- Water quality in supply sources, distribution network and treatment plants, is continually checked through carrying out of chemical, physical, microbial and chlorine measurement tests.
- Number of laboratories:
v 10 microbial laboratory units (headquarters, the grand water treatment plants, Rasht, Anzali, Talesh, Astara, Roudsar, Roudbar, Lahijan and Langroud)
v 4 chemical laboratory units (headquarters, the grand water treatment plant, Rasht, Astara)
v 2 biological laboratory units (headquarters, the grand water treatment plant)
- Amount of consumed water disinfection and treatment substances and the related expense per month:
v 13.5 tons of chlorine gas and 12.5 tons of chlorine powder for the sum of Rls. 100,000,000 (one hundred million Rials)
v 0.5 tons of lime, 92 tones of alum and 0.65 tons of polyelectrolyte for the sum of Rls. 150,000,000 (one hundred and fifty million Rials)
v The substances required in chemical experiments for the sum of Rls. 20,000,000 (twenty million Rials)
- Frequency of sampling:
v Chemical sampling: is performed seasonally at the water sources and within the distribution network, daily-monthly at the treatment plants and monthly-seasonally at rivers Sepidroud, Gelroudbar of Lahijan and Latmahalleh of Langroud.
v Microbial sampling: is performed at monthly period and on the basis of the number of inhabitant under coverage.
v Biological sampling: is performed one time every 6 months at the water sources and in case of need within the network and every week at the grand treatment plant.
v Chlorine measurement: is performed daily and on the basis of the water-supplied population.