How to test water quality? Chemical tests for limited budgets


This page in:

This page in: Français | Español | 中文
Editor’s note: this is the second piece of the blog series on low-tech water quality monitoring options.

Thanks to modern chemistry, we can detect thousands of chemicals in water, even at extremely low concentrations.  The ever-growing list of tests that are available can feel overwhelming, and the vast majority of methods require state-of-the art lab facilities. Fortunately, we don’t need to test for everything! A much smaller and more practical set of tests can provide a good sense of chemical water quality for monitoring purposes.  The good news is that there are low-tech versions of these tests for situations when budgets are limited.

Test formats

Typical low-tech, portable, field test methods for chemical water quality monitoring fall into three categories:
  • Test strips – These are small, single-use strips that change color to indicate the concentration of a specific chemical. Depending on the particular test, the user “activates” the paper or plastic strip by dipping it into the water sample and swishing it around, or by holding the strip in a stream of water. After waiting for a short time, the user compares the test strip color with a color chart to read the concentration of the chemical. These kits are extremely simple, but they are less accurate than other methods, especially if users don’t follow the instructions.
  • Color disk kits – Color disk test kits are available for a wide range of chemical tests.  In a typical set-up, the user adds a powder packet or a few drops of a liquid reagent to a water sample in a reusable plastic tube.  The user then places the sample tube in a small plastic viewing box.  This viewing box contains a plastic disk with a color gradient printed on it.  The user rotates the color disk to find the part that best matches the color of the sample, and then reads the concentration of the chemical from the disk.  Color disk kits typically have multiple steps and often include prescribed wait times, so they’re a little more complicated and costly, but generally more accurate.
  • Hand-held digital instruments – Lightweight and portable digital meters, colorimeters, and photometers are available for water testing.  They provide the most accurate results of these three testing methods, but they are also more expensive and delicate than the previous options.  These instruments require batteries and calibration.  While digital instruments are helpful to field technicians and are an essential part of any continuous or remote monitoring network, they are unlikely to be suitable for “citizen science” or crowdsourced water quality testing.

Chemical water quality parameters

Having identified various test formats, the next question is: What do we test for?  UNICEF recommends prioritizing fluoride, arsenic, and nitrate for chemical monitoring.  In areas where the earth is naturally rich in minerals that contain fluorine and arsenic, levels in well water can be high enough that chronic exposure is dangerous to human health.[1]  

How can we test for these elements?
  • Fluoride: At least one color disk test kit is available for fluoride. However, portable digital colorimeters are often preferred because of concerns over accuracy.  Ackvo Caddisfly, a testing system, recently described a colorimetric fluoride test that can be read by a smartphone app.
  • Arsenic: Portable field testing options for arsenic are limited; this contaminant is best measured in a laboratory.  Commercially available test kits do exist, but they are relatively complex and require several steps.  Although the arsenic concentrations “measured” with these test kits may be inaccurate, the kits do detect arsenic in nearly all samples greater than 100 micrograms per liter (ug/L), as well as in most samples in the 50-99 ug/L range. UNICEF has therefore recommended reporting arsenic monitoring results from these portable tests as “present” or “absent” using a reference concentration of 50 ug/L—the drinking water standard in many countries that are affected by natural arsenic contamination. 
  • Nitrate:  Both test strips and color disk test kits are available for nitrate testing. Nitrate can also be measured  with a digital meter. High levels of nutrients are associated with agricultural pollution from fertilizers (nitrogen and phosphorous) and animal waste (nitrogen).  Latrines, sewage, landfills, and industrial pollution can also contribute nitrogen.  Monitoring for nitrate is a simple way to assess the impacts of agricultural and human waste on water quality. 
Resources permitting, UNICEF suggests adding three more chemical parameters to monitoring programs: the naturally-occurring metals iron and manganese, and the overall total dissolved solids (TDS).  All three can cause taste and odor problems that might motivate consumers to seek out more appealing – and potentially unsafe – water sources.
  • Iron and Manganese: Both test strips and color disk tests are available for these two metals, which may also be measured using portable, digital instruments.  Field testing with digital equipment is considered reliable for iron and manganese.
  • TDS: TDS includes a mixture of inorganic salts, mostly sodium, chloride, potassium, calcium, and magnesium.  Rather than testing the particular components, TDS is monitored by measuring the conductivity of the water with a digital meter. There is no test strip or color disk kit that can be used here, although at least one conductivity meter interfaces with a smartphone.
In chlorinated distribution systems, it is important to monitor two more chemical parameters: pH and chlorine residual.
  • pH: pH test strips and color disk tests are widely available.  More expensive, higher-tech options include electrode-based pH meters. pH is a measure of hydrogen ion activity, which means that it tells us how acidic or basic the water is.  pH is not a pollutant, but it is a chemical master variable. It affects the behavior of other chemical constituents, including the effectiveness of residual chlorine against microbial contamination.  Sudden changes in pH can also reveal treatment plant failures or pollution events in natural water bodies (for example, illegal industrial discharge).
  • Chlorine: There are many easy ways to test residual chlorine, including test strips, color disks, and even kits designed for testing swimming pools. Portable digital meters also exist that can provide reliable, quantitative measurements.
Depending on local conditions and on the focus of a water quality monitoring project, more chemical tests can be added.  One might test for alkalinity or hardness, (including calcium, magnesium, etc.; field kits are available), chloride (an indicator of road salt or seawater intrusion; test kits exist), dissolved oxygen,[2] organic carbon levels (BOD, COD, TOC), agrochemicals (specific pesticides or fertilizers), or mining/industrial contaminants (e.g., polychlorinated biphenyls, cyanide). Finally, heavy metals like lead, mercury, copper, chromium, etc. are often of local interest. 

However, the vast majority of these additional tests are best performed in a laboratory given current technologies.  That said, low-tech testing – often involving a smartphone – is an area of active research for parameters like mercury and pesticides (also here).

Stay tuned for our next post, which will dive into microbial water quality testing!
[1] If previous testing has established that arsenic and fluoride are not a concern in a particular water system, these two parameters may be omitted in favor of more locally relevant ones.  Arsenic and fluoride contamination can also be caused by human activity like mining or industrial waste discharge.
[2] Low-tech dissolved oxygen tests require multiple steps with reagent additions followed by a drop-by-drop titration; some training may be necessary and results may be more variable than those of other test kits. Digital meters also exist.


Jessica Anne Lawson

Consultant with the World Bank Water Global Practice, South Asia Region

Pratibha Mistry

Senior Water and Sanitation Specialist

Ana Maria Nunez Torres
July 13, 2017

Could you please provide recommendations for cadmium, boron and barium? We have found these substances in high concentration levels with arsenic.
Thank you.

July 11, 2018

Best bet for these metals is a lab test. Check out and look at the Essential Testing Line. Tap Score ships you all the materials and shipping labels that you need.

July 17, 2017

Pl arrange for more and more information on quality

July 22, 2017

please where in Ghana can we get some?

August 10, 2017

Hi cоllеagueѕ, fastidious post and good argᥙments commented at this place,
I am really enjoying by these.

Esle Steyn
October 14, 2017

I teach highs school students, does any of you have ideas to make tests for water quality real and easy for them. we are going to use the water from two local dams and a borehole. tap water, distilled water as the control and bottled water. Thanks

January 14, 2018

Hello everyone,
I would like to buy some test strips and color disk kits for science fair. I live in Vietnam and I have no idea about where I can find some. Do you know what type of shop sells these tests kits?
Thank you!

January 26, 2018

Thanks for this.

February 05, 2018

We need to test for 1080 Poison in water.
Can You suggest what we would need?
Thank You.

Missa Amane
May 07, 2018

Well that's a wonderful and informative post. By following these methods we can test water easily. Thanks for sharing it. Could you tell an easy way to measure water flow ? I am looking for Liquid Level sensors to know the exact amount of water before I test it.

May 12, 2018

Hello from where I can buy the water testing strips in India

July 23, 2018

Hello, we have a landfill site that was in use in the 1970s/80s not only was domestic waste disposed of here but also medical wastes from two local hospitals and industrial waste from many factories of the area, in particular from a firm that manufactured sythentic rubber, compounds such as hydrogen cyanide powder, other items dumped here were car batteries/paints/solvents/engine oil etc. The landfill site is located in bog land and flood plain 300 metres from the main water source. please tell me what toxic chemicals do we need to test for. thank-you

anil kumar
July 27, 2018

Are you looking for water treatment chemicals? then visit Universal Water Chemicals

September 27, 2018

I'm looking for a table for water quality limits and acceptably to use in agriculture process for planting and animals creation, do you have a tip for that?

October 09, 2018

Good Information... Thanks for sharing
erp hyderabad
erp companies in hyderabad

December 28, 2018

Great post as usual! Volumetric Standard Solutions

David Svarrer
January 02, 2019

I would be very happy if you could guide me as to which electronic, simple instruments one can get, and where one can get them, for measuring water quality?
Happy New Year 2019 !!
David Svarrer

January 09, 2019

colorimetric water analyzeris a method of determining the concentration of a chemical element or ... is widely used in medical laboratories and for industrial purposes

January 17, 2019

Great artical on testing water quality. Will definitely try this procedure to test the water.
I would like to share a thing which is very useful
ExcelR is the fastest growing company providing Data science training and placement. We provide you the best faculty for training and after completing of Data science training ExcelR will provide you certificate from Malaysian University. If you are searching for data science training and placement your searching ends with ExcelR.…

water filtration systems Kannapolis
January 18, 2019

As we know water is a life and human body also made with 75 percent water. Water is very necessary of living. So we should not waste water it is in limitation for us. And second thing it is related to our health also.If we drink pure and safe water so we will be healthy and its possible when we use right way to water Filtering. Thanks for sharing.
water filtration systems Kannapolis

February 15, 2019

An excellently written article, if only all blogger offered the same level of content as you, the internet would be a much better place. Please keep it up!. Great tips, I would like to join your blog anyway. Waiting for some more review. Thank you

Prince k.Teahjay
October 01, 2019

Really learned a lot from this research work.

lilay tsegay
September 16, 2021

good,but i have one question :in our town we have not pure water ,just after trying to to identified saltless water it results to no tastefull water,therefore how can we identify the pure water(good water) from the earth simply.

Tukei Augustine
September 16, 2021

Thanks. Its a great work

Fayez Tembon
September 16, 2021

I find your content very useful as i look forward to doing some river water quality testing as part of my academic resaerch project.


Spring Hibernate Training in Chennai
September 16, 2021

Valuable one,waiting for next update...thanks for sharing...

September 16, 2021

I am really happy to say it’s an interesting post to read . I learn new information from your article , you are doing a great job . Keep it up

seo services in chennai
September 16, 2021

This is very good post I have read and I must appreciate you to have written this for us.Its really informative.

Saurav Ojha
September 15, 2021

such a nice article thanks

Sheeza Riaz
October 20, 2021

Nice content.Keep it up.

Bella lauriix
December 09, 2021

The high-quality bags and containers are a durable choice to have for daily use. These bags come in various sizes and shapes to carry food items, medicines or perfumes, etc. The advanced bags are based on activated carbon technology which makes a product 100% odor-free and durable

steve johnson
January 24, 2022

thanks for sharing