For all test like physical, chemical or the biological tests, so we need to take the samples from the sewage for the analysis.

The following precautions must be taken while taking the sample to get the accurate results:-

1. The samples must be taken at regular intervals during the day.
2. While taking the sample the scum, suspended material, sediments and all other visible impurities, must be avoided.
3. No air-bubbles should be allowed to develop in the sample bottle,(The bottle must be completely filled sewage).
4. The sample bottle must be closed immediately by a stopper.
5. The minimum quantity of the sewage must be atleast 120cc.
6. No outside contamination should be allowed.
7. Before collecting the samples, the stopper and the bottle must be properly sterilized.
8. After collecting the analysis of the sewage must be carried within two or three hours.
9. In the process of treatment the sample must be taken and analyzed at different stages.
10. The data and time of the sample must be noted on the bottle.
11. Accuracy in the sampling, naturally will get correct results.