Pretty broad question. Are you looking for a specific group of DBPs? Regardless, suggest contacting a commercial laboratory certified to do the analyses in drinking water, such as Eurofins Eaton Analytical LLC:
As Rick suggested it would be best to contact your local Analytical laboratory and ask how much they charge to run EPA method 524.2 which is a GC/MS method that reports over 80 VOCs including thecommon THMs and EPA method 552.3 a GC/MS method for the Haloacetic Acids.
Here in California the cost for running method 524.2 is ~ $130.00
Thank you for your answer, another question arises, the operator of a Water Treatment Plant will have to pay daily (140$ + $ 45) to ensure compliance with standards?
Compliance monitoring is usually not a daily requirement for most plants. The typical frequency is likely to be quarterly, semi-annually or yearly. Of course your country or State monitoring requirements may vary.
if there is a kits to measure your disifection by products it will easy and faster but may be it will more expensive but will be fixed cost becaue it will be the same cost for whole world but for the instruments such GC/MS or HPLC with usinf differnet methods and different column I think you will pay more and different from country to another