What are the main parameters to test in drinking and waste water?

An image of a person filling a glass up with water from the tap
Published: 11 January 2023

Whilst this is not an extensive list of every parameter that is measured in drinking and wastewater, it does cover the main regular tests which are carried out to ensure drinking water is safe for human consumption and that wastewater discharged into the environment is not harmful to flora and fauna. We have listed the main tested parameters in alphabetical order:


Aluminium is a metal that can be present in water naturally. In addition, Aluminium Sulphate is commonly used as a coagulant to remove suspended solids during the drinking water treatment process which in turn is why Aluminium is parameter that is frequently tested for in the drinking water process.


High concentrations of Ammonia in wastewater is undesirable as Ammonia is toxic to aquatic life. Ammonia is therefore a critical parameter to be measured prior to discharging wastewater to the environment and wastewater treatment plants are required to test and ensure that Ammonia levels within the wastewater to not exceed certain levels.


Across the globe, most drinking water is treated with Chlorine to prevent harmful pathogens forming in the water within the drinking water distribution system and the most commonly tested parameter is Free Chlorine which provides an accurate measurement of the available Chlorine within the water which is ‘active’. Drinking water contains relatively low levels of Chlorine and thus digital meters are the most used method of testing for Free Chlorine as there is no colour interpretation or margin for error which can be encountered with chemical test kits or chemical strips.


Iron is a metal which can be present at high levels in some natural and treated waters. Iron can affect the taste and even colour of water and therefore high levels of Iron are undesirable in Drinking Water. Ferric dosing is also increasingly used to remove Phosphate in Water treatment works.


As with Iron above, this is also a metal that can be found in natural water, high concentrations of Manganese can cause discolouration and deposits may also form in the water, both of which are obviously undesirable in Drinking Water.


Depleted amounts of Dissolved Oxygen in water is an indication of pollution in the watercourse, micro-organisms multiply and consume the pollution along with the oxygen, impacting on Flora and Fauna.


Rainfall can cause varying amounts of phosphates to wash from farm soils into nearby waterways. Phosphate will stimulate the growth of plankton and aquatic plants which provide food for fish. This may cause an increase in the fish population and improve the overall water quality. However too much can cause overgrowth of plankton on the surface (Eutrophication) and deplete oxygen in the watercourse.


Used as measurement to gauge general water quality, turbidity obstructs light in water, restricting growth of marine plants etc. It is also measured at the end of the water treatment process to verify readings meet regulatory standards.


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