Frequently Asked Questions (FAQ): Equipments used to measure water quality and quantity

Water quality testing equipments
Water quality testing equipments

This FAQ is a compilation of basic information about a few different equipment that are helpful in measuring water quality and quantity. It gives a brief description of the instruments and explains their usage and principles. In some cases, it also gives details on how to make them at home using simple materials.

The instruments discussed include

Water testing kit

Water is often tested for various parameters like pH, turbidity, colour, conductivity etc in laboratories using the titration method. However, when one needs to test the water in the field, water testing kit come handy. These kits use the same titration principles but are light, can stand up to rough 'travel' and still give fairly accurate results. Tests for bacteriological contamination using such kits only indicate the presence or absence of contamination and not its extent. View a list of kits and manufacturers' details for more information.

 pH meter

A pH meter is an electronic device used to measure the pH (acidity or alkalinity) of a liquid (though special probes are sometimes used to measure the pH of semi-solid substances). The first commercial pH meters were built around 1936 by Radiometer in Denmark and by Arnold Orville Beckman in the United States. A typical pH meter consists of a special measuring probe (a glass electrode) connected to an electronic meter that measures and displays the pH reading. pH meters range from simple and inexpensive pen-like devices to complex and expensive laboratory instruments with computer interfaces and several inputs for indicator and temperature measurements to be entered to adjust for the slight variation in pH caused by temperature.


Chloroscope is an instrument used to check the residual chlorine in drinking water. In this test, a chlorinated water sample is taken in a glass tube after the required contact period. To this, a stipulated quantity of chemical reagent is added. The color formed is observed after 5 minutes. The formation of yellow color normally indicates the presence of chlorine (either combined or free) in the water. The more yellow the color, the greater is the chlorine residual. The amount of residual chlorine can be ascertained by comparing the colour developed in the glass tube with the standard colors already kept in the laboratory. This test, is therefore, very simple and does not require much technique or time.

Rain gauge

A rain gauge is an instrument used to measure precipitation or rainfall. It is a simple clear glass measuring jar. Most rain gauges generally measure the precipitation in millimeters. The level of rainfall is sometimes reported as inches or centimeters. Rain gauge amounts are read either manually or by automatic weather station (AWS). The frequency of readings will depend on the requirements of the collection agency. A simple and economical rain gauge can be made at home to understand how much rain falls on the rooftop, which will help calculate the potential of roof top rainwater harvesting.


Construct a rain gauge at home

Soil moisture meter

Soil moisture meter measures water content in the soil. Measuring soil moisture is important in agriculture to help farmers manage their irrigation systems more efficiently. This helps the farmer use lesser water to grow a crop and also manage the quality of the crop in a better manner during the plant growth stages.

Golf courses are now using these meters to increase the efficiencies of their irrigation systems to prevent over watering and leaching of fertilizers and other chemicals offsite. This is also useful in watering urban landscape spaces like large parks, apartment lawns etc.

There are several types of soil moisture meters starting from simple hand held devices which are economical but not very long lasting to more sophisticated electrical resistance blocks and tensiometers. The choice of the meter depends on the necessity as well as cost.


India Water Portal





IWP requests users to view the same as an introductory guide. There are several other types of equipment that are useful for the same purposes. We request our readers to add to this list as responses in this thread.