safe drinking water in
91% of the global population now
uses an improved drinking water
2.6 billion people have gained access
to an improved drinking water source
These promising statistics
are somewhat deceiving…
In 2015, 663 million people still lack access to
improved water sources (Joint Monitoring
The UN Joint Monitoring Program’s
definition of “improved” water
refers to the construction of a
source – if the source is protected
in some way.¹
It does not refer to the quality of
Billions of dollars have been spent
on improving water sources, but
there is recognition that an
improved water source does not
always equal safe water.
Water quality testing studies on
improved water sources reveal
those sources contain a high level
of fecal contamination.
WATER QUALITY IS A
GLOBAL HEALTH CRISIS
Source: Top News Health
World Health Organization and
UNICEF Joint Monitoring Program
663 million people - 1 in 10 - lack
access to safe water
World Health Organization
1 billion people lack access to an
2 million annual deaths
attributable to unsafe water, sanitation
Centers for Disease Control and Prevention
780 million people do not have access to an
improved water source
Estimated 800,000 children younger than
5 years of age die from diarrhea each year
About 3.5 million deaths related to
inadequate water supply, sanitation and
hygiene occur each year, predominantly
in developing countries
In 2015, the World Economic
Forum said the water crisis is
the #1 global risk based on
impact to society as a measure of
In 2016, the World Economic
Forum ranked the water crisis as
the top global risk to industry
and society over the next
Unsafe drinking water is especially tragic because
the crisis is preventable.
Source: Rochester Institute of Technology
What is lurking in water that
causes such tragedy?
Four types of organisms transmit
Source: MAD Water
The greatest waterborne risk
to health comes from the
transmission of fecal pathogens.
Fecal coliforms are a group of total
coliforms found in the intestines
and feces of humans and warm-
In any given sample of drinking
water, the concentration of
pathogens might be small, but the
number of different pathogens is
It’s impossible and too expensive to
test for all pathogens in drinking
water. Instead, we look for indirect
evidence of pathogens by testing
for indicator organisms.
Source: Sisters of Notre Dame
E. coli is a bacteria that is
the most reliable indicator
of fecal contamination and
pathogens in water.
Why is that?
E. coli is generally not found growing and
reproducing in the environment.
It has to be introduced into the environment
via the feces of humans and warm-blooded
HOW WATER BECOMES
At the Source
o Leaking septic tanks and latrines
o Contaminated surface water run-off entering
wells, springs, other sources
o Wells with defective casings, liners
o Collecting water with unwashed hands and/or
o Objects falling into the well/source
o Animals using the same source
o Open defecation
At the Household Level
o Transporting water from the source to house
in dirty containers
o Storing water in open and/or dirty containers
o Handling water with dirty hands or utensils
Natural Disasters and Emergencies
o Via disaster itself such as flood waters
o Poor sanitation and hygiene amongst
displaced populations, such as in refugee
Ensuring safe water supplies after
a disaster is one of most
important public health
requirements to prevent the
spread of waterborne diseases,
along with adequate sanitation.
Water quality testing for E. coli
following a disaster is critical.
Water sources that were once clean
can become recontaminated.
Most waters are more vulnerable to
E. coli contamination during and
shortly after precipitation events
and especially when there is
flooding. Water sources can also
become recontaminated in the
ways described on pages 34-36.
CORRECTIVE ACTIONS TO
IMPROVE WATER QUALITY
Source: Virtual Medical Centre
When contaminated water is found, it is best to take actions to identify the
reasons for the contamination by doing a sanitary assessment or
See the following examples:
Another recommended action is to
take steps to correct any water point
deficiencies, based on findings from
the sanitary inspection/assessment.
The actions depend on the types of
Some corrections or fixes are
obvious, such as: restricting animals
from accessing the water; adopting
good sanitation and hygiene
practices such as washing hands with
soap; not allowing surface water
sources for drinking water to be used
for other purposes such as human or
animal waste disposal or bathing.Source: pinterest.com
For unimproved waters that are
typically of higher risks, treating
the water is probably the best
Treating water can be done at
the water source point (where
the water is collected) or at the
point of use in the home
(household water treatment).
The United Nations Sustainable Development Goals pick up
where the Millennium Development Goals left off in 2015.
Sustainable Development Goals are the 2030 Agenda.
Sustainable Development Goal 6 (SDG 6) is a dedicated
goal for water and sanitation. SDG 6 expands on the
Millennium Development Goals focus on drinking water and
sanitation and covers the entire water cycle, including water
management, wastewater and ecosystems.
Target 6.1: “By 2030, achieve universal and equitable
access to safe and affordable drinking water for all.”
Target 6.3: “By 2030, improve water quality by
reducing pollution, eliminating dumping and minimizing
release of hazardous chemicals and materials, halving
the proportion of untreated wastewater and increasing
recycling and safe reuse globally.”
SDG 6 champions water quality.
Targets involving water quality include…
In addition, SDG Goal 11 for safe cities references water
and natural disasters…
Target 11.5 “By 2030, significantly reduce the number of
deaths and the number of people affected and
substantially decrease the economic losses relative to
gross domestic product caused by disasters, including
water-related disasters, with a focus on protecting the
poor and people in vulnerable situations.”
SDG 6 is more ambitious
than the Millennium
The new water targets are
specific, measurable and
SDG 6 recognizes there is a need to
test water at the household level
to both understand where water is
unsafe and then to validate and audit
various efforts to improve household
and community water quality.
Accurate assessment of progress
toward safe water targets includes
measuring E. coli concentrations in
drinking water with accessible,
precise tests.Source: waterencyclopedia.com
Measuring water quality with
quantifiable data is crucial to
ensure water sources and
supplies remain safe to drink
over time, and to understand
how water quality changes over
This requires ongoing water
One of the most important ways
to eliminate the global water crisis
of unsafe drinking water is to
conduct ongoing water quality
This should include routine
bacteriological testing, and
measuring water samples for the
presence of fecal pathogens,
especially E. coli.
Ongoing water quality monitoring must
be done in a health risk-based
We have to measure the presence of
fecal organisms to know the extent of
the health risk.
We have to obtain data to help make
informed decisions about drinking water
quality in order to take the most
appropriate corrective actions.
Water quality should be monitored for
safety over time, from the source or
point of production, to the point of use
and every point in between:
Point of use
Non-households (schools, healthcare
Source: Living Water International
Water quality monitoring has
been extremely difficult to do
in low resource, rural and
Part of the problem has been
various water quality testing
methods that aren’t
convenient and practical
for use in these settings.
Source: Lawrence Berkeley National Laboratory
Laboratories are often inaccessible or
unavailable in remote locations and
Lab testing is expensive. You have to
factor in sample transportation,
sample analysis and processing and
Labs can also take a long time to
generate and provide test results.
Water quality testing methods such as
membrane filtration present roadblocks
in low resource settings.
Complicated systems that are
difficult for anyone to use
Require electricity, other
resources, trained technicians
Require constant temperature
control in an incubator
Require extra, bulky equipment
that’s difficult to transport and
Require removable pieces of
equipment that must be
sterilized before re-use
Require a cold chain
Do not analyze 100 mL sample
Do not provide quantitative
on-site water quality
In order to easily monitor water quality no
matter who is doing the testing and no
matter where they are, simple, portable
tests are needed.
Water quality tests must measure the
presence of E. coli in water samples and
generate quantified test results that
provide data to make informed
decisions about water safety.
The Aquagenx Compartment Bag Test (CBT)
overcomes many of the roadblocks to
on-site water quality testing.
It does exactly what the World Health
Organization recommends for water quality
testing, namely to test for E. coli bacteria in
a 100 mL water sample.
The CBT does this in a remarkable way.
The CBT is optimized for on-site water quality testing in-the-field.
Small footprint - easy to pack and carry
Simple to use - don’t have to be a scientist
Easy color-change scoring method
Quantified test results – Most Probable Number E. coli per 100 mL
WHO recommended indicator organism and sample volume
It is the ideal water quality test
for E. coli in low resource
o Rural, remote locations
o Developing countries
o Disaster and emergency areas
1. Collect 100 mL water sample
2. Dissolve E. coli growth medium in sample for about 15 minutes
3. Pour sample into compartment bag
4. Incubate 24-48 hours depending on ambient temperature
5. Score and record test results
The CBT is an every-person’s water quality test
that takes just a few simple steps to complete.
In addition to its portability
and simplicity, the CBT has
two great features for
testing in remote,
The CBT works at variable temperatures.
That’s because the enzymatic hydrolysis of our
E. coli medium’s substrate, called X-Gluc for
short, can occur during E. coli growth at a
range of temperatures.
Other tests require precise, constant
temperature control in an electricity-dependent
The CBT enables ambient temperature
incubation at 25° Celsius and above, with
test results in 24 hours.
If you’re testing in colder climates, you just
need to maintain the sample anywhere
between 25° - 44.5° Celsius and incubate for
48 hours. It takes longer for bacteria to grow
in colder temperatures.
In colder climates, you can maintain CBT samples between 25° - 44.5°
Celsius in several ways…
With the Aquagenx portable incubator,
or by other methods and techniques such as:
• Thermal coolers and bags
• Poultry or reptile incubators
• Keeping samples in warm rooms or near any type of heat source
Color changes in the CBT are easy to see.
Blue/blue-green color indicates presence
of E. coli in a compartment.
Yellow/yellow brown color indicates
absence of E. coli in a compartment.
The concentration of E. coli is estimated
from the combination of positive and
negative compartments in the bag.
To score your test results, line up your compartment bag to the
Most Probable Number (MPN) Table in the CBT Instructions sheet.
Then, match the color sequence
of your five compartments to
one of the 32 color-coded rows
on the MPN Table.
Each row gives you the Most
Probable Number (MPN) of
E. coli in the 100 mL sample.
Our table also gives the Upper
95% Confidence Interval, which
is the worst possible
concentration of E. coli you
would find if the same sample
was tested many times.
Health Risk Category E. coli CFU per 100 mL
Intermediate Risk/Probably Safe 1-10
High Risk/Probably Unsafe >10-100
Very High Risk/Unsafe >100
The health risk categories in our MPN Table match the
World Health Organization Guidelines for Drinking Water Quality, 4th Edition.
The combined data of MPN value
and upper 95% Confidence Interval
provides excellent information in
order to make informed decisions
about the health risk of water.
This is important in the WHO
Intermediate health risk categories,
because most decisions about
water safety take place in these
The CBT’s visual, color-change
test results are also a
powerful educational tool to
help communities adopt better
behaviors for sanitation and
If you only used a Presence/Absence test for
E. coli and scored a positive test result, you
wouldn’t know if only one E. coli bacterium
was in the sample or hundreds or more.
Isn’t it better to accurately measure the health
risk of drinking water and obtain data and
better information so you know more precisely
how dangerous the sample might be?
The CBT has been tested extensively by independent parties and
compared to other testing methods such as membrane filtration and
Time and time again, results are reliable and on par with more
complicated, expensive and less portable water quality tests.
Visit this webpage to read papers, studies and articles on the CBT:
“The CBT should be adopted for
standard water quality testing practices
and disaster response within the Red
Cross/Red Crescent movement and
used by all member societies working in
a water supply capacity. Its speed,
convenience and quantitative test
results add value to water quality
investigations and validate projects and
programs. It is simple to use on-site in
remote locations, and its color-change
test results are an excellent way of
raising water quality awareness for local
Australian Red Cross
“We will absolutely continue using the
CBT in our projects to test for E. coli.
It’s very easy to use, and even the
village children in Tanzania learned to
use it! The CBT is cheap, reliable, easy
to transport and easy to understand. I
recommend the CBT to anyone who
does water quality testing in developing
countries and low resource areas
without access to electricity, incubators
Engineers Without Borders
Los Angeles Professional Chapter
Tens of thousands of CBTs are used by hundreds of customers
around the world in dozens of countries.
NGOs - small, medium and large
Humanitarian relief organizations
See more testimonials and customer stories on our website:
Would you like more information on the Aquagenx CBT Kit?
Click button above to: www.aquagenx.com/contact-us
Aquagenx is committed to helping all
countries attain SDG 6 water quality
We work with governments, NGOs
and service providers to develop
tailored, affordable, sustainable CBT
Kit procurement programs that
ensure convenience and success in
meeting SDGs, especially in rural and
low resource areas.
Contact us so we can work with you to develop a
CBT Procurement Program that meets your needs for SDG 6.
CBT Procurement Program contact form:
Many of us have heard the phrase,
“What isn’t measured isn’t managed.”
For safe water quality throughout the
world, that phrase is absolutely true.
We live in a data-driven world.
Obtaining data to ensure safe water for
everyone is a requirement, not a luxury.
Simple, convenient and effective tools
like the Aquagenx CBT are readily
available to help prevent the
devastating impact of contaminated
water on human lives.
UN Water: http://www.unwater.org/
WHO Guidelines for Drinking Water Quality:
U.S. EPA Water Quality Criteria: http://www.epa.gov/wqc