For drinking water I recommend methods described by the book "Standard Methods for the Examination of Water and Wastewater". Basically, titration procedures for chloride, total hardness, calcium (you can calculate magnesium from the previous 2), and a UV spectrophotometric method for nitrate.

Cheers

I would recommend use of ion electrodes for the measurement of Nitrate. It would be comparably easy and more accurate than spectrophotometric analysis. For chlorine, DPD method is good but be careful and check each time the molarity of FAS before titration. As suggested by Mario Silva, for calcium, EDTA titration is perfect.

In general, I agree with the answers that were given above. I would like to add that spectrophotometrical methods or titrations can usually ask some time. Another option would be to use commercial test kits. I can recommend the products from Hach lange®, which are often used for for research purposes. Different testkits are available e.g. for NH4+ , NO3-, NO2- , Cl- ,etc.

I also recommend HACH Lange products (spectrophotometer), because they offer great sophistication especially in reactifs, and the latest HANG lange models guide you through operation analysis.

The most accurate methods are described in Standard Methods for the Examination of Water and Wastewater.

Silver nitrite

Spectrophotometer instrument and titration methods are used to determined of water and wastewater.

Nitrate: spectrophotometry

Calcium: Flame Photometry and Titration

Chlorine: Titration

Khaled Muftah Elsherif do you think that flame photometry and titration are easier than spectrophotometric methods ?

I agree with @Khaled Muftah Elsherif

For Ca , Flame Photometry is easier

For NO3 , Spectrophotometry is the best

I believe that specterophometry is the best way to evaluate chemical content in water.

It use the light-wave absorbation to determine the elements content

Thank you All for providing valuable suggestions.